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Oeffinger BE, Stanczak M, Lepore AC, Eisenbrey JR, Wheatley MA. Determining Ultrasound Parameters for Bursting Polymer Microbubbles for Future Use in Spinal Cord Injury. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:888-897. [PMID: 38519360 DOI: 10.1016/j.ultrasmedbio.2024.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/24/2024]
Abstract
OBJECTIVE We believe our poly(lactic acid) (PLA) microbubbles are well suited for therapeutic delivery to spinal cord injury (SCI) using ultrasound-triggered bursting. We investigated the feasibility of clinical ultrasound bursting in situ, the optimal bursting parameters in vitro and the loading and release of a model bio-active DNA. METHODS Microbubbles were tested using clinical ultrasound in a rat cadaver SCI model. Burst pressure thresholds were determined using the change in enhancement after ultrasound exposure. Resonance frequency, acoustic enhancement, sizing and morphology were evaluated by comparing two microbubble porogens, ammonium carbonate and ammonium carbamate. Oligonucleotides were loaded into the shell and released using the found optimized ultrasound bursting parameters. RESULTS In situ imaging and bursting were successful. In vitro bursting thresholds using frequencies 1, 2.25 and 5 MHz were identified between peak negative pressures 0.2 and 0.5 MPa, believed to be safe for spinal cord. The pressure threshold decreased with decreasing frequencies. PLA bursting was optimized near the resonance frequency of 2.5 to 3.0 MHz using 2.25 MHz and not at lower frequencies. PLA microbubbles, initially with a mean size of approximately 2 µm, remained in one piece, collapsed to between 0.5 and 1 µm and did not fragment. Significantly more oligonucleotide was released after ultrasound bursting of loaded microbubbles. Microbubble-sized debris was detected when using ammonium carbamate, leading to inaccurate microbubble concentration measurements. CONCLUSION PLA microbubbles made with ammonium carbonate and burst at appropriate parameters have the potential to safely improve intrathecal therapeutic delivery to SCI using targeted ultrasound.
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Affiliation(s)
- Brian E Oeffinger
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Maria Stanczak
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical Collage at Thomas Jefferson University, Philadelphia, PA, USA
| | - John R Eisenbrey
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Margaret A Wheatley
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA.
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Doelare SAN, Nederhoed JH, Evers JM, Roos ST, Kamp O, Musters RJP, Wisselink W, Jongkind V, Ebben HP, Yeung KK. Feasibility of Microbubble-Accelerated Low-Dose Thrombolysis of Peripheral Arterial Occlusions Using an Ultrasound Catheter. J Endovasc Ther 2024; 31:466-473. [PMID: 36172738 PMCID: PMC11110464 DOI: 10.1177/15266028221126938] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE Intra-arterial administration of microbubbles (MBs) through an ultrasound (US) catheter increases the local concentration of MBs into the thrombus and may further enhance outcomes of contrast-enhanced sonothrombolysis (CEST). The objective of this study was to evaluate the feasibility and lytic efficacy of intra-arterial infusion of MBs during US-enhanced thrombolysis in both in vitro and in vivo peripheral arterial occluded models. MATERIALS AND METHODS SonoVue and Luminity MBs were infused at a flow rate of 20 mL/h through either the drug delivery lumen of the US catheter (DDC, n=20) or through the tube lumen of the vascular phantom (systematic infusion, n=20) during thrombolysis with a low-dose urokinase (UK) protocol (50 000 IU/h) with(out) US application to assess MB survivability and size by pre-treatment and post-treatment measurements. A human thrombus was placed into a vascular phantom of the flow system to examine the lytic effects of CEST by post-treatment D-dimer concentrations measurements of 5 treatment conditions (saline, UK, UK+US, UK+US+SonoVue, and UK+US+Luminity). Thrombolytic efficacy of localized MBs and US delivery was then investigated in vivo in 5 porcine models by arterial blood flow, microcirculation, and postmortem determined thrombus weight and remaining length. RESULTS US exposure significantly decreased SonoVue (p=0.000) and Luminity (p=0.000) survivability by 37% and 62%, respectively. In vitro CEST treatment resulted in higher median D-dimer concentrations for the SonoVue (0.94 [0.07-7.59] mg/mL, p=0.025) and Luminity (0.83 [0.09-2.53] mg/mL, p=0.048) subgroups when compared with thrombolysis alone (0.36 [0.02-1.00] mg/mL). The lytic efficacy of CEST examined in the porcine model showed an improved median arterial blood flow of 21% (7%-79%), and a median thrombus weight and length of 1.02 (0.96-1.43) g and 2.25 (1.5-4.0) cm, respectively. One allergic reaction and 2 arrhythmias were observed due to the known allergic reaction on lipids in the porcine model. CONCLUSION SonoVue and Luminity can be combined with an US catheter and could potentially accelerate thrombolytic treatment of peripheral arterial occlusions. CLINICAL IMPACT Catheter-directed thrombolysis showed to be an effective alternative to surgery for acute peripheral arterial occlusions, but this technique is still associated with several limb and life-threatening complications. The effects of thrombolysis on clot dissolution may be further enhanced by intra-arterial administration of microbubbles through an ultrasound catheter. This study demonstrates the feasibility and lytic efficacy of intra-arterial infusion of microbubbles during US-enhanced thrombolysis in both in vitro and in vivo peripheral arterial occluded models.
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Affiliation(s)
- Sabrina A. N. Doelare
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Johanna H. Nederhoed
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Josje M. Evers
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Sebastiaan T. Roos
- Department of Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Otto Kamp
- Department of Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - René J. P. Musters
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Willem Wisselink
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Vincent Jongkind
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Surgery, Dijklander Hospital, Hoorn, The Netherlands
| | - Harm P. Ebben
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Kak K. Yeung
- Department of Surgery, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Navarro-Becerra JA, Castillo JI, Borden MA. Effect of Poly(ethylene glycol) Configuration on Microbubble Pharmacokinetics. ACS Biomater Sci Eng 2024; 10:3331-3342. [PMID: 38600786 DOI: 10.1021/acsbiomaterials.3c01764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Microbubbles (MBs) hold substantial promise for medical imaging and therapy; nonetheless, knowledge gaps persist between composition, structure, and in vivo performance, especially with respect to pharmacokinetics. Of particular interest is the role of the poly(ethylene glycol) (PEG) layer, which is thought to shield the MB against opsonization and rapid clearance but is also known to cause an antibody response upon multiple injections. The goal of this study was, therefore, to elucidate the role of the PEG layer in circulation persistence of MBs in the naïve animal (prior to an adaptive immune response). Here, we directly observe the number and size of individual MBs obtained from blood samples, unifying size and concentration into the microbubble volume dose (MVD) parameter. This approach enables direct evaluation of the pharmacokinetics of intact MBs, comprising both the lipid shell and gaseous core, rather than separately assessing the lipid or gas components. We examined the in vivo circulation persistence of 3 μm diameter phospholipid-coated MBs with three different mPEG2000 content: 2 mol % (mushroom), 5 mol % (intermediate), and 10 mol % (brush). MB size and concentration in the blood were evaluated by a hemocytometer analysis over 30 min following intravenous injections of 20 and 40 μL/kg MVD in Sprague-Dawley rats. Interestingly, pharmacokinetic analysis demonstrated that increasing PEG concentration on the MB surface resulted in faster clearance. This was evidenced by a 1.6-fold reduction in half-life and area under the curve (AUC) (p < 0.05) in the central compartment. Conversely, the AUC in the peripheral compartment increased with PEG density, suggesting enhanced MB trapping by the mononuclear phagocyte system. This was supported by an in vitro assay, which showed a significant rise in complement C3a activation with a higher PEG content. In conclusion, a minimal PEG concentration on the MB shell (mushroom configuration) was found to prolong circulation and mitigate immunogenicity.
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Affiliation(s)
- J Angel Navarro-Becerra
- Mechanical Engineering Department, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jair I Castillo
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Mark A Borden
- Mechanical Engineering Department, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
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Martinez PJ, Song JJ, Castillo J, DeSisto J, Song KH, Green AL, Borden M. Effect of Microbubble Size, Composition and Multiple Sonication Points on Sterile Inflammatory Response in Focused Ultrasound-Mediated Blood-Brain Barrier Opening. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.28.591538. [PMID: 38746278 PMCID: PMC11092473 DOI: 10.1101/2024.04.28.591538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Blood-brain barrier opening (BBBO) using focused ultrasound (FUS) and microbubbles (MBs) has emerged as a promising technique for delivering therapeutics to the brain. However, the influence of various FUS and MB parameters on BBBO and subsequent sterile inflammatory response (SIR) remains unclear. In this study, we investigated the effects of MB size and composition, as well as the number of FUS sonication points, on BBBO and SIR in an immunocompetent mouse model. Using MRI-guided MB+FUS, we targeted the striatum and assessed extravasation of an MRI contrast agent to assess BBBO and RNAseq to assess SIR. Our results revealed distinct effects of these parameters on BBBO and SIR. Specifically, at a matched microbubble volume dose (MVD), MB size did not affect the extent of BBBO, but smaller (1 μm diameter) MBs exhibited a lower classification of SIR than larger (3 or 5 μm diameter) MBs. Lipid-shelled microbubbles exhibited greater BBBO and a more pronounced SIR compared to albumin-shelled microbubbles, likely owing to the latter's poor in vivo stability. As expected, increasing the number of sonication points resulted in greater BBBO and SIR. Furthermore, correlation analysis revealed strong associations between passive cavitation detection measurements of harmonic and inertial MB echoes, BBBO and the expression of SIR gene sets. Our findings highlight the critical role of MB and FUS parameters in modulating BBBO and subsequent SIR in the brain. These insights inform the development of targeted drug delivery strategies and the mitigation of adverse inflammatory reactions in neurological disorders.
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Affiliation(s)
- Payton J. Martinez
- Biomedical Engineering Program, University of Colorado Boulder, Boulder CO 80303, United States
| | - Jane J. Song
- Biomedical Engineering Program, University of Colorado Boulder, Boulder CO 80303, United States
| | - Jair Castillo
- Biomedical Engineering Program, University of Colorado Boulder, Boulder CO 80303, United States
| | - John DeSisto
- Morgan Adams Foundation Pediatric Brain Tumor Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora CO 80045, United States
| | - Kang-Ho Song
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder CO 80303, United States
| | - Adam L. Green
- Morgan Adams Foundation Pediatric Brain Tumor Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora CO 80045, United States
| | - Mark Borden
- Biomedical Engineering Program, University of Colorado Boulder, Boulder CO 80303, United States
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder CO 80303, United States
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Cooley MB, Wegierak D, Perera R, Abenojar EC, Nittayacharn PA, Berg FM, Kim Y, Kolios MC, Exner AA. Assessing Tumor Microenvironment Characteristics and Stratifying EPR with a Nanobubble Companion Nanoparticle via Contrast-Enhanced Ultrasound Imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567934. [PMID: 38045236 PMCID: PMC10690218 DOI: 10.1101/2023.11.20.567934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The tumor microenvironment is characterized by dysfunctional endothelial cells, resulting in heightened vascular permeability. Many nanoparticle-based drug delivery systems attempt to use this enhanced permeability combined with impaired lymphatic drainage (a concept known as the 'enhanced permeability and retention effect' or EPR effect) as the primary strategy for drug delivery, but this has not proven to be as clinically effective as anticipated. The specific mechanisms behind the inconsistent clinical outcomes of nanotherapeutics have not been clearly articulated, and the field has been hampered by a lack of accessible tools to study EPR-associated phenomena in clinically relevant scenarios. While medical imaging has tremendous potential to contribute to this area, it has not been broadly explored. This work examines, for the first time, the use of multiparametric dynamic contrast-enhanced ultrasound (CEUS) with a novel nanoscale contrast agent to examine tumor microenvironment characteristics noninvasively and in real-time. We demonstrate that CEUS imaging can: (1) evaluate tumor microenvironment features and (2) be used to help predict the distribution of doxorubicin-loaded liposomes in the tumor parenchyma. CEUS using nanobubbles (NBs) was carried out in two tumor types of high (LS174T) and low (U87) vascular permeability, and time-intensity curve (TIC) parameters were evaluated in both models prior to injection of doxorubicin liposomes. Consistently, LS174T tumors showed significantly different TIC parameters, including area under the rising curve (2.7x), time to peak intensity (1.9x) and decorrelation time (DT, 1.9x) compared to U87 tumors. Importantly, the DT parameter successfully predicted tumoral nanoparticle distribution (r = 0.86 ± 0.13). Ultimately, substantial differences in NB-CEUS generated parameters between LS174T and U87 tumors suggest that this method may be useful in determining tumor vascular permeability and could be used as a biomarker for identifying tumor characteristics and predicting sensitivity to nanoparticle-based therapies. These findings could ultimately be applied to predicting treatment efficacy and to evaluating EPR in other diseases with pathologically permeable vasculature.
