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Rich J, Tian Z, Huang TJ. Sonoporation: Past, Present, and Future. ADVANCED MATERIALS TECHNOLOGIES 2022; 7:2100885. [PMID: 35399914 PMCID: PMC8992730 DOI: 10.1002/admt.202100885] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Indexed: 05/09/2023]
Abstract
A surge of research in intracellular delivery technologies is underway with the increased innovations in cell-based therapies and cell reprogramming. Particularly, physical cell membrane permeabilization techniques are highlighted as the leading technologies because of their unique features, including versatility, independence of cargo properties, and high-throughput delivery that is critical for providing the desired cell quantity for cell-based therapies. Amongst the physical permeabilization methods, sonoporation holds great promise and has been demonstrated for delivering a variety of functional cargos, such as biomolecular drugs, proteins, and plasmids, to various cells including cancer, immune, and stem cells. However, traditional bubble-based sonoporation methods usually require special contrast agents. Bubble-based sonoporation methods also have high chances of inducing irreversible damage to critical cell components, lowering the cell viability, and reducing the effectiveness of delivered cargos. To overcome these limitations, several novel non-bubble-based sonoporation mechanisms are under development. This review will cover both the bubble-based and non-bubble-based sonoporation mechanisms being employed for intracellular delivery, the technologies being investigated to overcome the limitations of traditional platforms, as well as perspectives on the future sonoporation mechanisms, technologies, and applications.
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Affiliation(s)
- Joseph Rich
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Zhenhua Tian
- Department of Aerospace Engineering, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Tony Jun Huang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
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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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3
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Yan Y, Chen Y, Liu Z, Cai F, Niu W, Song L, Liang H, Su Z, Yu B, Yan F. Brain Delivery of Curcumin Through Low-Intensity Ultrasound-Induced Blood-Brain Barrier Opening via Lipid-PLGA Nanobubbles. Int J Nanomedicine 2021; 16:7433-7447. [PMID: 34764649 PMCID: PMC8575349 DOI: 10.2147/ijn.s327737] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 10/08/2021] [Indexed: 12/12/2022] Open
Abstract
Background Parkinson's disease (PD) is a progressive neurodegenerative disorder. Owing to the presence of blood-brain barrier (BBB), conventional pharmaceutical agents are difficult to the diseased nuclei and exert their action to inhibit or delay the progress of PD. Recent literatures have demonstrated that curcumin shows the great potential to treat PD. However, its applications are still difficult in vivo due to its poor druggability and low bioavailability through the BBB. Methods Melt-crystallization methods were used to improve the solubility of curcumin, and curcumin-loaded lipid-PLGA nanobubbles (Cur-NBs) were fabricated through encapsulating the curcumin into the cavity of lipid-PLGA nanobubbles. The bubble size, zeta potentials, ultrasound imaging capability and drug encapsulation efficiency of the Cur-NBs were characterized by a series of analytical methods. Low-intensity focused ultrasound (LIFU) combined with Cur-NB was used to open the BBB to facilitate curcumin delivery into the deep brain of PD mice, followed by behavioral evaluation for the treatment efficacy. Results The solubility of curcumin was improved by melt-crystallization methods, with 2627-fold higher than pure curcumin. The resulting Cur-NBs have a nanoscale size about 400 nm and show excellent contrast imaging performance. Curcumin drugs encapsulated into Cur-NBs could be effectively released when Cur-NBs were irradiated by LIFU at the optimized acoustic pressure, achieving 30% cumulative release rate within 6 h. Importantly, Cur-NBs combined with LIFU can open the BBB and locally deliver the curcumin into the deep-seated brain nuclei, significantly enhancing efficacy of curcumin in the Parkinson C57BL/6J mice model in comparison with only Cur-NBs and LIFU groups. Conclusion In this work, we greatly improved the solubility of curcumin and developed Cur-NBs for brain delivery of curcumin against PD through combining with LIFU-mediating BBB. Cur-NBs provide a platform for these potential drugs which are difficult to cross the BBB to treat PD disease or other central nervous system (CNS) diseases.
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Affiliation(s)
- Yiran Yan
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Yan Chen
- Department of Ultrasonic Diagnosis, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Zhongxun Liu
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Feiyan Cai
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, People's Republic of China
| | - Wanting Niu
- VA Boston Healthcare System, Boston, MA, 02130, USA.,Department of Orthopedics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Liming Song
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Haifeng Liang
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Zhiwen Su
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Bo Yu
- Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Fei Yan
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, People's Republic of China
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Keller SB, Sheeran PS, Averkiou MA. Cavitation Therapy Monitoring of Commercial Microbubbles With a Clinical Scanner. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:1144-1154. [PMID: 33112743 DOI: 10.1109/tuffc.2020.3034532] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to monitor cavitation activity during ultrasound and microbubble-mediated procedures is of high clinical value. However, there has been little reported literature comparing the cavitation characteristics of different clinical microbubbles, nor have current clinical scanners been used to perform passive cavitation detection in real time. The goal of this work was to investigate and characterize standard microbubble formulations (Optison, Sonovue, Sonazoid, and a custom microbubble made with similar components as Definity) with a custom passive cavitation detector (two confocal single-element focused transducers) and with a Philips EPIQ scanner with a C5-1 curvilinear probe passively listening. We evaluated three different methods for investigating cavitation thresholds, two from previously reported work and one developed in this work. For all three techniques, it was observed that the inertial cavitation thresholds were between 0.1 and 0.3 MPa for all agents when detected with both systems. Notably, we found that most microbubble formulations in bulk solution behaved generally similarly, with some differences. We show that these characteristics and thresholds are maintained when using a diagnostic ultrasound system for detecting cavitation activity. We believe that a systematic evaluation of the frequency response of the cavitation activity of different microbubbles in order to inform real-time therapy monitoring using a clinical ultrasound device could make an immediate clinical impact.