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Liu S, Zhao C, Zhang R, Wang Q, Wang M, Jiang Y, Yang M. Role of Ultrasonic Microbubbles in Treating Rheumatoid Arthritis: Enhancing the Efficacy of Tocilizumab via Contrast-Enhanced Ultrasound-Monitored, Ultrasound-Targeted Microbubble Destruction. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:2407-2412. [PMID: 37659958 DOI: 10.1016/j.ultrasmedbio.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/20/2023] [Accepted: 08/08/2023] [Indexed: 09/04/2023]
Abstract
OBJECTIVE Our aim was to explore the feasibility of using ultrasound-targeted microbubble destruction (UTMD) to deliver tocilizumab and enhance its efficacy in treating rheumatoid arthritis (RA). METHODS Rats with adjuvant-induced arthritis were randomly assigned to one of five treatment groups: group 1, tocilizumab + microbubbles (MBs) + UTMD; group 2, tocilizumab + MBs; group 3, tocilizumab + saline; group 4, MBs + UTMD; group 5, no treatment. We employed a commercially available ultrasound (US) machine capable of performing contrast-enhanced ultrasound (CEUS) and UTMD simultaneously using a single probe. CEUS was performed to monitor the entry and collapse of MBs. After treatment, the rats' left hindlimb paws were harvested for immunohistochemical staining of interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α). RESULTS After injection of the mixture of drugs and MBs with UTMD, significant enhancement was seen in the inflamed hindlimb paw regions, which subsided immediately on exposure to low-frequency US beams and re-appeared in the intervals between beam exposures. IL-6 expression was significantly lower in groups 1, 2 and 3 than in groups 4 and 5 (p < 0.01). Group 1 had the lowest level of IL-6 expression (p [G1 vs. G2] < 0.01, p [G1 vs. G3] < 0.01). The levels of TNF-α expression in groups 1, 2, and 3 were significantly lower than those in groups 4 and 5, but no difference was observed in these levels between groups 1-3. CONCLUSION UTMD shows promise in enhancing the treatment efficacy of anti-IL-6 drugs for RA treatment.
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Affiliation(s)
- Sirui Liu
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Chenyang Zhao
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China; Department of Ultrasonography, Peking University Shenzhen Hospital, Shenzhen, China
| | - Rui Zhang
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Qian Wang
- Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Ming Wang
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Yuxin Jiang
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Meng Yang
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
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Aliabouzar M, Quesada C, Chan ZQ, Fowlkes JB, Franceschi RT, Putnam AJ, Fabiilli ML. Acoustic droplet vaporization for on-demand modulation of microporosity in smart hydrogels. Acta Biomater 2023; 164:195-208. [PMID: 37121372 PMCID: PMC10538466 DOI: 10.1016/j.actbio.2023.04.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/10/2023] [Accepted: 04/25/2023] [Indexed: 05/02/2023]
Abstract
Microporosity in hydrogels is critical for directing tissue formation and function. We have developed a fibrin-based smart hydrogel, termed an acoustically responsive scaffold (ARS), which responds to focused ultrasound in a spatiotemporally controlled, user-defined manner. ARSs are highly flexible platforms due to the inclusion of phase-shift droplets and their tunable response to ultrasound through a mechanism termed acoustic droplet vaporization (ADV). Here, we demonstrated that ADV enabled consistent generation of micropores in ARSs, throughout the entire thickness (∼5.5 mm), utilizing perfluorooctane phase-shift droplets. Size characteristics of the generated micropores were quantified in response to critical parameters including acoustic properties, droplet size, and shear elastic modulus of fibrin using confocal microscopy. The findings showed that the length of the generated micropores correlated directly with excitation frequency, peak rarefactional pressure, pulse duration, droplet size, and indirectly with the shear elastic modulus of the fibrin matrix. The ADV-generated micropores in ARSs were further compared with cavitation-mediated micropores in fibrin gels without droplets. Additionally, the Keller-Miksis equation was used to predict an upper bound for micropore formation in ARSs at varying driving frequencies and droplet sizes. Finally, our in vivo studies showed that host cell migration following ADV-induced micropore formation was frequency-dependent, with up to 2.6 times higher cell migration at lower frequencies. Overall, these findings demonstrate a new potential application of ADV in hydrogels. STATEMENT OF SIGNIFICANCE: Interconnected micropores within a hydrogel can facilitate many cell-mediated processes. Most techniques for generating micropores are typically not biocompatible or do not enable controlled, in situ micropore formation. We used an ultrasound-based technique, termed acoustic droplet vaporization, to generate microporosity in smart hydrogels termed acoustically responsive scaffolds (ARSs). ARSs contain a fibrin matrix doped with a phase-shift droplet. We demonstrate that unique acoustic properties of phase-shift droplets can be tailored to yield spatiotemporally controlled, on-demand micropore formation. Additionally, the size characteristics of the ultrasound-generated micropores can be modulated by tuning ultrasound parameters, droplet properties, and bulk elastic properties of fibrin. Finally, we demonstrate significant, frequency-dependent host cell migration in subcutaneously implanted ARSs in mice following ultrasound-induced micropore formation in situ.
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Affiliation(s)
- Mitra Aliabouzar
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - Carole Quesada
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Ze Qi Chan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Renny T Franceschi
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Dental School, University of Michigan, Ann Arbor, MI, USA
| | - Andrew J Putnam
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
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Øygard SH, Ommen ML, Tomov BG, Diederichsen SE, Thomsen EV, Stuart MB, Larsen NB, Jensen JA. Contrast-enhanced ultrasound imaging using capacitive micromachined ultrasonic transducers. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:1887. [PMID: 37002075 DOI: 10.1121/10.0017533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 02/20/2023] [Indexed: 05/18/2023]
Abstract
Capacitive micromachined ultrasonic transducers (CMUTs) have a nonlinear relationship between the applied voltage and the emitted signal, which is detrimental to conventional contrast enhanced ultrasound (CEUS) techniques. Instead, a three-pulse amplitude modulation (AM) sequence has been proposed, which is not adversely affected by the nonlinearly emitted harmonics. In this paper, this is shown theoretically, and the performance of the sequence is verified using a 4.8 MHz linear capacitive micromachined ultrasonic transducer (CMUT) array, and a comparable lead zirconate titanate (PZT) array, across 6-60 V applied alternating current (AC) voltage. CEUS images of the contrast agent SonoVue flowing through a 3D printed hydrogel phantom showed an average enhancement in contrast-to-tissue ratio (CTR) between B-mode and CEUS images of 49.9 and 37.4 dB for the PZT array and CMUT, respectively. Furthermore, hydrophone recordings of the emitted signals showed that the nonlinear emissions from the CMUT did not significantly degrade the cancellation in the compounded AM signal, leaving an average of 2% of the emitted power between 26 and 60 V of AC. Thus, it is demonstrated that CMUTs are capable of CEUS imaging independent of the applied excitation voltage when using a three-pulse AM sequence.
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Affiliation(s)
- Sigrid Husebø Øygard
- Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Martin Lind Ommen
- Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | | | | | - Erik Vilain Thomsen
- Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Matthias Bo Stuart
- Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Niels Bent Larsen
- Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Jørgen Arendt Jensen
- Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark
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Lai TY, Averkiou MA. Contrast-Enhanced Ultrasound with Optimized Aperture Patterns and Bubble Segmentation Based on Echo Phase. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:186-202. [PMID: 36441029 PMCID: PMC9713587 DOI: 10.1016/j.ultrasmedbio.2022.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Amplitude modulation (AM) suppresses tissue signals and detects microbubble signals in contrast-enhanced ultrasound (CEUS) and is often implemented with checkerboard apertures. However, possible crosstalk between transmitting and non-transmitting array elements may compromise tissue suppression in AM. Using AM aperture patterns other than the conventional checkerboard approach (one on, one off) may reduce the degree of crosstalk and increase the contrast-to-tissue-ratio (CTR) compared with conventional AM. Furthermore, previous studies have reported that the phase difference between the echoes in AM pulsing sequences may be used to segment tissue and microbubbles and improve tissue signal suppression and the CTR of CEUS images. However, the CTR of the image produced by alternative AM aperture patterns and the effect of segmentation approach on these alternative apertures have not been investigated. We evaluated a number of AM aperture patterns to find an optimal AM aperture pattern that provides the highest CTR. We found that the aperture that uses alternating groups of two elements, AM2, had the highest CTR for the probe evaluated. In addition, a segmentation technique based on echo phase differences (between the full and half-pulses, ΔΦAM, between the complementary half-pulses, ΔΦhalf, and the maximum of the two ΔΦmax) was also considered in the AM aperture optimization process. The segmentation approach increases the CTR by about 25 dB for all apertures. Finally, AM2 segmented with ΔΦmax had a 7-dB higher CTR in a flow phantom and a 6-dB higher contrast in a perfused pig liver than conventional AM segmented with ΔΦAM, and it is the optimal transmit aperture design.
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Affiliation(s)
- Ting-Yu Lai
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
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Myers JZ, Navarro-Becerra JA, Borden MA. Nanobubbles are Non-Echogenic for Fundamental-Mode Contrast-Enhanced Ultrasound Imaging. Bioconjug Chem 2022; 33:1106-1113. [PMID: 35476906 DOI: 10.1021/acs.bioconjchem.2c00155] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microbubbles (1-10 μm diameter) have been used as conventional ultrasound contrast agents (UCAs) for applications in contrast-enhanced ultrasound (CEUS) imaging. Nanobubbles (<1 μm diameter) have recently been proposed as potential extravascular UCAs that can extravasate from the leaky vasculature of tumors or sites of inflammation. However, the echogenicity of nanobubbles for CEUS remains controversial owing to prior studies that have shown very low ultrasound backscatter. We hypothesize that microbubble contamination in nanobubble formulations may explain the discrepancy. To test our hypothesis, we examined the size distributions of lipid-coated nanobubble and microbubble suspensions using multiple sizing techniques, examined their echogenicity in an agar phantom with fundamental-mode CEUS at 7 MHz and 330 kPa peak negative pressure, and interpreted our results with simulations of the modified Rayleigh-Plesset model. We found that nanobubble formulations contained a small contamination of microbubbles. Once the contribution from these microbubbles is removed from the acoustic backscatter, the acoustic contrast of the nanobubbles was shown to be near noise levels. This result indicates that nanobubbles have limited utility as UCAs for CEUS.
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Affiliation(s)
- John Z Myers
- Biomedical Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
| | - J Angel Navarro-Becerra
- Mechanical Engineering Department, University of Colorado, Boulder, Colorado 80309, United States
| | - Mark A Borden
- Biomedical Engineering Program, University of Colorado, Boulder, Colorado 80309, United States.,Mechanical Engineering Department, University of Colorado, Boulder, Colorado 80309, United States
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11
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Navarro-Becerra JA, Song KH, Martinez P, Borden MA. Microbubble Size and Dose Effects on Pharmacokinetics. ACS Biomater Sci Eng 2022; 8:1686-1695. [PMID: 35357814 DOI: 10.1021/acsbiomaterials.2c00043] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Optimization of contrast-enhanced imaging and focused ultrasound therapy requires a comprehensive understanding of in vivo microbubble (MB) pharmacokinetics. Prior studies have focused pharmacokinetic analysis on indirect techniques, such as ultrasound imaging of the blood pool and gas chromatography of exhaled gases. The goal of this work was to measure the MB concentration directly in blood and correlate the pharmacokinetic parameters with the MB size and dose. MB volume dose (MVD) was chosen to combine the size distribution and number into a single-dose parameter. Different MB sizes (2, 3, and 5 μm diameter) at 5-40 μL/kg MVD were intravenously injected. Blood samples were withdrawn at different times (1-10 min) and analyzed by image processing. We found that for an MVD threshold < 40 μL/kg for 2 and 3 μm and <10 μL/kg for 5 μm, MB clearance followed first-order kinetics. When matching MVD, MBs of different sizes had comparable half-lives, indicating that gas dissolution and elimination by the lungs are the primary mechanisms for elimination. Above the MVD threshold, MB clearance followed biexponential kinetics, suggesting a second elimination mechanism mediated by organ retention, possibly in the lung, liver, and spleen. In conclusion, we present the first direct MB pharmacokinetic study, demonstrate the utility of MVD as a unified dose metric, and provide insights into the mechanisms of MB clearance from circulation.
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Affiliation(s)
- J Angel Navarro-Becerra
- Mechanical Engineering Department, University of Colorado, Boulder, Colorado 80309, United States
| | - Kang-Ho Song
- Mechanical Engineering Department, University of Colorado, Boulder, Colorado 80309, United States
| | - Payton Martinez
- Biomedical Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
| | - Mark A Borden
- Mechanical Engineering Department, University of Colorado, Boulder, Colorado 80309, United States.,Biomedical Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
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12
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An Open Access Chamber Designed for the Acoustic Characterisation of Microbubbles. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12041818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Microbubbles are used as contrast agents in clinical ultrasound for Left Ventricular Opacification (LVO) and perfusion imaging. They are also the subject of promising research in therapeutics as a drug delivery mechanism or for sonoporation and co-administration. For maximum efficacy in these applications, it is important to understand the acoustic characteristics of the administered microbubbles. Despite this, there is significant variation in the experimental procedures and equipment used to measure the acoustic properties of microbubble populations. A chamber was designed to facilitate acoustic characterisation experiments and was manufactured using additive manufacturing techniques. The design has been released to allow wider uptake in the research community. The efficacy of the chamber for acoustic characterisation has been explored with an experiment to measure the scattering of SonoVue® microbubbles at the fundamental frequency and second harmonic under interrogation from emissions in the frequency range of 1.6 to 6.4 MHz. The highest overall scattering values were measured at 1.6 MHz and decreased as the frequency increased, a result which is in agreement with previously published measurements. Statistical analysis of the acoustic scattering measurements have been performed and a significant difference, at the 5% significance level, was found between the samples containing contrast agent and the control sample containing only deionised water. These findings validate the proposed design for measuring the acoustic scattering characteristics of ultrasound contrast agents.
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13
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Schoen S, Kilinc MS, Lee H, Guo Y, Degertekin FL, Woodworth GF, Arvanitis C. Towards controlled drug delivery in brain tumors with microbubble-enhanced focused ultrasound. Adv Drug Deliv Rev 2022; 180:114043. [PMID: 34801617 PMCID: PMC8724442 DOI: 10.1016/j.addr.2021.114043] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 09/27/2021] [Accepted: 11/04/2021] [Indexed: 02/06/2023]
Abstract
Brain tumors are particularly challenging malignancies, due to their location in a structurally and functionally distinct part of the human body - the central nervous system (CNS). The CNS is separated and protected by a unique system of brain and blood vessel cells which together prevent most bloodborne therapeutics from entering the brain tumor microenvironment (TME). Recently, great strides have been made through microbubble (MB) ultrasound contrast agents in conjunction with ultrasound energy to locally increase the permeability of brain vessels and modulate the brain TME. As we elaborate in this review, this physical method can effectively deliver a wide range of anticancer agents, including chemotherapeutics, antibodies, and nanoparticle drug conjugates across a range of preclinical brain tumors, including high grade glioma (glioblastoma), diffuse intrinsic pontine gliomas, and brain metastasis. Moreover, recent evidence suggests that this technology can promote the effective delivery of novel immunotherapeutic agents, including immune check-point inhibitors and chimeric antigen receptor T cells, among others. With early clinical studies demonstrating safety, and several Phase I/II trials testing the preclinical findings underway, this technology is making firm steps towards shaping the future treatments of primary and metastatic brain cancer. By elaborating on its key components, including ultrasound systems and MB technology, along with methods for closed-loop spatial and temporal control of MB activity, we highlight how this technology can be tuned to enable new, personalized treatment strategies for primary brain malignancies and brain metastases.
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Affiliation(s)
- Scott Schoen
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - M. Sait Kilinc
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hohyun Lee
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Yutong Guo
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - F. Levent Degertekin
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Graeme F. Woodworth
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA,Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, College Park, MD 20742, USA,Fischell Department of Bioengineering A. James Clarke School of Engineering, University of Maryland
| | - Costas Arvanitis
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA,Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
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14
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Zeng F, Du M, Chen Z. Nanosized Contrast Agents in Ultrasound Molecular Imaging. Front Bioeng Biotechnol 2021; 9:758084. [PMID: 34912789 PMCID: PMC8666542 DOI: 10.3389/fbioe.2021.758084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/08/2021] [Indexed: 11/13/2022] Open
Abstract
Applying nanosized ultrasound contrast agents (nUCAs) in molecular imaging has received considerable attention. nUCAs have been instrumental in ultrasound molecular imaging to enhance sensitivity, identification, and quantification. nUCAs can achieve high performance in molecular imaging, which was influenced by synthetic formulations and size. This review presents an overview of nUCAs from different synthetic formulations with a discussion on imaging and detection technology. Then we also review the progress of nUCAs in preclinical application and highlight the recent challenges of nUCAs.
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Affiliation(s)
- Fengyi Zeng
- The First Affiliated Hospital, Medical Imaging Centre, Hengyang Medical School, University of South China, Hengyang, China.,Institute of Medical Imaging, Hengyang Medical School, University of South China, Hengyang, China.,Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Meng Du
- The First Affiliated Hospital, Medical Imaging Centre, Hengyang Medical School, University of South China, Hengyang, China.,Institute of Medical Imaging, Hengyang Medical School, University of South China, Hengyang, China
| | - Zhiyi Chen
- The First Affiliated Hospital, Medical Imaging Centre, Hengyang Medical School, University of South China, Hengyang, China.,Institute of Medical Imaging, Hengyang Medical School, University of South China, Hengyang, China
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15
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Le DQ, Papadopoulou V, Dayton PA. Effect of Acoustic Parameters and Microbubble Concentration on the Likelihood of Encapsulated Microbubble Coalescence. ULTRASOUND IN MEDICINE & BIOLOGY 2021; 47:2980-2989. [PMID: 34344561 PMCID: PMC8547186 DOI: 10.1016/j.ultrasmedbio.2021.06.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/23/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Microbubble contrast agents are commonly used for therapeutic and diagnostic imaging applications. Under certain conditions, these contrast agents can coalesce on ultrasound application and form larger bubbles than the initial population. The formation of large microbubbles potentially influences therapeutic outcomes and imaging quality. We studied clinically relevant ultrasound parameters related to low-pressure therapy and contrast-enhanced ultrasound imaging to determine their effect on microbubble coalescence and subsequent changes in microbubble size distributions in vitro. Results indicate that therapeutic ultrasound at low frequencies, moderate pressures and high duty cycles are capable of forming bubbles greater than two times larger than the initial bubble distribution. Furthermore, acoustic parameters related to contrast-enhanced ultrasound imaging that are at higher frequency, low-pressure and low-duty cycle exhibit no statistically significant changes in bubble diameter, suggesting that standard contrast ultrasound imaging does not cause coalescence. Overall, this work suggests that the microbubble coalescence phenomenon can readily occur at acoustic parameters used in therapeutic ultrasound, generating bubbles much larger than those found in commercial contrast agents, although coalescence is unlikely to be significant in diagnostic contrast-enhanced ultrasound imaging. This observation warrants further expansion of parameter ranges and investigation of resulting effects.
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Affiliation(s)
- David Q Le
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Virginie Papadopoulou
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
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16
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Kuriakose M, Borden MA. Microbubbles and Nanodrops for photoacoustic tomography. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101464] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Gao Y, Wu M, Gaynes BI, Dieter RS, Xu J. Study of ultrasound thrombolysis using acoustic bubbles in a microfluidic device. LAB ON A CHIP 2021; 21:3707-3714. [PMID: 34350927 DOI: 10.1039/d1lc00276g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Thrombosis is a common medical entity associated with many forms of cardiovascular disease including myocardial infarction and stroke. Recently, ultrasound thrombolysis has emerged as a promising technique for thrombosis treatment by delivering acoustic waves onto blood clots. In this study, an ultrasound thrombolysis method is presented using an acoustic bubble-based microfluidic device. With acoustic actuation, microstreaming flow is created in the microchannel by oscillating bubbles, breaking up the blood clots in blood samples in a few milliseconds. In a low-frequency field, the effects of bubble size on microstreaming patterns and thrombolysis have been experimentally studied. Using image processing techniques, we have quantitatively investigated the relationship between the input signal and the thrombolysis performance. Additionally, the viability test proved that there are no significant detrimental effects on the blood cells after acoustic actuation. This acoustic bubble-based microfluidic device is demonstrated to be a promising platform for quantitative analysis of ultrasound thrombolysis. It opens up possibilities for future development of ultrasound thrombolysis devices for the diagnosis and treatment of heart diseases.
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Affiliation(s)
- Yuan Gao
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, IL 60607, USA.
| | - Mengren Wu
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, IL 60607, USA.
| | - Bruce I Gaynes
- Department of Ophthalmology, Loyola University Stritch School of Medicine, Maywood, IL 60153, USA
- Edward Hines Jr VA Medical Center, Hines, IL 60141, USA
| | - Robert S Dieter
- Edward Hines Jr VA Medical Center, Hines, IL 60141, USA
- Department of Medicine, Loyola University Medical Center, Maywood, IL 60153, USA
| | - Jie Xu
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, IL 60607, USA.
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18
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Le TH, Phan AHT, Le KCM, Phan TDU, Nguyen KT. Utilizing polymer-conjugate albumin-based ultrafine gas bubbles in combination with ultra-high frequency radiations in drug transportation and delivery. RSC Adv 2021; 11:34440-34448. [PMID: 35494740 PMCID: PMC9042728 DOI: 10.1039/d1ra04983f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/08/2021] [Indexed: 11/21/2022] Open
Abstract
Ultrafine bubbles stabilized by human serum albumin conjugate polyethylene glycol ameliorates the stability of complex as well as the drug payload. Polyethylene glycol presents the crucial role in releasing drug by means of acoustic sound.
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Affiliation(s)
- Thi H. Le
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam
| | - An H. T. Phan
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Khoa C. M. Le
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Thy D. U. Phan
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Khoi T. Nguyen
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
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19
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Versluis M, Stride E, Lajoinie G, Dollet B, Segers T. Ultrasound Contrast Agent Modeling: A Review. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2117-2144. [PMID: 32546411 DOI: 10.1016/j.ultrasmedbio.2020.04.014] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 05/21/2023]
Abstract
Ultrasound is extensively used in medical imaging, being safe and inexpensive and operating in real time. Its scope of applications has been widely broadened by the use of ultrasound contrast agents (UCAs) in the form of microscopic bubbles coated by a biocompatible shell. Their increased use has motivated a large amount of research to understand and characterize their physical properties as well as their interaction with the ultrasound field and their surrounding environment. Here we review the theoretical models that have been proposed to study and predict the behavior of UCAs. We begin with a brief introduction on the development of UCAs. We then present the basics of free-gas-bubble dynamics upon which UCA modeling is based. We review extensively the linear and non-linear models for shell elasticity and viscosity and present models for non-spherical and asymmetric bubble oscillations, especially in the presence of surrounding walls or tissue. Then, higher-order effects such as microstreaming, shedding and acoustic radiation forces are considered. We conclude this review with promising directions for the modeling and development of novel agents.