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McMahon D, Lassus A, Gaud E, Jeannot V, Hynynen K. Microbubble formulation influences inflammatory response to focused ultrasound exposure in the brain. Sci Rep 2020; 10:21534. [PMID: 33299094 PMCID: PMC7725832 DOI: 10.1038/s41598-020-78657-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/27/2020] [Indexed: 12/14/2022] Open
Abstract
Focused ultrasound and microbubble (FUS + MB)-mediated blood-brain barrier (BBB) permeability enhancement can facilitate targeted brain-drug delivery. While controlling the magnitude of BBB permeability enhancement is necessary to limit tissue damage, little work has attempted to decouple these concepts. This work investigated the relationship between BBB permeability enhancement and the relative transcription of inflammatory mediators 4 h following sonication. Three microbubble formulations, Definity, BG8774, and MSB4, were compared, with the dose of each formulation normalized to gas volume. While changes in the transcription of key proinflammatory mediators, such as Il1b, Ccl2, and Tnf, were correlated to the magnitude of BBB permeability enhancement, these correlations were not independent of microbubble formulation; microbubble size distribution may play an important role, as linear regression analyses of BBB permeability magnitude versus differential gene expression for these proinflammatory mediators revealed significantly greater slopes for MSB4, a monodisperse microbubble with mean diameter of 4 μm, compared to Definity or BG8774, both polydisperse microbubbles with mean diameters below 2 μm. Additionally, the function of an acoustic feedback control algorithm, based on the detection threshold of ultraharmonic emissions, was assessed. While this control strategy was effective in limiting both wideband emissions and red blood cell extravasation, microbubble formulation was found to influence the magnitude of BBB leakage and correlations to acoustic emissions. This work demonstrates that while the initial magnitude of FUS + MB-mediated BBB permeability enhancement has a clear influence on the subsequent inflammatory responses, microbubble characteristics influence these relationships and must also be considered.
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Affiliation(s)
- Dallan McMahon
- Physical Science Platform, Sunnybrook Research Institute, Toronto, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, Canada.
| | - Anne Lassus
- Bracco Suisse S.A., Plan-les-Ouates, Switzerland
| | | | | | - Kullervo Hynynen
- Physical Science Platform, Sunnybrook Research Institute, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
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Ketterling JA, Silverman RH. High-Frequency Multipulse, Plane-Wave Acoustic Contrast Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:934-942. [PMID: 31841408 PMCID: PMC7195994 DOI: 10.1109/tuffc.2019.2960211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Multipulse (MP) ultrasound contrast agent (UCA) imaging is a method to increase the contrast-to-background (CBR) ratio in regions of blood flow. Plane-wave imaging allows high frame rates, and with high-frequency ultrasound, fine-spatial and temporal resolution. MP and plane-wave imaging have not been applied to high-frequency ultrasound. Here, an 18-MHz linear array was employed to implement the MP methods of pulse inversion (PI) and amplitude modulation (AM) using high-speed, multiangle, compound plane-wave imaging. A flow of the UCA DEFINITY© at a dilution ratio of 2000:1 circulating through a 2-mm-diameter flow channel in a tissue-mimicking phantom was used to characterize CBR and compared with cases of standard, multiangle compound plane-wave imaging. The relative improvement of PI and AM versus standard plane-wave imaging ranged from 5 to 10 dB. The CBR was observed to be stable over a 60-min time duration for a 2000:1 dilution ratio and a 2000:1 dilution ratio provided an optimal CBR.
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Burgess MT, Porter TM. Control of Acoustic Cavitation for Efficient Sonoporation with Phase-Shift Nanoemulsions. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:846-858. [PMID: 30638968 PMCID: PMC8859868 DOI: 10.1016/j.ultrasmedbio.2018.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 11/20/2018] [Accepted: 12/03/2018] [Indexed: 05/18/2023]
Abstract
Acoustic cavitation can be used to temporarily disrupt cell membranes for intracellular delivery of large biomolecules. Termed sonoporation, the ability of this technique for efficient intracellular delivery (i.e., >50% of initial cell population showing uptake) while maintaining cell viability (i.e., >50% of initial cell population viable) has proven to be very difficult. Here, we report that phase-shift nanoemulsions (PSNEs) function as inertial cavitation nuclei for improvement of sonoporation efficiency. The interplay between ultrasound frequency, resultant microbubble dynamics and sonoporation efficiency was investigated experimentally. Acoustic emissions from individual microbubbles nucleated from PSNEs were captured using a broadband passive cavitation detector during and after acoustic droplet vaporization with short pulses of ultrasound at 1, 2.5 and 5 MHz. Time domain features of the passive cavitation detector signals were analyzed to estimate the maximum size (Rmax) of the microbubbles using the Rayleigh collapse model. These results were then applied to sonoporation experiments to test if uptake efficiency is dependent on maximum microbubble size before inertial collapse. Results indicated that at the acoustic droplet vaporization threshold, Rmax was approximately 61.7 ± 5.2, 24.9 ± 2.8, and 12.4 ± 2.1 μm at 1, 2.5 and 5 MHz, respectively. Sonoporation efficiency increased at higher frequencies, with efficiencies of 39.5 ± 13.7%, 46.6 ± 3.28% and 66.8 ± 5.5% at 1, 2.5 and 5 MHz, respectively. Excessive cellular damage was seen at lower frequencies because of the erosive effects of highly energetic inertial cavitation. These results highlight the importance of acoustic cavitation control in determining the outcome of sonoporation experiments. In addition, PSNEs may serve as tailorable inertial cavitation nuclei for other therapeutic ultrasound applications.