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Affiliation(s)
- Michel Versluis
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, Enschede, the Netherlands.
| | - Eleanor Stride
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Guillaume Lajoinie
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, Enschede, the Netherlands
| | - Benjamin Dollet
- Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire de Physique (LIPhy), Université Grenoble Alpes, Grenoble, France
| | - Tim Segers
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, Enschede, the Netherlands
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20
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Aliabouzar M, Davidson CD, Wang WY, Kripfgans OD, Franceschi RT, Putnam AJ, Fowlkes JB, Baker BM, Fabiilli ML. Spatiotemporal control of micromechanics and microstructure in acoustically-responsive scaffolds using acoustic droplet vaporization. SOFT MATTER 2020; 16:6501-6513. [PMID: 32597450 PMCID: PMC7377967 DOI: 10.1039/d0sm00753f] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Acoustically-responsive scaffolds (ARSs), which are composite fibrin hydrogels, have been used to deliver regenerative molecules. ARSs respond to ultrasound in an on-demand, spatiotemporally-controlled manner via a mechanism termed acoustic droplet vaporization (ADV). Here, we study the ADV-induced, time-dependent micromechanical and microstructural changes to the fibrin matrix in ARSs using confocal fluorescence microscopy as well as atomic force microscopy. ARSs, containing phase-shift double emulsion (PSDE, mean diameter: 6.3 μm), were exposed to focused ultrasound to generate ADV - the phase transitioning of the PSDE into gas bubbles. As a result of ADV-induced mechanical strain, localized restructuring of fibrin occurred at the bubble-fibrin interface, leading to formation of locally denser regions. ADV-generated bubbles significantly reduced fibrin pore size and quantity within the ARS. Two types of ADV-generated bubble responses were observed in ARSs: super-shelled spherical bubbles, with a growth rate of 31 μm per day in diameter, as well as fluid-filled macropores, possibly as a result of acoustically-driven microjetting. Due to the strain stiffening behavior of fibrin, ADV induced a 4-fold increase in stiffness in regions of the ARS proximal to the ADV-generated bubble versus distal regions. These results highlight that the mechanical and structural microenvironment within an ARS can be spatiotemporally modulated using ultrasound, which could be used to control cellular processes and further the understanding of ADV-triggered drug delivery for regenerative applications.
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Affiliation(s)
- Mitra Aliabouzar
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA.
| | | | - William Y Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Oliver D Kripfgans
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA. and Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA and Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Renny T Franceschi
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA and School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Andrew J Putnam
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA. and Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA and Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Brendon M Baker
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA. and Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA and Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
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21
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Xu T, Cui Z, Li D, Cao F, Xu J, Zong Y, Wang S, Bouakaz A, Wan M, Zhang S. Cavitation characteristics of flowing low and high boiling-point perfluorocarbon phase-shift nanodroplets during focused ultrasound exposures. ULTRASONICS SONOCHEMISTRY 2020; 65:105060. [PMID: 32199255 DOI: 10.1016/j.ultsonch.2020.105060] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 01/15/2020] [Accepted: 03/07/2020] [Indexed: 06/10/2023]
Abstract
This work investigated and compared the dynamic cavitation characteristics between low and high boiling-point phase-shift nanodroplets (NDs) under physiologically relevant flow conditions during focused ultrasound (FUS) exposures at different peak rarefactional pressures. A passive cavitation detection (PCD) system was used to monitor cavitation activity during FUS exposure at various acoustic pressure levels. Root mean square (RMS) amplitudes of broadband noise, spectrograms of the passive cavitation detection signals, and normalized inertial cavitation dose (ICD) values were calculated. Cavitation activity of low-boiling-point perfluoropentane (PFP) NDs and high boiling-point perfluorohexane (PFH) NDs flowing at in vitro mean velocities of 0-15 cm/s were compared in a 4-mm diameter wall-less vessel in a transparent tissue-mimicking phantom. In the static state, both types of phase-shift NDs exhibit a sharp rise in cavitation intensity during initial FUS exposure. Under flow conditions, cavitation activity of the PFH NDs reached the steady state less rapidly compared to PFP NDs under the lower acoustic pressure (1.35 MPa); at the higher acoustic pressure (1.65 MPa), the RMS amplitude increased more sharply during the initial FUS exposure period. In particular, the RMS-time curves of the PFP NDs shifted upward as the mean flow velocity increased from 0 to 15 cm/s; the RMS amplitude of the PFH ND solution increased from 0 to 10 cm/s and decreased at 15 cm/s. Moreover, amplitudes of the echo signal for the low boiling-point PFP NDs were higher compared to the high boiling-point PFH NDs in the lower frequency range, whereas the inverse occurred in the higher frequency range. Both PFP and PFH NDs showed increased cavitation activity in the higher frequency under the flow condition compared to the static state, especially PFH NDs. At 1.65 MPa, normalized ICD values for PFH increased from 0.93 ± 0.03 to 0.96 ± 0.04 and from 0 to 10 cm/s, then decreased to 0.86 ± 0.05 at 15 cm/s. This work contributes to our further understanding of cavitation characteristics of phase-shift NDs under physiologically relevant flow conditions during FUS exposure. In addition, the results provide a reference for selecting suitable phase-shift NDs to enhance the efficiency of cavitation-mediated ultrasonic applications.
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Affiliation(s)
- Tianqi Xu
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Zhiwei Cui
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Dapeng Li
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Fangyuan Cao
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Jichen Xu
- Institute of Artificial Intelligence and Robotics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China; National Engineering Laboratory for Visual Information Processing and Applications, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Supin Wang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | | | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| | - Siyuan Zhang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
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22
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Stride E, Segers T, Lajoinie G, Cherkaoui S, Bettinger T, Versluis M, Borden M. Microbubble Agents: New Directions. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:1326-1343. [PMID: 32169397 DOI: 10.1016/j.ultrasmedbio.2020.01.027] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/09/2020] [Accepted: 01/26/2020] [Indexed: 05/24/2023]
Abstract
Microbubble ultrasound contrast agents have now been in use for several decades and their safety and efficacy in a wide range of diagnostic applications have been well established. Recent progress in imaging technology is facilitating exciting developments in techniques such as molecular, 3-D and super resolution imaging and new agents are now being developed to meet their specific requirements. In parallel, there have been significant advances in the therapeutic applications of microbubbles, with recent clinical trials demonstrating drug delivery across the blood-brain barrier and into solid tumours. New agents are similarly being tailored toward these applications, including nanoscale microbubble precursors offering superior circulation times and tissue penetration. The development of novel agents does, however, present several challenges, particularly regarding the regulatory framework. This article reviews the developments in agents for diagnostic, therapeutic and "theranostic" applications; novel manufacturing techniques; and the opportunities and challenges for their commercial and clinical translation.
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Affiliation(s)
- Eleanor Stride
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.
| | - Tim Segers
- Physics of Fluids Group, Technical Medical (TechMed) Centre, MESA+ Institute for Nanotechnology, University of Twente, The Netherlands
| | - Guillaume Lajoinie
- Physics of Fluids Group, Technical Medical (TechMed) Centre, MESA+ Institute for Nanotechnology, University of Twente, The Netherlands
| | - Samir Cherkaoui
- Bracco Suisse SA - Business Unit Imaging, Global R&D, Plan-les-Ouates, Switzerland
| | - Thierry Bettinger
- Bracco Suisse SA - Business Unit Imaging, Global R&D, Plan-les-Ouates, Switzerland
| | - Michel Versluis
- Physics of Fluids Group, Technical Medical (TechMed) Centre, MESA+ Institute for Nanotechnology, University of Twente, The Netherlands
| | - Mark Borden
- Mechanical Engineering Department, University of Colorado, Boulder, CO, USA
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23
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Christensen-Jeffries K, Couture O, Dayton PA, Eldar YC, Hynynen K, Kiessling F, O'Reilly M, Pinton GF, Schmitz G, Tang MX, Tanter M, van Sloun RJG. Super-resolution Ultrasound Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:865-891. [PMID: 31973952 PMCID: PMC8388823 DOI: 10.1016/j.ultrasmedbio.2019.11.013] [Citation(s) in RCA: 172] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 11/17/2019] [Accepted: 11/20/2019] [Indexed: 05/02/2023]
Abstract
The majority of exchanges of oxygen and nutrients are performed around vessels smaller than 100 μm, allowing cells to thrive everywhere in the body. Pathologies such as cancer, diabetes and arteriosclerosis can profoundly alter the microvasculature. Unfortunately, medical imaging modalities only provide indirect observation at this scale. Inspired by optical microscopy, ultrasound localization microscopy has bypassed the classic compromise between penetration and resolution in ultrasonic imaging. By localization of individual injected microbubbles and tracking of their displacement with a subwavelength resolution, vascular and velocity maps can be produced at the scale of the micrometer. Super-resolution ultrasound has also been performed through signal fluctuations with the same type of contrast agents, or through switching on and off nano-sized phase-change contrast agents. These techniques are now being applied pre-clinically and clinically for imaging of the microvasculature of the brain, kidney, skin, tumors and lymph nodes.
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Affiliation(s)
- Kirsten Christensen-Jeffries
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, London, United Kingdom
| | - Olivier Couture
- Institute of Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS FRE 2031, PSL University, Paris, France.
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Yonina C Eldar
- Department of Mathematics and Computer Science, Weizmann Institute of Science, Rehovot, Israel
| | - Kullervo Hynynen
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Fabian Kiessling
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Meaghan O'Reilly
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Gianmarco F Pinton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Georg Schmitz
- Chair for Medical Engineering, Faculty for Electrical Engineering and Information Technology, Ruhr University Bochum, Bochum, Germany
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Mickael Tanter
- Institute of Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS FRE 2031, PSL University, Paris, France
| | - Ruud J G van Sloun
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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24
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Maresca D, Payen T, Lee-Gosselin A, Ling B, Malounda D, Demené C, Tanter M, Shapiro MG. Acoustic biomolecules enhance hemodynamic functional ultrasound imaging of neural activity. Neuroimage 2020; 209:116467. [PMID: 31846757 PMCID: PMC6955150 DOI: 10.1016/j.neuroimage.2019.116467] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/19/2019] [Accepted: 12/13/2019] [Indexed: 11/16/2022] Open
Abstract
Hemodynamic functional ultrasound imaging (fUS) of neural activity provides a unique combination of spatial coverage, spatiotemporal resolution and compatibility with freely moving animals. However, deep and transcranial monitoring of brain activity and the imaging of dynamics in slow-flowing blood vessels remains challenging. To enhance fUS capabilities, we introduce biomolecular hemodynamic enhancers based on gas vesicles (GVs), genetically encodable ultrasound contrast agents derived from buoyant photosynthetic microorganisms. We show that intravenously infused GVs enhance ultrafast Doppler ultrasound contrast and visually-evoked hemodynamic contrast in transcranial fUS of the mouse brain. This hemodynamic contrast enhancement is smoother than that provided by conventional microbubbles, allowing GVs to more reliably amplify neuroimaging signals.