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Affiliation(s)
- Mark T Burgess
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts, USA
| | - Tyrone M Porter
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts, USA; Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA.
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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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Rich KT, Mast TD. Accuracy of a bistatic scattering substitution technique for calibration of focused receivers. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:EL469-73. [PMID: 26627816 PMCID: PMC4636500 DOI: 10.1121/1.4935080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A recent method for calibrating single-element, focused passive cavitation detectors (PCD) compares bistatic scattering measurements by the PCD and a reference hydrophone. Here, effects of scatterer properties and PCD size on frequency-dependent receive calibration accuracy are investigated. Simulated scattering from silica and polystyrene spheres was compared for small hydrophone and spherically focused PCD receivers to assess the achievable calibration accuracy as a function of frequency, scatterer size, and PCD size. Good agreement between measurements was found when the scatterer diameter was sufficiently smaller than the focal beamwidth of the PCD; this relationship was dependent on the scatterer material. For conditions that result in significant disagreement between measurements, the numerical methods described here can be used to correct experimental calibrations.
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Affiliation(s)
- Kyle T Rich
- Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio 45267, USA ,
| | - T Douglas Mast
- Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio 45267, USA ,
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Gauthier M, Yin Q, Cheng J, O'Brien WD. Design of Albumin-Coated Microbubbles Loaded With Polylactide Nanoparticles. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2015; 34:1363-72. [PMID: 26206822 PMCID: PMC4536807 DOI: 10.7863/ultra.34.8.1363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 11/19/2014] [Indexed: 03/24/2024]
Abstract
OBJECTIVES A protocol was designed to produce albumin-coated microbubbles (MBs) loaded with functionalized polylactide (PLA) nanoparticles (NPs) for future drug delivery studies. METHODS Microbubbles resulted from the sonication of 5% bovine serum albumin and 15% dextrose solution. Functionalized NPs were produced by mixing fluorescent PLA and PLA-polyethylene glycol-carboxylate conjugates. Nanoparticle-loaded MBs resulted from the covalent conjugation of functionalized NPs and MBs. Three NP/MB volume ratios (1/1, 1/10, and 1/100) and unloaded MBs were produced and compared. Statistical evaluations were based on quantitative analysis of 3 parameters at 4 time points (1, 4, 5, and 6 days post MB fabrication): MB diameter using a circle detection routine based on the Hough transform, MB number density using a hemocytometer, and NP-loading yield based on MB counts from fluorescence and light microscopic images. Loading capacity of the albumin-coated MBs was evaluated by fluorescence. RESULTS Loaded MB sizes were stable over 6 days after production and were not significantly different from that of time-matched unloaded MBs. Number density evaluation showed that only 1/1 NP/MB volume ratio and unloaded MB number densities were stable over time, and that the 1/1 MB number density evaluated at each time point was not significantly different from that of unloaded MBs. The 1/10 and 1/100 NP/MB volume ratios had unstable number densities that were significantly different from that of unloaded MBs (P < .05). Fluorescence evaluation suggested that 1/1 MBs had a higher NP-loading yield than 1/10 and 1/100 MBs. Quantitative loading evaluation suggested that the 1/1 MBs had a loading capacity of 3700 NPs/MB. CONCLUSIONS A protocol was developed to load albumin MBs with functionalized PLA NPs for further drug delivery studies. The 1/1 NP/MB volume ratio appeared to be the most efficient to produce stable loaded MBs with a loading capacity of 3700 NPs/MB.
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Affiliation(s)
- Marianne Gauthier
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA.
| | - Qian Yin
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA
| | - Jianjun Cheng
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA
| | - William D O'Brien
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA
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Lindsey BD, Rojas JD, Dayton PA. On the relationship between microbubble fragmentation, deflation and broadband superharmonic signal production. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:1711-25. [PMID: 25766572 PMCID: PMC4778426 DOI: 10.1016/j.ultrasmedbio.2014.12.668] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 05/19/2023]
Abstract
Acoustic angiography imaging of microbubble contrast agents uses the superharmonic energy produced from excited microbubbles and enables high-contrast, high-resolution imaging. However, the exact mechanism by which broadband harmonic energy is produced is not fully understood. To elucidate the role of microbubble shell fragmentation in superharmonic signal production, simultaneous optical and acoustic measurements were performed on individual microbubbles at transmit frequencies from 1.75 to 3.75 MHz and pressures near the shell fragmentation threshold for microbubbles of varying diameter. High-amplitude, broadband superharmonic signals were produced with shell fragmentation, whereas weaker signals (approximately 25% of peak amplitude) were observed in the presence of shrinking bubbles. Furthermore, when populations of stationary microbubbles were imaged with a dual-frequency ultrasound imaging system, a sharper decline in image intensity with respect to frame number was observed for 1-μm bubbles than for 4-μm bubbles. Finally, in a study of two rodents, increasing frame rate from 4 to 7 Hz resulted in decreases in mean steady-state image intensity of 27% at 1000 kPa and 29% at 1300 kPa. Although the existence of superharmonic signals when bubbles shrink has the potential to prolong the imaging efficacy of microbubbles, parameters such as frame rate and peak pressure must be balanced with expected re-perfusion rate to maintain adequate contrast during in vivo imaging.