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Affiliation(s)
- David Maresca
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Thomas Payen
- Physics for Medicine Paris, INSERM, CNRS, ESPCI, Paris, France
| | - Audrey Lee-Gosselin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Bill Ling
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Dina Malounda
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Charlie Demené
- Physics for Medicine Paris, INSERM, CNRS, ESPCI, Paris, France
| | - Mickaël Tanter
- Physics for Medicine Paris, INSERM, CNRS, ESPCI, Paris, France
| | - Mikhail G Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
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25
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Nio AQX, Faraci A, Christensen-Jeffries K, Raymond JL, Monaghan MJ, Fuster D, Forsberg F, Eckersley RJ, Lamata P. Optimal Control of SonoVue Microbubbles to Estimate Hydrostatic Pressure. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:557-567. [PMID: 31634833 PMCID: PMC7053253 DOI: 10.1109/tuffc.2019.2948759] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 10/16/2019] [Indexed: 05/13/2023]
Abstract
The measurement of cardiac and aortic pressures enables diagnostic insight into cardiac contractility and stiffness. However, these pressures are currently assessed invasively using pressure catheters. It may be possible to estimate these pressures less invasively by applying microbubble ultrasound contrast agents as pressure sensors. The aim of this study was to investigate the subharmonic response of the microbubble ultrasound contrast agent SonoVue (Bracco Spa, Milan, Italy) at physiological pressures using a static pressure phantom. A commercially available cell culture cassette with Luer connections was used as a static pressure chamber. SonoVue was added to the phantom, and radio frequency data were recorded on the ULtrasound Advanced Open Platform (ULA-OP). The mean subharmonic amplitude over a 40% bandwidth was extracted at 0-200-mmHg hydrostatic pressures, across 1.7-7.0-MHz transmit frequencies and 3.5%-100% maximum scanner acoustic output. The Rayleigh-Plesset equation for single-bubble oscillations and additional hysteresis experiments were used to provide insight into the mechanisms underlying the subharmonic pressure response of SonoVue. The subharmonic amplitude of SonoVue increased with hydrostatic pressure up to 50 mmHg across all transmit frequencies and decreased thereafter. A decreasing microbubble surface tension may drive the initial increase in the subharmonic amplitude of SonoVue with hydrostatic pressure, while shell buckling and microbubble destruction may contribute to the subsequent decrease above 125-mmHg pressure. In conclusion, a practical operating regime that may be applied to estimate cardiac and aortic blood pressures from the subharmonic signal of SonoVue has been identified.
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Affiliation(s)
- Amanda Q. X. Nio
- Department of Biomedical EngineeringSchool of Biomedical Engineering and Imaging SciencesKing’s College LondonLondonSE1 7EHU.K.
| | - Alessandro Faraci
- Department of Biomedical EngineeringSchool of Biomedical Engineering and Imaging SciencesKing’s College LondonLondonSE1 7EHU.K.
| | - Kirsten Christensen-Jeffries
- Department of Biomedical EngineeringSchool of Biomedical Engineering and Imaging SciencesKing’s College LondonLondonSE1 7EHU.K.
| | - Jason L. Raymond
- Department of Engineering ScienceUniversity of OxfordOxfordOX1 3PJU.K.
| | - Mark J. Monaghan
- Department of CardiologyKing’s College HospitalLondonSE5 9RSU.K.
| | - Daniel Fuster
- Institut Jean Le Rond D’Alembert, Sorbonne UniversitéCenter National de la Recherche Scientifique, UMR 7190F-75005ParisFrance
| | - Flemming Forsberg
- Department of RadiologyThomas Jefferson UniversityPhiladelphiaPA19107USA
| | - Robert J. Eckersley
- Department of Biomedical EngineeringSchool of Biomedical Engineering and Imaging SciencesKing’s College LondonLondonSE1 7EHU.K.
| | - Pablo Lamata
- Department of Biomedical EngineeringSchool of Biomedical Engineering and Imaging SciencesKing’s College LondonLondonSE1 7EHU.K.
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26
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Theoretical and Experimental Gas Volume Quantification of Micro- and Nanobubble Ultrasound Contrast Agents. Pharmaceutics 2020; 12:pharmaceutics12030208. [PMID: 32121484 PMCID: PMC7150797 DOI: 10.3390/pharmaceutics12030208] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023] Open
Abstract
The amount of gas in ultrasound contrast agents is related to their acoustic activity. Because of this relationship, gas volume has been used as a key variable in normalizing the in vitro and in vivo acoustic behavior of lipid shell-stabilized bubbles with different sizes and shell components. Despite its importance, bubble gas volume has typically only been theoretically calculated based on bubble size and concentration that is typically measured using the Coulter counter for microbubbles and nanoparticle tracking analysis (NTA) for nanoscale bubbles. However, while these methods have been validated for the analysis of liquid or solid particles, their application in bubble analysis has not been rigorously studied. We have previously shown that resonant mass measurement (RMM) may be a better-suited technique for sub-micron bubble analysis, as it can measure both buoyant and non-buoyant particle size and concentration. Here, we provide validation of RMM bubble analysis by using headspace gas chromatography/mass spectrometry (GC/MS) to experimentally measure the gas volume of the bubble samples. This measurement was then used as ground truth to test the accuracy of theoretical gas volume predictions based on RMM, NTA (for nanobubbles), and Coulter counter (for microbubbles) measurements. The results show that the headspace GC/MS gas volume measurements agreed well with the theoretical predictions for the RMM of nanobubbles but not NTA. For nanobubbles, the theoretical gas volume using RMM was 10% lower than the experimental GC/MS measurements; meanwhile, using NTA resulted in an 82% lower predicted gas volume. For microbubbles, the experimental gas volume from the GC/MS measurements was 27% lower compared to RMM and 72% less compared to the Coulter counter results. This study demonstrates that the gas volume of nanobubbles and microbubbles can be reliably measured using headspace GC/MS to validate bubble size measurement techniques. We also conclude that the accuracy of theoretical predictions is highly dependent on proper size and concentration measurements.
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27
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Lattwein KR, Shekhar H, Kouijzer JJP, van Wamel WJB, Holland CK, Kooiman K. Sonobactericide: An Emerging Treatment Strategy for Bacterial Infections. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:193-215. [PMID: 31699550 PMCID: PMC9278652 DOI: 10.1016/j.ultrasmedbio.2019.09.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 09/03/2019] [Accepted: 09/16/2019] [Indexed: 05/04/2023]
Abstract
Ultrasound has been developed as both a diagnostic tool and a potent promoter of beneficial bio-effects for the treatment of chronic bacterial infections. Bacterial infections, especially those involving biofilm on implants, indwelling catheters and heart valves, affect millions of people each year, and many deaths occur as a consequence. Exposure of microbubbles or droplets to ultrasound can directly affect bacteria and enhance the efficacy of antibiotics or other therapeutics, which we have termed sonobactericide. This review summarizes investigations that have provided evidence for ultrasound-activated microbubble or droplet treatment of bacteria and biofilm. In particular, we review the types of bacteria and therapeutics used for treatment and the in vitro and pre-clinical experimental setups employed in sonobactericide research. Mechanisms for ultrasound enhancement of sonobactericide, with a special emphasis on acoustic cavitation and radiation force, are reviewed, and the potential for clinical translation is discussed.
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Affiliation(s)
- Kirby R Lattwein
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
| | - Himanshu Shekhar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Joop J P Kouijzer
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Willem J B van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Christy K Holland
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Klazina Kooiman
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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28
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Browning RJ, Aron M, Booth A, Rademeyer P, Wing S, Brans V, Shrivastava S, Carugo D, Stride E. Spectral Imaging for Microbubble Characterization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:609-617. [PMID: 31855435 DOI: 10.1021/acs.langmuir.9b03828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Microbubbles stabilized by an outer lipid shell have been studied extensively for both diagnostic and therapeutic applications. The shell composition can significantly influence microbubble behavior, but performing quantitative measurements of shell properties is challenging. The aim of this study is to investigate the use of spectral imaging to characterize the surface properties of a range of microbubble formulations representing both commercial and research agents. A lipophilic dye, C-laurdan, whose fluorescence emission varies according to the properties of the local environment, was used to compare the degree and uniformity of the lipid order in the microbubble shell, and these measurements were compared with the acoustic response and stability of the different formulations. Spectral imaging was found to be suitable for performing rapid and hence relatively high throughput measurements of microbubble surface properties. Interestingly, despite significant differences in lipid molecule size and charge, all of the different formulations exhibited highly ordered lipid shells. Measurements of liposomes with the same composition and the debris generated by destroying lipid microbubbles with ultrasound (US) showed that these exhibited a lower and more varied lipid order than intact microbubbles. This suggests that the high lipid order of microbubbles is due primarily to compression of the shell as a result of surface tension and is only minimally affected by composition. This also explains the similarity in acoustic response observed between the formulations, because microbubble dynamics are determined by the diameter and shell viscoelastic properties that are themselves a function of the lipid order. Within each population, there was considerable variability in the lipid order and response between individual microbubbles, suggesting the need for improved manufacturing techniques. In addition, the difference in the lipid order between the shell and lipid debris may be important for therapeutic applications in which shedding of the shell material is exploited, for example, drug delivery.
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Affiliation(s)
- Richard J Browning
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
| | - Miles Aron
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
| | - Anna Booth
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
- Department of Chemistry , University of Oxford , Oxford OX1 3QR , U.K
| | - Paul Rademeyer
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
| | - Sarah Wing
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
| | - Veerle Brans
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
| | - Shamit Shrivastava
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
| | - Dario Carugo
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
- Faculty of Engineering and Physical Sciences , University of Southampton , Highfield, Southampton SO17 1BJ , U.K
| | - Eleanor Stride
- Department of Engineering Science, Institute of Biomedical Engineering , University of Oxford , Oxford OX3 7DQ , U.K
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29
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Omata D, Unga J, Suzuki R, Maruyama K. Lipid-based microbubbles and ultrasound for therapeutic application. Adv Drug Deliv Rev 2020; 154-155:236-244. [PMID: 32659255 DOI: 10.1016/j.addr.2020.07.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/11/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022]
Abstract
Microbubbles with diagnostic ultrasound have had a long history of use in the medical field. In recent years, the therapeutic application of the combination of microbubbles and ultrasound, called sonoporation, has received increased attention as microbubble oscillation or collapse close to various barriers in the body was recognized to potentially open those barriers, increasing drug transport across them. In this review, we aimed to describe the development of lipid-stabilized microbubbles equipped with functions, such as long circulation and drug loading, and the therapeutic application of sonoporation for tumor-targeted therapy, brain-targeted therapy, and immunotherapy. We also attempted to discuss the current status of the field and potential future developments.
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30
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Omata D, Maruyama T, Unga J, Hagiwara F, Munakata L, Kageyama S, Shima T, Suzuki Y, Maruyama K, Suzuki R. Effects of encapsulated gas on stability of lipid-based microbubbles and ultrasound-triggered drug delivery. J Control Release 2019; 311-312:65-73. [DOI: 10.1016/j.jconrel.2019.08.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 08/21/2019] [Accepted: 08/23/2019] [Indexed: 11/30/2022]
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31
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Newsome IG, Kierski TM, Dayton PA. Assessment of the Superharmonic Response of Microbubble Contrast Agents for Acoustic Angiography as a Function of Microbubble Parameters. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:2515-2524. [PMID: 31174922 PMCID: PMC7202402 DOI: 10.1016/j.ultrasmedbio.2019.04.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 04/25/2019] [Accepted: 04/30/2019] [Indexed: 05/07/2023]
Abstract
Acoustic angiography is a superharmonic contrast-enhanced ultrasound imaging technique that enables 3-D high-resolution microvascular visualization. This technique utilizes a dual-frequency imaging strategy, transmitting at a low frequency and receiving at a higher frequency, to detect high-frequency contrast agent signatures and separate them from tissue background. Prior studies have illustrated differences in microbubble scatter dependent on microbubble size and composition; however, most previously reported data have utilized a relatively narrow frequency bandwidth centered around the excitation frequency. To date, a comprehensive study of isolated microbubble superharmonic responses with a broadband dual-frequency system has not been performed. Here, the superharmonic signal production of 14 contrast agents with various gas cores, shell compositions, and bubble diameters at mechanical indices of 0.2 to 1.2 was evaluated using a transmit 4 MHz, receive 25 MHz configuration. Results indicate that perfluorocarbon cores or lipid shells with 18- or 20-carbon acyl chains produce more superharmonic signal than sulfur hexafluoride cores or lipid shells with 16-carbon acyl chains, respectively. As microbubble diameter increases from 1 to 4 µm, superharmonic generation decreases. In a comparison of two clinical agents, Definity and Optison, and one preclinical agent, Micromarker, Optison produced the least superharmonic signal. Overall, this work suggests that microbubbles around 1 μm in diameter with perfluorocarbon cores and longer-chained lipid shells perform best for superharmonic imaging at 4 MHz. Studies have found that microbubble superharmonic response follows trends different from those described in prior studies using a narrower frequency bandwidth centered around the excitation frequency. Future work will apply these results in vivo to optimize the sensitivity of acoustic angiography.