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Affiliation(s)
- Brooks D Lindsey
- Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill and North Carolina State University, Raleigh, North Carolina, USA
| | - Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill and North Carolina State University, Raleigh, North Carolina, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill and North Carolina State University, Raleigh, North Carolina, USA.
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12
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Choi H, Popovics JS. NDE application of ultrasonic tomography to a full-scale concrete structure. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2015; 62:1076-1085. [PMID: 26067042 DOI: 10.1109/tuffc.2014.006962] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Newly developed ultrasonic imaging technology for large concrete elements, based on tomographic reconstruction, is presented. The developed 3-D internal images (velocity tomograms) are used to detect internal defects (polystyrene foam and pre-cracked concrete prisms) that represent structural damage within a large steel reinforced concrete element. A hybrid air-coupled/contact transducer system is deployed. Electrostatic air-coupled transducers are used to generate ultrasonic energy and contact accelerometers are attached on the opposing side of the concrete element to detect the ultrasonic pulses. The developed hybrid testing setup enables collection of a large amount of high-quality, through-thickness ultrasonic data without surface preparation to the concrete. The algebraic reconstruction technique is used to reconstruct p-wave velocity tomograms from the obtained time signal data. A comparison with a one-sided ultrasonic imaging method is presented for the same specimen. Through-thickness tomography shows some benefit over one-sided imaging for highly reinforced concrete elements. The results demonstrate that the proposed through-thickness ultrasonic technique shows great potential for evaluation of full-scale concrete structures in the field.
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13
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Wallace N, Dicker S, Lewin P, Wrenn SP. Inertial cavitation threshold of nested microbubbles. ULTRASONICS 2015; 58:67-74. [PMID: 25620709 DOI: 10.1016/j.ultras.2014.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Cavitation of ultrasound contrast agents (UCAs) promotes both beneficial and detrimental bioeffects in vivo (Radhakrishnan et al., 2013) [1]. The ability to determine the inertial cavitation threshold of UCA microbubbles has potential application in contrast imaging, development of therapeutic agents, and evaluation of localized effects on the body (Ammi et al., 2006) [2]. This study evaluates a novel UCA and its inertial cavitation behavior as determined by a home built cavitation detection system. Two 2.25 MHz transducers are placed at a 90° angle to one another where one transducer is driven by a high voltage pulser and the other transducer receives the signal from the oscillating microbubble. The sample chamber is placed in the overlap of the focal region of the two transducers where the microbubbles are exposed to a pulser signal consisting of 600 pulse trains per experiment at a pulse repetition frequency of 5 Hz where each train has four pulses of four cycles. The formulation being analyzed is comprised of an SF6 microbubble coated by a DSPC PEG-3000 monolayer nested within a poly-lactic acid (PLA) spherical shell. The effect of varying shell diameters and microbubble concentration on cavitation threshold profile for peak negative pressures ranging from 50 kPa to 2 MPa are presented and discussed in this paper. The nesting shell decreases inertial cavitation events from 97.96% for an un-nested microbubble to 19.09% for the same microbubbles nested within a 2.53 μm shell. As shell diameter decreases, the percentage of inertially cavitating microbubbles also decreases. For nesting formulations with average outer capsule diameters of 20.52, 14.95, 9.95, 5.55, 2.53, and 1.95 μm, the percentage of sample destroyed at 1 MPa was 51.02, 38.94, 33.25, 25.27, 19.09, and 5.37% respectively.
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Affiliation(s)
- N Wallace
- Department of Chemical Engineering, Drexel University, Philadelphia, PA, USA
| | - S Dicker
- Department of Chemical Engineering, Drexel University, Philadelphia, PA, USA
| | - Peter Lewin
- Department of Chemical Engineering, Drexel University, Philadelphia, PA, USA
| | - S P Wrenn
- Department of Chemical Engineering, Drexel University, Philadelphia, PA, USA.
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Lindsey BD, Rojas JD, Martin KH, Shelton SE, Dayton PA. Acoustic characterization of contrast-to-tissue ratio and axial resolution for dual-frequency contrast-specific acoustic angiography imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2014; 61:1668-87. [PMID: 25265176 PMCID: PMC8375273 DOI: 10.1109/tuffc.2014.006466] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Recently, dual-frequency transducers have enabled high-spatial-resolution and high-contrast imaging of vasculature with minimal tissue artifacts by transmitting at a low frequency and receiving broadband superharmonic echoes scattered by microbubble contrast agents. In this work, we examine the imaging parameters for optimizing contrast-to-tissue ratio (CTR) for dual-frequency imaging and the relationship with spatial resolution. Confocal piston transducers are used in a water bath setup to measure the SNR, CTR, and axial resolution for ultrasound imaging of nonlinear scattering of microbubble contrast agents when transmitting at a lower frequency (1.5 to 8 MHz) and receiving at a higher frequency (7.5 to 25 MHz). Parameters varied include the frequency and peak negative pressure of transmitted waves, center frequency of the receiving transducer, microbubble concentration, and microbubble size. CTR is maximized at the lowest transmission frequencies but would be acceptable for imaging in the 1.5 to 3.5 MHz range. At these frequencies, CTR is optimized when a receiving transducer with a center frequency of 10 MHz is used, with the maximum CTR of 25.5 dB occurring when transmitting at 1.5 MHz with a peak negative pressure of 1600 kPa and receiving with a center frequency of 10 MHz. Axial resolution is influenced more heavily by the receiving center frequency, with a weak decrease in measured pulse lengths associated with increasing transmit frequency. A microbubble population containing predominately 4-μm-diameter bubbles yielded the greatest CTR, followed by 1- and then 2-μm bubbles. Varying concentration showed little effect over the tested parameters. CTR dependence on transmit frequency and peak pressure were confirmed through in vivo imaging in two rodents. These findings may lead to improved imaging of vascular remodeling in superficial or luminal cancers such as those of the breast, prostate, and colon.
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15
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King DA, O’Brien WD. Quantitative analysis of ultrasound contrast agent postexcitation collapse. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2014; 61:1237-1241. [PMID: 24960713 PMCID: PMC4123746 DOI: 10.1109/tuffc.2014.3023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An empirically based peak-detection technique is described for statistically analyzing single ultrasound contrast agent collapses. It is shown that microbubbles with postexcitation collapse initially exhibit a stronger principal response on average than those without postexcitation, and that lower insonifying frequencies lead to postexcitation signals which have greater separation from their principal response and persist through more rebounds.
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Affiliation(s)
- Daniel A. King
- Department of Mathematical Sciences, Eastern Mennonite University, Harrisonburg, VA
| | - William D. O’Brien
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL
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16
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Sheeran PS, Matsunaga TO, Dayton PA. Phase change events of volatile liquid perfluorocarbon contrast agents produce unique acoustic signatures. Phys Med Biol 2013; 59:379-401. [PMID: 24351961 DOI: 10.1088/0031-9155/59/2/379] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Phase-change contrast agents (PCCAs) provide a dynamic platform to approach problems in medical ultrasound (US). Upon US-mediated activation, the liquid core vaporizes and expands to produce a gas bubble ideal for US imaging and therapy. In this study, we demonstrate through high-speed video microscopy and US interrogation that PCCAs composed of highly volatile perfluorocarbons (PFCs) exhibit unique acoustic behavior that can be detected and differentiated from standard microbubble contrast agents. Experimental results show that when activated with short pulses PCCAs will over-expand and undergo unforced radial oscillation while settling to a final bubble diameter. The size-dependent oscillation phenomenon generates a unique acoustic signal that can be passively detected in both time and frequency domain using confocal piston transducers with an 'activate high' (8 MHz, 2 cycles), 'listen low' (1 MHz) scheme. Results show that the magnitude of the acoustic 'signature' increases as PFC boiling point decreases. By using a band-limited spectral processing technique, the droplet signals can be isolated from controls and used to build experimental relationships between concentration and vaporization pressure. The techniques shown here may be useful for physical studies as well as development of droplet-specific imaging techniques.
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Affiliation(s)
- Paul S Sheeran
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC 27599, USA
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17
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Threlfall G, Wu HJ, Li K, Aldham B, Scoble J, Sutalo ID, Raicevic A, Pontes-Braz L, Lee B, Schneider-Kolsky M, Ooi A, Coia G, Manasseh R. Quantitative guidelines for the prediction of ultrasound contrast agent destruction during injection. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:1838-1847. [PMID: 23849383 DOI: 10.1016/j.ultrasmedbio.2013.04.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 04/08/2013] [Accepted: 04/21/2013] [Indexed: 06/02/2023]
Abstract
Experiments and theory were undertaken on the destruction of ultrasound contrast agent microbubbles on needle injection, with the aim of predicting agent loss during in vivo studies. Agents were expelled through a variety of syringe and needle combinations, subjecting the microbubbles to a range of pressure drops. Imaging of the bubbles identified cases where bubbles were destroyed and the extent of destruction. Fluid-dynamic calculations determined the pressure drop for each syringe and needle combination. It was found that agent destruction occurred at a critical pressure drop that depended only on the type of microbubble. Protein-shelled microbubbles (sonicated bovine serum albumin) were virtually all destroyed above their critical pressure drop of 109 ± 7 kPa Two types of lipid-shelled microbubbles were found to have a pressure drop threshold above which more than 50% of the microbubbles were destroyed. The commercial lipid-shelled agent Definity was found to have a critical pressure drop for destruction of 230 ± 10 kPa; for a previously published lipid-shelled agent, this value was 150 ± 40 kPa. It is recommended that attention to the predictions of a simple formula could preclude unnecessary destruction of microbubble contrast agent during in vivo injections. This approach may also preclude undesirable release of drug or gene payloads in targeted microbubble therapies. Example values of appropriate injection rates for various agents and conditions are given.