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Affiliation(s)
- Isabel G Newsome
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Thomas M Kierski
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
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32
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Abenojar EC, Nittayacharn P, de Leon AC, Perera R, Wang Y, Bederman I, Exner AA. Effect of Bubble Concentration on the in Vitro and in Vivo Performance of Highly Stable Lipid Shell-Stabilized Micro- and Nanoscale Ultrasound Contrast Agents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10192-10202. [PMID: 30913884 DOI: 10.1021/acs.langmuir.9b00462] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ultrasound (US) is a widely used diagnostic imaging tool because it is inexpensive, safe, portable, and broadly accessible. Ultrasound contrast agents (UCAs) are employed to enhance backscatter echo and improve imaging contrast. The most frequently utilized UCAs are echogenic bubbles made with a phospholipid or protein-stabilized hydrophobic gas core. While clinically utilized, applications of UCAs are often limited by rapid signal decay (<5 min) in vivo under typical ultrasound imaging protocols. Here, we report on a formulation of lipid shell-stabilized perfluoropropane (C3F8) microbubbles and nanobubbles with a significantly prolonged in vivo stability. Microbubbles (875 ± 280 nm) of the target size were prepared by utilizing a multiple-step centrifugation cycle, while nanobubbles (299 ± 189 nm) were isolated from the activated vial using a single centrifugation step. To provide in-depth acoustic characterization of the new construct we evaluated the effect of size and concentration on their in vitro and in vivo performance. In vitro and in vivo characterization were carried out for a range of bubble concentrations normalized by total gas volume quantified via headspace gas chromatography/mass spectrometry (GC/MS). In vitro characterization revealed that nanobubbles at different concentrations are more consistently stable over time with the highest and lowest dilutions (50-fold decrease) only differing in US signal after 8 min exposure by 10.34%, while for microbubbles the difference was 86.46%. As expected, due to the difference in hydrodynamic diameter and scattering cross section difference, nanobubbles showed lower overall initial signal intensity. In vivo experiments showed that both microbubbles and nanobubbles with similar initial peak signal intensity are comparably stable over time with 66.8% and 60.6% remaining signal after 30 min, respectively. This study demonstrates that bubble concentration has significant effects on the persistence of both microbubbles and nanobubbles in vitro and in vivo, but the effects are more pronounced in larger bubbles. These effects should be taken into account when selecting the appropriate bubble parameters for future imaging applications.
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Affiliation(s)
- Eric C Abenojar
- Department of Radiology , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Pinunta Nittayacharn
- Department of Biomedical Engineering , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Al Christopher de Leon
- Department of Radiology , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Reshani Perera
- Department of Radiology , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Yu Wang
- Department of Radiology , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Ilya Bederman
- Department of Pediatrics, School of Medicine , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Agata A Exner
- Department of Radiology , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
- Department of Biomedical Engineering , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
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Lin X, Zhang X, Wang S, Liang X, Xu Y, Chen M, Gao C, Liu R, Tang J, Dai Z, Sun D. Intraoperative Identification and Guidance of Breast Cancer Microfoci Using Ultrasound and Near-Infrared Fluorescence Dual-Modality Imaging. ACS APPLIED BIO MATERIALS 2019; 2:2252-2261. [PMID: 35030664 DOI: 10.1021/acsabm.9b00206] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Xiaona Lin
- Department of Ultrasonic Imaging, Peking University Shenzhen Hospital, Shenzhen 518035, China
| | - Xiaoting Zhang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Shumin Wang
- Department of Ultrasound, Peking University Third Hospital, Beijing 100191, China
| | - Xiaolong Liang
- Department of Ultrasound, Peking University Third Hospital, Beijing 100191, China
| | - Yunxue Xu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Min Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Chuang Gao
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Renfa Liu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Jie Tang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Zhifei Dai
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Desheng Sun
- Department of Ultrasonic Imaging, Peking University Shenzhen Hospital, Shenzhen 518035, China
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34
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Cheng M, Li F, Han T, Yu ACH, Qin P. Effects of ultrasound pulse parameters on cavitation properties of flowing microbubbles under physiologically relevant conditions. ULTRASONICS SONOCHEMISTRY 2019; 52:512-521. [PMID: 30642801 DOI: 10.1016/j.ultsonch.2018.12.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 12/03/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
Abstract
Acoustic cavitation from ultrasound-driven microbubbles can induce diverse bioeffects that are useful in clinical therapy. However, lack of control over the cavitation activity of flowing microbubbles results in unwanted treatment regions in the targeted tissue, which influences the therapeutic efficacy and bio-safety. The aim of this study is to understand the relationship between the ultrasound pulse parameters and cavitation properties of flowing microbubbles, including the type (and transition between types), threshold, intensity and temporal distribution of cavitation. An in vitro physiological-flow phantom was fabricated, in which the microbubbles had a constant velocity, and were sonicated to a 1-MHz focused transducer at a wide range of peak negative pressures (PNPs) (0.10-1.28 MPa), pulse repetition frequencies (PRFs) (1-200 Hz) and pulse lengths (PLs) (10-400 μs). The signals from the flowing bubbles were passively detected by another 7.5-MHz plane transducer. From detailed time- and frequency-domain analysis, we found 1). The occurrence of stable cavitation (SC) and inertial cavitation (IC) depended on PNP and PL when the PRF was below a critical value (PRF threshold) that related to the fluid velocity and PNP full width at half maximum diameter of the transducer. 2) Below the PRF threshold, the PL had no influence on the temporal distribution of SC intensity; however, above the PRF threshold, the SC properties depended on the PL because of acoustically-driven diffusion. Specifically, at shorter PLs, the SC intensity had a uniform temporal distribution and was independent of the PRF; at longer PLs, the SC intensity correlated negatively with the PRF. 3) Below the PRF threshold, the IC properties were independent of the PRF. Increasing the PRF above the PRF threshold caused the IC intensity to decrease with a non-uniform temporal distribution. These results indicate that the fluid velocity and a pulsed acoustic field influence the number and properties of the replenished bubbles into the targeted region, resulting in the change of cavitation properties. In future therapeutic applications, the physiological fluid conditions must be taken into consideration to design reasonable pulse parameters and achieve desirable cavitation properties.
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Affiliation(s)
- Mouwen Cheng
- Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Fan Li
- Department of Medical Ultrasound, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Tao Han
- Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Alfred C H Yu
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Peng Qin
- Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
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35
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Jones RM, Hynynen K. Advances in acoustic monitoring and control of focused ultrasound-mediated increases in blood-brain barrier permeability. Br J Radiol 2019; 92:20180601. [PMID: 30507302 DOI: 10.1259/bjr.20180601] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Transcranial focused ultrasound (FUS) combined with intravenously circulating microbubbles can transiently and selectively increase blood-brain barrier permeability to enable targeted drug delivery to the central nervous system, and is a technique that has the potential to revolutionize the way neurological diseases are managed in medical practice. Clinical testing of this approach is currently underway in patients with brain tumors, early Alzheimer's disease, and amyotrophic lateral sclerosis. A major challenge that needs to be addressed in order for widespread clinical adoption of FUS-mediated blood-brain barrier permeabilization to occur is the development of systems and methods for real-time treatment monitoring and control, to ensure that safe and effective acoustic exposure levels are maintained throughout the procedures. This review gives a basic overview of the oscillation dynamics, acoustic emissions, and biological effects associated with ultrasound-stimulated microbubbles in vivo, and provides a summary of recent advances in acoustic-based strategies for detecting, controlling, and mapping microbubble activity in the brain. Further development of next-generation clinical FUS brain devices tailored towards microbubble-mediated applications is warranted and required for translation of this potentially disruptive technology into routine clinical practice.
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Affiliation(s)
- Ryan M Jones
- 1 Physical Sciences Platform, Sunnybrook Research Institute , Toronto, ON , Canada
| | - Kullervo Hynynen
- 1 Physical Sciences Platform, Sunnybrook Research Institute , Toronto, ON , Canada.,2 Department of Medical Biophysics, University of Toronto , Toronto, ON , Canada.,3 Institute of Biomaterials and Biomedical Engineering, University of Toronto , Toronto, ON , Canada
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Unga J, Omata D, Kudo N, Ueno S, Munakata L, Shima T, Suzuki R, Maruyama K. Development and evaluation of stability and ultrasound response of DSPC-DPSG-based freeze-dried microbubbles. J Liposome Res 2019; 29:368-374. [DOI: 10.1080/08982104.2018.1556294] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Johan Unga
- Faculty of Pharma-Science, Laboratory of Drug and Gene Delivery Research, Teikyo University, Tokyo, Japan
| | - Daiki Omata
- Faculty of Pharma-Science, Laboratory of Drug and Gene Delivery Research, Teikyo University, Tokyo, Japan
| | - Nobuki Kudo
- Faculty of Engineering, Graduate School of Information Science and Technology, Laboratory of Biomedical Engineering, Hokkaido University, Sapporo, Japan
| | - Soki Ueno
- Faculty of Engineering, Graduate School of Information Science and Technology, Laboratory of Biomedical Engineering, Hokkaido University, Sapporo, Japan
| | - Lisa Munakata
- Faculty of Pharma-Science, Laboratory of Drug and Gene Delivery Research, Teikyo University, Tokyo, Japan
| | - Tadamitsu Shima
- Faculty of Pharma-Science, Laboratory of Drug and Gene Delivery Research, Teikyo University, Tokyo, Japan
| | - Ryo Suzuki
- Faculty of Pharma-Science, Laboratory of Drug and Gene Delivery Research, Teikyo University, Tokyo, Japan
| | - Kazuo Maruyama
- Faculty of Pharma-Science, Laboratory of Drug and Gene Delivery Research, Teikyo University, Tokyo, Japan
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Borden MA, Song KH. Reverse engineering the ultrasound contrast agent. Adv Colloid Interface Sci 2018; 262:39-49. [PMID: 30396507 PMCID: PMC6268001 DOI: 10.1016/j.cis.2018.10.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/09/2018] [Accepted: 10/22/2018] [Indexed: 12/31/2022]
Abstract
In this review, a brief history and current state-of-the-art is given to stimulate the rational design of new microbubbles through the reverse engineering of current ultrasound contrast agents (UCAs). It is shown that an effective microbubble should be biocompatible, echogenic and stable. Physical mechanisms and engineering calculations have been provided to illustrate these properties and how they can be achieved. The reverse-engineering design paradigm is applied to study current FDA-approved and commercially available UCAs. Given the sophistication of microbubble designs reported in the literature, rapid development and adoption of ultrasound device hardware and techniques, and the growing number of revolutionary biomedical applications moving toward the clinic, the field of Microbubble Engineering is fertile for breakthroughs in next-generation UCA technology. It is up to current and future microbubble engineers and clinicians to push forward with regulatory approval and clinical adoption of advanced UCA technologies in the years to come.
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Affiliation(s)
- Mark A Borden
- Mechanical Engineering, University of Colorado, Boulder, CO 80309-0427, USA.
| | - Kang-Ho Song
- Mechanical Engineering, University of Colorado, Boulder, CO 80309-0427, USA
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38
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Improvement of Detection Sensitivity of Microbubbles as Sensors to Detect Ambient Pressure. SENSORS 2018; 18:s18124083. [PMID: 30469461 PMCID: PMC6308843 DOI: 10.3390/s18124083] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/14/2018] [Accepted: 11/19/2018] [Indexed: 01/16/2023]
Abstract
Microbubbles are considered a promising tool for noninvasive estimation of local blood pressure. It is reported that the subharmonic scattering amplitude of microbubbles decreases by 9 to 12 dB when immersed in the media under an ambient pressure variation from 0 to 180 mmHg. However, the pressure sensitivity still needs to be improved to satisfy clinical diagnostic requirements. Here, we investigated the effects of acoustic parameters on the pressure sensitivity of microbubbles through measuring the acoustic attenuation and scattering properties of commercially available SonoVue microbubbles. Our results showed that the first harmonic, subharmonic, and ultraharmonic amplitudes of microbubbles were reduced by 6.6 dB, 10.9 dB, and 9.3 dB at 0.225 mechanical index (MI), 4.6 dB, 19.8 dB, and 12.3 dB at 0.25 MI, and 18.5 dB, 17.6 dB, and 12.6 dB at 0.3 MI, respectively, when the ambient pressure increased from 0 to 180 mmHg. Our finding revealed that a moderate MI (0.25–0.4) exciting microbubbles could significantly improve their sensitivities to detect ambient pressure.