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Affiliation(s)
- Greg Threlfall
- CSIRO Materials Science and Engineering, Highett, Melbourne, Australia
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18
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Gauthier M, King DA, O'Brien WD. Evaluation of the temporal stability of Definity using double passive cavitation detection. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2013; 32:1535-7. [PMID: 23980212 PMCID: PMC3938207 DOI: 10.7863/ultra.32.9.1535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Affiliation(s)
- Marianne Gauthier
- Bioacoustics Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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19
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Kim HC, Al-Mahrouki A, Gorjizadeh A, Karshafian R, Czarnota GJ. Effects of biophysical parameters in enhancing radiation responses of prostate tumors with ultrasound-stimulated microbubbles. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:1376-1387. [PMID: 23643061 DOI: 10.1016/j.ultrasmedbio.2013.01.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 01/18/2013] [Accepted: 01/21/2013] [Indexed: 06/02/2023]
Abstract
We show here that ultrasound-stimulated microbubbles can enhance cell death within tumors when combined with radiation. The aim of this study was to investigate how different ultrasound parameters, different microbubble concentrations and different radiation doses interact to enhance cell death. Prostate xenograft tumors (PC-3) in severe combined immunodeficiency mice were subjected to ultrasound treatment at various peak negative pressures (250, 570 and 750 kPa) at a center frequency of 500 kHz, different microbubble concentrations (8, 80 and 1000 μL/kg) and different radiation doses (0, 2 and 8 Gy). Twenty-four hours after treatment, tumors were excised and assessed for cell death. Histologic analyses revealed that increases in radiation dose, microbubble concentration and ultrasound pressure promoted apoptotic cell death and disruption within tumors by as much as 21%, 30% and 43%, respectively. Comparable increases in ceramide, a cell death mediator, were identified using immunohistochemistry. We also show here that even clinically used microbubble concentrations combined with ultrasound can induce significant enhancement of cell death.
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Affiliation(s)
- Hyunjung Christina Kim
- Department of Medical Biophysics, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
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20
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Gauthier M, King D, O'Brien W. Influence of microbubble size on postexcitation collapse thresholds for single ultrasound contrast agents using double passive cavitation detection. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:877-879. [PMID: 23661121 PMCID: PMC3927843 DOI: 10.1109/tuffc.2013.2644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
For the first time, and using an acoustical method, it has been shown experimentally that the inertial cavitation threshold pressure of an albumin-shelled microbubble is significantly correlated with its initial size.
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21
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Wrenn SP, Dicker SM, Small EF, Dan NR, Mleczko M, Schmitz G, Lewin PA. Bursting bubbles and bilayers. Am J Cancer Res 2012; 2:1140-59. [PMID: 23382772 PMCID: PMC3563150 DOI: 10.7150/thno.4305] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 06/18/2012] [Indexed: 11/13/2022] Open
Abstract
This paper discusses various interactions between ultrasound, phospholipid monolayer-coated gas bubbles, phospholipid bilayer vesicles, and cells. The paper begins with a review of microbubble physics models, developed to describe microbubble dynamic behavior in the presence of ultrasound, and follows this with a discussion of how such models can be used to predict inertial cavitation profiles. Predicted sensitivities of inertial cavitation to changes in the values of membrane properties, including surface tension, surface dilatational viscosity, and area expansion modulus, indicate that area expansion modulus exerts the greatest relative influence on inertial cavitation. Accordingly, the theoretical dependence of area expansion modulus on chemical composition - in particular, poly (ethylene glyclol) (PEG) - is reviewed, and predictions of inertial cavitation for different PEG molecular weights and compositions are compared with experiment. Noteworthy is the predicted dependence, or lack thereof, of inertial cavitation on PEG molecular weight and mole fraction. Specifically, inertial cavitation is predicted to be independent of PEG molecular weight and mole fraction in the so-called mushroom regime. In the “brush” regime, however, inertial cavitation is predicted to increase with PEG mole fraction but to decrease (to the inverse 3/5 power) with PEG molecular weight. While excellent agreement between experiment and theory can be achieved, it is shown that the calculated inertial cavitation profiles depend strongly on the criterion used to predict inertial cavitation. This is followed by a discussion of nesting microbubbles inside the aqueous core of microcapsules and how this significantly increases the inertial cavitation threshold. Nesting thus offers a means for avoiding unwanted inertial cavitation and cell death during imaging and other applications such as sonoporation. A review of putative sonoporation mechanisms is then presented, including those involving microbubbles to deliver cargo into a cell, and those - not necessarily involving microubbles - to release cargo from a phospholipid vesicle (or reverse sonoporation). It is shown that the rate of (reverse) sonoporation from liposomes correlates with phospholipid bilayer phase behavior, liquid-disordered phases giving appreciably faster release than liquid-ordered phases. Moreover, liquid-disordered phases exhibit evidence of two release mechanisms, which are described well mathematically by enhanced diffusion (possibly via dilation of membrane phospholipids) and irreversible membrane disruption, whereas liquid-ordered phases are described by a single mechanism, which has yet to be positively identified. The ability to tune release kinetics with bilayer composition makes reverse sonoporation of phospholipid vesicles a promising methodology for controlled drug delivery. Moreover, nesting of microbubbles inside vesicles constitutes a truly “theranostic” vehicle, one that can be used for both long-lasting, safe imaging and for controlled drug delivery.
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22
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Influences of microbubble diameter and ultrasonic parameters on in vitro sonothrombolysis efficacy. J Vasc Interv Radiol 2012; 23:1677-1684.e1. [PMID: 23106936 DOI: 10.1016/j.jvir.2012.08.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 08/07/2012] [Accepted: 08/13/2012] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To quantify the effects of microbubble (MB) size, elasticity, and pulsed ultrasonic parameters on in vitro sonothrombolysis (ultrasound [US]-mediated thrombolysis) efficacy. MATERIALS AND METHODS Monodispersive MBs with diameters of 1 μm or 3 μm were exposed to pulsed US (1 MHz or 3 MHz) to lyse rabbit blood clots. Sonothrombolysis efficacy (clot mass loss) was measured as functions of MB size and concentration, ultrasonic frequency and intensity, pulse duration (PD), pulse repeat frequency (PRF), and duty factor. RESULTS Sonothrombolysis at 1 MHz was more effective using 3-μm MBs and at 3 MHz using 1-μm MBs. Sonothrombolysis was more effective at 1 MHz when≥75% of MBs remained intact, especially for 3-μm MBs; improving sonothrombolysis by increasing PRF from 100 Hz to 400 Hz at 3 MHz was associated with increasing 3-μm MB survival. However, 60% of 1-μm MBs were destroyed during maximal sonothrombolysis at 3 MHz, indicating that considerable MB collapse may be required for sonothrombolysis under these conditions. CONCLUSIONS The ability to control MB size and elasticity permits using a wide range of US parameters (eg, frequency, intensity) to produce desired levels of sonothrombolysis. Comparable, maximal sonothrombolysis efficacy was achieved at 20-fold lower intensity with 3-μm MBs (0.1W/cm(2)) than with 1-μm MBs (2.0W/cm(2)), a potential safety issue for in vivo sonothrombolysis. US parameters that maximized MB survival yielded maximal sonothrombolysis efficacy except with 1-μm MBs at 3MHz where most MBs were destroyed.
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23
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The angiogenic response is dependent on ultrasound contrast agent concentration. Vasc Cell 2012; 4:10. [PMID: 22587914 PMCID: PMC3583242 DOI: 10.1186/2045-824x-4-10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 04/14/2012] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Ultrasound (US) and ultrasound contrast agents (UCAs) provide a way to noninvasively induce targeted angiogenesis. However, there exists a lack of understanding regarding the mechanisms of this process that has impeded progress. This study sought to characterize the angiogenic response, by both exploring the role of UCA concentration ([UCA]) in bioeffect induction at 0 days post exposure (DPE) and assessing the bioeffect as a possible potentiator of angiogenesis at 5 DPE. METHODS A 1-MHz ultrasonic transducer was used to expose the gracilis muscles of Sprague Dawley rats for 5 min with a 10-μs pulse duration, 10-Hz pulse repetition frequency, and 0.7-MPa peak rarefactional acoustic pressure (pr). Four [UCA]s were tested: 0x (saline), 1×, 5×, and 10×, where 1× is 5% Definity by volume of solution. Evans blue dye (EBD) was used to quantify changes in acute vascular permeability (0 DPE), and VEGF expression was quantified at 5 DPE to support that angiogenesis had occurred. CD31 staining was used to assess capillary density at both time points. RESULTS [UCA] was a significant parameter for determining EBD leakage (permeability) and VEGF expression (p < 0.001 for both). However, [UCA] was not a significant parameter for capillary density at 0 or 5 DPE. Multiple comparisons between 0 and 5 DPE showed that only 10× [UCA] at 5 DPE was significantly different than 0 DPE, suggesting a [UCA] dependence of the angiogenic response. CONCLUSIONS This study suggests that [UCA] was a significant parameter in the induction of an angiogenic response with US and UCAs. It also suggests that rather than damage from US and UCAs, as previously speculated, a nondestructive mechanical interaction between the UCAs and vascular endothelium induces bioeffects to potentiate the angiogenic response.
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Liu Y, Yan J, Prausnitz MR. Can ultrasound enable efficient intracellular uptake of molecules? A retrospective literature review and analysis. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:876-88. [PMID: 22425381 PMCID: PMC3428263 DOI: 10.1016/j.ultrasmedbio.2012.01.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 01/08/2012] [Accepted: 01/09/2012] [Indexed: 05/09/2023]
Abstract
Most applications of therapeutic ultrasound (US) for intracellular delivery of drugs, proteins, DNA/RNA and other compounds would benefit from efficient uptake of these molecules into large numbers of cells without killing cells in the process. In this study we tested the hypothesis that efficient intracellular uptake of molecules can be achieved with high cell viability after US exposure in vitro. A search of the literature for studies with quantitative data on uptake and viability yielded 26 published papers containing 898 experimental data points. Analysis of these studies showed that just 7.7% of the data points corresponded to relatively efficient uptake (>50% of cells exhibiting uptake). Closer examination of the data showed that use of Definity US contrast agent (as opposed to Optison) and elevated sonication temperature at 37°C (as opposed to room temperature) were associated with high uptake, which we further validated through independent experiments carried out in this study. Although these factors contributed to high uptake, almost all data with efficient uptake were from studies that had not accounted for lysed cells when determining cell viability. Based on retrospective analysis of the data, we showed that not accounting for lysed cells can dramatically increase the calculated uptake efficiency. We further argue that if all the data considered in this study were re-analyzed to account for lysed cells, there would be essentially no data with efficient uptake. We therefore conclude that the literature does not support the hypothesis that efficient intracellular uptake of molecules can be achieved with high cell viability after US exposure in vitro, which poses a challenge to future applications of US that require efficient intracellular delivery.
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Affiliation(s)
- Ying Liu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA
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25
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Borrelli MJ, O'Brien WD, Bernock LJ, Williams HR, Hamilton E, Wu J, Oelze ML, Culp WC. Production of uniformly sized serum albumin and dextrose microbubbles. ULTRASONICS SONOCHEMISTRY 2012; 19:198-208. [PMID: 21689961 PMCID: PMC3152625 DOI: 10.1016/j.ultsonch.2011.05.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 03/21/2011] [Accepted: 05/15/2011] [Indexed: 05/05/2023]
Abstract
Uniformly-sized preparations with average microbubble (MB) diameters from 1 to 7 μm were produced reliably by sonicating decafluorobutane-saturated solutions of serum albumin and dextrose. Detailed protocols for producing and size-separating the MBs are presented, along with the effects that changing each production parameter (serum albumin concentration, sonication power, sonication time, etc.) had on MB size distribution and acoustic stability. These protocols can be used to produce MBs for experimental applications or serve as templates for developing new protocols that yield MBs with physical and acoustic properties better suited to specific applications. Size stability and ultrasonic performance quality control tests were developed to assure that successive MB preparations perform identically and to distinguish the physical and acoustic properties of identically sized MBs produced with different serum albumin-dextrose formulations and sonication parameters. MBs can be stored at 5 °C for protracted periods (2 weeks to one year depending on formulation).