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Senior R, Becher H, Monaghan M, Agati L, Zamorano J, Vanoverschelde JL, Nihoyannopoulos P, Edvardsen T, Lancellotti P. Clinical practice of contrast echocardiography: recommendation by the European Association of Cardiovascular Imaging (EACVI) 2017. Eur Heart J Cardiovasc Imaging 2018; 18:1205-1205af. [PMID: 28950366 DOI: 10.1093/ehjci/jex182] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 06/20/2017] [Indexed: 12/16/2022] Open
Abstract
Contrast echocardiography is widely used in cardiology. It is applied to improve image quality, reader confidence and reproducibility both for assessing left ventricular (LV) structure and function at rest and for assessing global and regional function in stress echocardiography. The use of contrast in echocardiography has now extended beyond cardiac structure and function assessment to evaluation of perfusion both of the myocardium and of the intracardiac structures. Safety of contrast agents have now been addressed in large patient population and these studies clearly established its excellent safety profile. This document, based on clinical trials, randomized and multicentre studies and published clinical experience, has established clear recommendations for the use of contrast in various clinical conditions with evidence-based protocols.
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Affiliation(s)
- Roxy Senior
- Department of Cardiology, Royal Brompton Hospital, Imperial College, Sydney Street, London SW3 6NP, UK
| | | | | | | | - Jose Zamorano
- CIBERCV, University Hospital Ramón y Cajal, Madrid, Spain
| | | | | | | | - Patrizio Lancellotti
- University of Liege Hospital, GIGA Cardiovascular Science, Heart Valve Clinic, Imaging Cardiology, Liege, Belgium
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Tran DM, Harrang J, Song S, Chen J, Smith BM, Miao CH. Prolonging pulse duration in ultrasound-mediated gene delivery lowers acoustic pressure threshold for efficient gene transfer to cells and small animals. J Control Release 2018; 279:345-354. [PMID: 29702143 DOI: 10.1016/j.jconrel.2018.04.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/08/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022]
Abstract
While ultrasound-mediated gene delivery (UMGD) has been accomplished using high peak negative pressures (PNPs) of 2 MPa or above, emerging research showed that this may not be a requirement for microbubble (MB) cavitation. Thus, we investigated lower-pressure conditions close to the MB inertial cavitation threshold and focused towards further increasing gene transfer efficiency and reducing associated cell damage. We created a matrix of 21 conditions (n = 3/cond.) to test in HEK293T cells using pulse durations spanning 18 μs-36 ms and PNPs spanning 0.5-2.5 MPa. Longer pulse duration conditions yielded significant increase in transgene expression relative to sham with local maxima between 20 J and 100 J energy curves. A similar set of 17 conditions (n = 4/cond.) was tested in mice using pulse durations spanning 18 μs-22 ms and PNPs spanning 0.5-2.5 MPa. We observed local maxima located between 1 J and 10 J energy curves in treated mice. Of these, several low pressure conditions showed a decrease in ALT and AST levels while maintaining better or comparable expression to our positive control, indicating a clear benefit to allow for effective transfection with minimized tissue damage versus the high-intensity control. Our data indicates that it is possible to eliminate the requirement of high PNPs by prolonging pulse durations for effective UMGD in vitro and in vivo, circumventing the peak power density limitations imposed by piezo-materials used in US transducers. Overall, these results demonstrate the advancement of UMGD technology for achieving efficient gene transfer and potential scalability to larger animal models and human application.
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Affiliation(s)
- Dominic M Tran
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - James Harrang
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Shuxian Song
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Jeremy Chen
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Bryn M Smith
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Carol H Miao
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington, Seattle, WA 98195, USA.
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41
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Chong WK, Papadopoulou V, Dayton PA. Imaging with ultrasound contrast agents: current status and future. Abdom Radiol (NY) 2018; 43:762-772. [PMID: 29508011 DOI: 10.1007/s00261-018-1516-1] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Microbubble ultrasound contrast agents (UCAs) were recently approved by the Food and Drug administration for non-cardiac imaging. The physical principles of UCAs, methods of administration, dosage, adverse effects, and imaging techniques both current and future are described. UCAs consist of microbubbles in suspension which strongly interact with the ultrasound beam and are readily detectable by ultrasound imaging systems. They are confined to the blood pool when administered intravenously, unlike iodinated and gadolinium contrast agents. UCAs have a proven safety record based on over two decades of use, during which they have been used in echocardiography in the U.S. and for non-cardiac imaging in the rest of the world. Adverse effects are less common with UCAs than CT/MR contrast agents. Compared to CT and MR, contrast-enhanced ultrasound has the advantages of real-time imaging, portability, and reduced susceptibility to metal and motion artifact. UCAs are not nephrotoxic and can be used in renal failure. High acoustic amplitudes can cause microbubbles to fragment in a manner that can result in short-term increases in capillary permeability or capillary rupture. These bioeffects can be beneficial and have been used to enhance drug delivery under appropriate conditions. Imaging with a mechanical index of < 0.4 preserves the microbubbles and is not typically associated with substantial bioeffects. Molecularly targeted ultrasound contrast agents are created by conjugating the microbubble shell with a peptide, antibody, or other ligand designed to target an endothelial biomarker associated with tumor angiogenesis or inflammation. These microbubbles then accumulate in the microvasculature at target sites where they can be imaged. Ultrasound contrast agents are a valuable addition to the diagnostic imaging toolkit. They will facilitate cross-sectional abdominal imaging in situations where contrast-enhanced CT and MR are contraindicated or impractical.
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Affiliation(s)
- Wui K Chong
- Department of Diagnostic Radiology, University of Texas MD Anderson Cancer Center, Unit 1473 | FCT15.5092, 1400 Pressler Street, Houston, TX, 77030, USA.
| | - Virginie Papadopoulou
- UNC-NC State Joint Department of Biomedical Engineering, Chapel Hill, NC, 27599, USA
| | - Paul A Dayton
- UNC Biomedical Research Imaging Center, Chapel Hill, NC, 27599, USA
- UNC-NC State Joint Department of Biomedical Engineering, Chapel Hill, NC, 27599, USA
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42
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Jang KW, Seol D, Ding L, Lim TH, Frank JA, Martin JA. Ultrasound-Mediated Microbubble Destruction Suppresses Melanoma Tumor Growth. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:831-839. [PMID: 29361373 PMCID: PMC5826859 DOI: 10.1016/j.ultrasmedbio.2017.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 11/29/2017] [Accepted: 12/13/2017] [Indexed: 05/23/2023]
Abstract
Melanoma is one of the most aggressive types of cancer, and its incidence has increased rapidly in the past few decades. In this study, we investigated a novel treatment approach, the use of low-intensity ultrasound (2.3 W/cm2 at 1 MHz)-mediated Optison microbubble (MB) destruction (UMMD) to treat melanoma in a flank tumor model. The effect of UMMD was first evaluated in the melanoma cell line B16 F10 (B16) in vitro and then in mice inoculated with B16 cells. MB+B16 cells were exposed to US in vitro, resulting in significant cell death proportional to duty cycle (R2 = 0.74): approximately 30%, 50%, 80% and 80% cell death at 10%, 30%, 50% and 100% DC respectively. Direct implantation of tumors with MBs, followed by sonication, resulted in retarded tumor growth and improved survival (p = 0.0106). Immunohistochemical analyses confirmed the significant changes in expression of the cell proliferation marker Ki67 (p = 0.037) and a microtubule-associated protein 2 (p = 0.048) after US + MB treatment. These results suggest that UMMD could be used as a possible treatment approach in isolated melanoma and has the potential to translate to clinical trials.
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Affiliation(s)
- Kee W Jang
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
| | - Dongrim Seol
- Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, Iowa, USA
| | - Lei Ding
- Jiangnan University Wuxi Medical School, Wuxi, Jiangsu, China
| | - Tae-Hong Lim
- Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa, USA
| | - Joseph A Frank
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA; National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
| | - James A Martin
- Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, Iowa, USA
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Bez M, Sheyn D, Tawackoli W, Avalos P, Shapiro G, Giaconi JC, Da X, David SB, Gavrity J, Awad HA, Bae HW, Ley EJ, Kremen TJ, Gazit Z, Ferrara KW, Pelled G, Gazit D. In situ bone tissue engineering via ultrasound-mediated gene delivery to endogenous progenitor cells in mini-pigs. Sci Transl Med 2018; 9:9/390/eaal3128. [PMID: 28515335 DOI: 10.1126/scitranslmed.aal3128] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 02/08/2017] [Accepted: 04/14/2017] [Indexed: 12/20/2022]
Abstract
More than 2 million bone-grafting procedures are performed each year using autografts or allografts. However, both options carry disadvantages, and there remains a clear medical need for the development of new therapies for massive bone loss and fracture nonunions. We hypothesized that localized ultrasound-mediated, microbubble-enhanced therapeutic gene delivery to endogenous stem cells would induce efficient bone regeneration and fracture repair. To test this hypothesis, we surgically created a critical-sized bone fracture in the tibiae of Yucatán mini-pigs, a clinically relevant large animal model. A collagen scaffold was implanted in the fracture to facilitate recruitment of endogenous mesenchymal stem/progenitor cells (MSCs) into the fracture site. Two weeks later, transcutaneous ultrasound-mediated reporter gene delivery successfully transfected 40% of cells at the fracture site, and flow cytometry showed that 80% of the transfected cells expressed MSC markers. Human bone morphogenetic protein-6 (BMP-6) plasmid DNA was delivered using ultrasound in the same animal model, leading to transient expression and secretion of BMP-6 localized to the fracture area. Micro-computed tomography and biomechanical analyses showed that ultrasound-mediated BMP-6 gene delivery led to complete radiographic and functional fracture healing in all animals 6 weeks after treatment, whereas nonunion was evident in control animals. Collectively, these findings demonstrate that ultrasound-mediated gene delivery to endogenous mesenchymal progenitor cells can effectively treat nonhealing bone fractures in large animals, thereby addressing a major orthopedic unmet need and offering new possibilities for clinical translation.
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Affiliation(s)
- Maxim Bez
- Skeletal Biotech Laboratory, Hadassah Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem 91120, Israel.,Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Dmitriy Sheyn
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Wafa Tawackoli
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Pablo Avalos
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Galina Shapiro
- Skeletal Biotech Laboratory, Hadassah Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem 91120, Israel
| | - Joseph C Giaconi
- Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Xiaoyu Da
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Shiran Ben David
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jayne Gavrity
- Department of Biomedical Engineering and the Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Hani A Awad
- Department of Biomedical Engineering and the Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Hyun W Bae
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Eric J Ley
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Thomas J Kremen
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Department of Orthopedics, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Zulma Gazit
- Skeletal Biotech Laboratory, Hadassah Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem 91120, Israel.,Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Orthopedics, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Katherine W Ferrara
- Department of Biomedical Engineering, University of California, Davis, 451 Health Sciences Drive, Davis, CA 95616, USA
| | - Gadi Pelled
- Skeletal Biotech Laboratory, Hadassah Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem 91120, Israel.,Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Dan Gazit
- Skeletal Biotech Laboratory, Hadassah Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem 91120, Israel. .,Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Orthopedics, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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44
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Cryo-EM Visualization of Lipid and Polymer-Stabilized Perfluorocarbon Gas Nanobubbles - A Step Towards Nanobubble Mediated Drug Delivery. Sci Rep 2017; 7:13517. [PMID: 29044154 PMCID: PMC5647366 DOI: 10.1038/s41598-017-13741-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/27/2017] [Indexed: 02/02/2023] Open
Abstract
Gas microbubbles stabilized with lipids, surfactants, proteins and/or polymers are widely used clinically as ultrasound contrast agents. Because of their large 1-10 µm size, applications of microbubbles are confined to the blood vessels. Accordingly, there is much interest in generating nanoscale echogenic bubbles (nanobubbles), which can enable new uses of ultrasound contrast agents in molecular imaging and drug delivery, particularly for cancer applications. While the interactions of microbubbles with ultrasound have been widely investigated, little is known about the activity of nanobubbles under ultrasound exposure. In this work, we demonstrate that cryo-electron microscopy (cryo-EM) can be used to image nanoscale lipid and polymer-stabilized perfluorocarbon gas bubbles before and after their destruction with high intensity ultrasound. In addition, cryo-EM can be used to observe electron-beam induced dissipation of nanobubble encapsulated perfluorocarbon gas.