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Affiliation(s)
- Michael J Borrelli
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 West Markham Street Slot #556, Little Rock, AR 72205, USA.
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26
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Johnson CA, Miller RJ, O'Brien WD. Ultrasound contrast agents affect the angiogenic response. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2011; 30:933-941. [PMID: 21705726 PMCID: PMC3401069 DOI: 10.7863/jum.2011.30.7.933] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVES The interaction of ultrasound contrast agents (UCAs) and ultrasound (US) provides a way to spatially and temporally target tissues. Recently, UCAs have been used therapeutically to induce localized angiogenesis. Ultrasound contrast agents, however, have been documented to induce negative bioeffects. To further understand the balance of risks and benefits of UCAs and to examine the mechanism of US-UCA-induced angiogenesis, this study explored the role of UCAs, in particular Definity (Lantheus Medical Imaging, Inc, North Billerica, MA), in producing an angiogenic response. METHODS The gracilis muscles of Sprague Dawley rats were exposed to 1-MHz US. The rats were euthanized the same day or allowed to recover for 3 or 6 days post exposure (DPE). Ultrasound peak rarefactional pressures (P(r)s) of 0.25, 0.83, 1.4, and 2.0 MPa were used while rats were infused with either saline or Definity. Assessments for angiogenesis included capillary density, inflammation, and vascular endothelial growth factor (VEGF), both acutely (0 DPE) and at 3 and 6 DPE. RESULTS The results of this study suggest that the angiogenic response is dependent on infusion media, P(r), and DPE. While capillary density did not reach significance, VEGF expression was significant for infusion media, P(r), and DPE with inflammation co-occurrence (P < .05). CONCLUSIONS These results suggest that the angiogenic response is elicited by a mechanical effect of US-UCA stimulation of VEGF that is potentially optimized when collapse occurs.
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Affiliation(s)
- Chenara A Johnson
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 405 N Mathews, Urbana, IL 61801 USA
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27
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King DA, O'Brien WD. Comparison between maximum radial expansion of ultrasound contrast agents and experimental postexcitation signal results. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 129:114-21. [PMID: 21302993 PMCID: PMC3055285 DOI: 10.1121/1.3523339] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Experimental postexcitation signal data of collapsing Definity microbubbles are compared with the Marmottant theoretical model for large amplitude oscillations of ultrasound contrast agents (UCAs). After taking into account the insonifying pulse characteristics and size distribution of the population of UCAs, a good comparison between simulated results and previously measured experimental data is obtained by determining a threshold maximum radial expansion (Rmax) to indicate the onset of postexcitation. This threshold Rmax is found to range from 3.4 to 8.0 times the initial bubble radius, R0, depending on insonification frequency. These values are well above the typical free bubble inertial cavitation threshold commonly chosen at 2R0. The close agreement between the experiment and models suggests that lipid-shelled UCAs behave as unshelled bubbles during most of a large amplitude cavitation cycle, as proposed in the Marmottant equation.
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Affiliation(s)
- Daniel A King
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green Street, Urbana, Illinois 61801, USA.
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28
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Johnson CA, Sarwate S, Miller RJ, O'Brien WD. A temporal study of ultrasound contrast agent-induced changes in capillary density. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2010; 29:1267-75. [PMID: 20733181 PMCID: PMC3069919 DOI: 10.7863/jum.2010.29.9.1267] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
OBJECTIVE The ability of ultrasound (US) and ultrasound contrast agents (UCAs) to induce angiogenesis has been explored as a means of restoring blood flow to ischemic muscle. Because UCAs demonstrate an increasing percentage of collapse cavitation with increasing US pressure (Pr), this study sought to explore the effects of a US Pr that produces 100% collapse cavitation, determine the capillary density changes, and determine the time point of angiogenic rebound in a normal animal model. METHODS Using a 1-MHz focused transducer and a peak rarefactional US Pr of 3.8 MPa, rat gracilis muscles were exposed to US, and bioeffects were assessed. Capillary density, as a measure of angiogenesis, was examined. As an additional measure, inflammatory cells were quantified via a color threshold analysis to detect the presence of CD31 and CD34 as a percentage of the total section on stained slides. Six groups (0, 3, 6, 13, 20, and 27 days postexposure [DPE]; n = 3 each) and 5 cage controls were used to characterize the angiogenic response. RESULTS Ultrasound-UCA treatment caused the capillary density to decrease acutely (0 DPE) by 70% and inflammatory cells to increase by up to 250%. The angiogenic rebound was observed at 3 DPE but did not return to control levels by 27 DPE, suggesting an incomplete healing response. CONCLUSIONS Capillary destruction and inflammation played an important role in the angiogenic response induced by US-UCA. Exposure that causes 100% collapse cavitation causes capillary destruction from which normal rats are unable to recover and suggests a nontherapeutic effect.
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Affiliation(s)
- Chenara A Johnson
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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