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45
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Davidson BP, Hodovan J, Belcik JT, Moccetti F, Xie A, Ammi AY, Lindner JR. Rest-Stress Limb Perfusion Imaging in Humans with Contrast Ultrasound Using Intermediate-Power Imaging and Microbubbles Resistant to Inertial Cavitation. J Am Soc Echocardiogr 2017; 30:503-510.e1. [PMID: 28238588 PMCID: PMC5573794 DOI: 10.1016/j.echo.2016.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Contrast-enhanced ultrasound (CEU) limb perfusion imaging is a promising approach for evaluating peripheral artery disease (PAD). However, low signal enhancement in skeletal muscle has necessitated high-power intermittent imaging algorithms, which are not clinically feasible. We hypothesized that CEU using a combination of intermediate power and a contrast agent resistant to inertial cavitation would allow real-time limb stress perfusion imaging. METHODS In normal volunteers, CEU of the calf skeletal muscle was performed on separate days with Sonazoid, Optison, or Definity. Progressive reduction in the ultrasound pulsing interval was used to assess the balance between signal enhancement and agent destruction at escalating mechanical indices (MI, 0.1-0.4). Real-time perfusion imaging at MI 0.1-0.4 using postdestructive replenishment kinetics was performed at rest and during 25 W plantar flexion contractile exercise. RESULTS For Optison, limb perfusion imaging was unreliable at rest due to very low signal enhancement generated at all MIs and was possible during exercise-induced hyperemia only at MI 0.1 due to agent destruction at higher MIs. For Definity, signal intensity progressively increased with MI but was offset by microbubble destruction, which resulted in modest signal enhancement during CEU perfusion imaging and distortion of replenishment curves at MI ≥ 0.2. For Sonazoid, there strong signal enhancement at MI ≥ 0.2, with little destruction detected only at MI 0.4. Accordingly, high signal intensity and nondistorted perfusion imaging was possible at MI 0.2-0.3 and detected an 8.0- ± 5.7-fold flow reserve. CONCLUSIONS Rest-stress limb perfusion imaging in humans with real-time CEU, which requires only seconds to perform, is possible using microbubbles with viscoelastic properties that produce strong nonlinear signal generation without destruction at intermediate acoustic pressures.
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Affiliation(s)
- Brian P Davidson
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon; Portland VA Medical Center, Portland, Oregon
| | - James Hodovan
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - J Todd Belcik
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Federico Moccetti
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Aris Xie
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Azzdine Y Ammi
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Jonathan R Lindner
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon; Oregon National Primate Research Center, Oregon Health and Science University, Portland, Oregon.
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46
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Zhang S, Cui Z, Xu T, Liu P, Li D, Shang S, Xu R, Zong Y, Niu G, Wang S, He X, Wan M. Inverse effects of flowing phase-shift nanodroplets and lipid-shelled microbubbles on subsequent cavitation during focused ultrasound exposures. ULTRASONICS SONOCHEMISTRY 2017; 34:400-409. [PMID: 27773262 DOI: 10.1016/j.ultsonch.2016.06.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/13/2016] [Accepted: 06/14/2016] [Indexed: 06/06/2023]
Abstract
This paper compared the effects of flowing phase-shift nanodroplets (NDs) and lipid-shelled microbubbles (MBs) on subsequent cavitation during focused ultrasound (FUS) exposures. The cavitation activity was monitored using a passive cavitation detection method as solutions of either phase-shift NDs or lipid-shelled MBs flowed at varying velocities through a 5-mm diameter wall-less vessel in a transparent tissue-mimicking phantom when exposed to FUS. The intensity of cavitation for the phase-shift NDs showed an upward trend with time and cavitation for the lipid-shelled MBs grew to a maximum at the outset of the FUS exposure followed by a trend of decreases when they were static in the vessel. Meanwhile, the increase of cavitation for the phase-shift NDs and decrease of cavitation for the lipid-shelled MBs had slowed down when they flowed through the vessel. During two discrete identical FUS exposures, while the normalized inertial cavitation dose (ICD) value for the lipid-shelled MB solution was higher than that for the saline in the first exposure (p-value <0.05), it decreased to almost the same level in the second exposure. For the phase-shift NDs, the normalized ICD was 0.71 in the first exposure and increased to 0.97 in the second exposure. At a low acoustic power, the normalized ICD values for the lipid-shelled MBs tended to increase with increasing velocities from 5 to 30cm/s (r>0.95). Meanwhile, the normalized ICD value for the phase-shift NDs was 0.182 at a flow velocity of 5cm/s and increased to 0.188 at a flow velocity of 15cm/s. As the flow velocity increased to 20cm/s, the normalized ICD was 0.185 and decreased to 0.178 at a flow velocity of 30cm/s. At high acoustic power, the normalized ICD values for both the lipid-shelled MBs and the phase-shift NDs increased with increasing flow velocities from 5 to 30cm/s (r>0.95). The effects of the flowing phase-shift NDs vaporized into gas bubbles as cavitation nuclei on the subsequent cavitation were inverse to those of the flowing lipid-shelled MBs destroyed after focused ultrasound exposures.
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Affiliation(s)
- Siyuan Zhang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Zhiwei Cui
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Tianqi Xu
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Pan Liu
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Dapeng Li
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Shaoqiang Shang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Ranxiang Xu
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Gang Niu
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, People's Republic of China
| | - Supin Wang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Xijing He
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710004, People's Republic of China
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
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47
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Mulvana H, Browning RJ, Luan Y, de Jong N, Tang MX, Eckersley RJ, Stride E. Characterization of Contrast Agent Microbubbles for Ultrasound Imaging and Therapy Research. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:232-251. [PMID: 27810805 DOI: 10.1109/tuffc.2016.2613991] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The high efficiency with which gas microbubbles can scatter ultrasound compared with the surrounding blood pool or tissues has led to their widespread employment as contrast agents in ultrasound imaging. In recent years, their applications have been extended to include super-resolution imaging and the stimulation of localized bio-effects for therapy. The growing exploitation of contrast agents in ultrasound and in particular these recent developments have amplified the need to characterize and fully understand microbubble behavior. The aim in doing so is to more fully exploit their utility for both diagnostic imaging and potential future therapeutic applications. This paper presents the key characteristics of microbubbles that determine their efficacy in diagnostic and therapeutic applications and the corresponding techniques for their measurement. In each case, we have presented information regarding the methods available and their respective strengths and limitations, with the aim of presenting information relevant to the selection of appropriate characterization methods. First, we examine methods for determining the physical properties of microbubble suspensions and then techniques for acoustic characterization of both suspensions and single microbubbles. The next section covers characterization of microbubbles as therapeutic agents, including as drug carriers for which detailed understanding of their surface characteristics and drug loading capacity is required. Finally, we discuss the attempts that have been made to allow comparison across the methods employed by various groups to characterize and describe their microbubble suspensions and promote wider discussion and comparison of microbubble behavior.
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48
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Hayashi R, Allen JS, Chitnis PV, Mamou J, Ketterling JA. Subharmonic Response of Polymer Contrast Agents Based on the Empirical Mode Decomposition. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:2107-2113. [PMID: 27913328 DOI: 10.1109/tuffc.2016.2615047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The subharmonic threshold for ultrasound contrast agents has been defined as a 20-25 dB difference between the fundamental and subharmonic (2/1) spectral components of the backscatter signal. However, this Fourier-based criterion assumes a linear time-invariant signal. A more appropriate criterion for short cycle and frequency-modulated waveforms is proposed with an adaptive signal-processing approach based on the empirical mode decomposition (EMD) method. The signal is decomposed into an orthogonal basis known as intrinsic mode functions (IMFs) and a subharmonic threshold is defined with respect to the energy ratio of the subharmonic IMF component to that of the incident signal. The method is applied to backscatter data acquired from two polymer-shelled contrast agents, Philips (#38, mean diameter 2.0 [Formula: see text]) and Point Biomedical (#12027, mean diameter 3.9 [Formula: see text]). The acoustic backscatter signals are investigated for a single contrast agent subjected to monofrequency (20 MHz, 20 cycles) and chirp (15-25 MHz, 20 cycles) forcing for incident pressures ranging from 0.5 to 2.4 MPa. In comparison to the spectral peak difference (20 dB) criterion, the EMD method is more sensitive in determining subharmonic signals.
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49
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Raymond JL, Luan Y, Peng T, Huang SL, McPherson DD, Versluis M, de Jong N, Holland CK. Loss of gas from echogenic liposomes exposed to pulsed ultrasound. Phys Med Biol 2016; 61:8321-8339. [PMID: 27811382 DOI: 10.1088/0031-9155/61/23/8321] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The destruction of echogenic liposomes (ELIP) in response to pulsed ultrasound excitations has been studied acoustically previously. However, the mechanism underlying the loss of echogenicity due to cavitation nucleated by ELIP has not been fully clarified. In this study, an ultra-high speed imaging approach was employed to observe the destruction phenomena of single ELIP exposed to ultrasound bursts at a center frequency of 6 MHz. We observed a rapid size reduction during the ultrasound excitation in 139 out of 397 (35%) ultra- high-speed recordings. The shell dilation rate, which is defined as the microbubble wall velocity divided by the instantaneous radius, [Formula: see text] /R, was extracted from the radius versus time response of each ELIP, and was found to be correlated with the deflation. Fragmentation and surface mode vibrations were also observed and are shown to depend on the applied acoustic pressure and initial radius. Results from this study can be utilized to optimize the theranostic application of ELIP, e.g. by tuning the size distribution or the excitation frequency.
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Affiliation(s)
- Jason L Raymond
- Biomedical Engineering Program, University of Cincinnati, Cardiovascular Center 3940, 231 Albert Sabin Way, Cincinnati, OH 45267-0586, USA
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50
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Martin KH, Lindsey BD, Ma J, Nichols TC, Jiang X, Dayton PA. Ex Vivo Porcine Arterial and Chorioallantoic Membrane Acoustic Angiography Using Dual-Frequency Intravascular Ultrasound Probes. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:2294-307. [PMID: 27260246 PMCID: PMC5653969 DOI: 10.1016/j.ultrasmedbio.2016.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 02/11/2016] [Accepted: 04/08/2016] [Indexed: 05/03/2023]
Abstract
The presence of blood vessels within a developing atherosclerotic plaque has been found to be correlated with increased plaque vulnerability and ensuing cardiac events, however, detection of coronary intraplaque neovascularization poses a significant challenge in the clinic. We describe here a new in vivo intravascular ultrasound imaging method using a dual-frequency transducer to visualize contrast flow in microvessels with high specificity. This method uses a specialized transducer capable of exciting contrast agents at a low frequency (5.5 MHz) while detecting their nonlinear superhamonics at a much higher frequency (37 MHz). In vitro evaluation of the approach was performed in a microvascular phantom to produce 3-D renderings of simulated vessel patterns and to determine image quality metrics as a function of depth. Furthermore, we describe the ability of the system to detect microvessels both ex vivo using porcine arteries and in vivo using the chorioallantoic membrane of a developing chicken embryo with optical confirmation. Dual-frequency contrast-specific imaging was able to resolve vessels similar in size to those found in vulnerable atherosclerotic plaques at clinically relevant depths. The results of this study add to the support for further evaluation and translation of contrast-specific imaging in intravascular ultrasound for the detection of vulnerable plaques in atherosclerosis.
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Affiliation(s)
- K Heath Martin
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Brooks D Lindsey
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Jianguo Ma
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Timothy C Nichols
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Xiaoning Jiang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA; Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, North Carolina, USA.
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