1
|
Mendes MIP, Coelho CDF, Schaberle FA, Moreno MJ, Calvete MJF, Arnaut LG. Nanodroplet vaporization with pulsed-laser excitation repeatedly amplifies photoacoustic signals at low vaporization thresholds. RSC Adv 2023; 13:35040-35049. [PMID: 38046627 PMCID: PMC10690495 DOI: 10.1039/d3ra05639b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/22/2023] [Indexed: 12/05/2023] Open
Abstract
Nanodroplets' explosive vaporization triggered by absorption of laser pulses produces very large volume changes. These volume changes are two orders of magnitude higher than those of thermoelastic expansion generated by equivalent laser pulses, and should generate correspondingly higher photoacoustic waves (PAW). The generation of intense PAWs is desirable in photoacoustic tomography (PAT) to increase sensitivity. The biocompatibility and simplicity of nanodroplets obtained by sonication of perfluoropentane (PFP) in an aqueous solution of bovine serum albumin (BSA) containing a dye make them particularly appealing for use as contrast agents in clinical applications of PAT. Their usefulness depends on stability and reproducible vaporization of nanodroplets (liquid PFP inside) to microbubbles (gaseous PFP inside), and reversible condensation to nanodroplets. This work incorporates porphyrins with fluorinated chains and BSA labelled with fluorescent probes in PFP nanodroplets to investigate the structure and properties of such nanodroplets. Droplets prepared with average diameters in the 400-1000 nm range vaporize when exposed to nanosecond laser pulses with fluences above 3 mJ cm-2 and resist coalescence. The fluorinated chains are likely responsible for the low vaporization threshold, ∼2.5 mJ cm-2, which was obtained from the laser fluence dependence of the photoacoustic wave amplitudes. Only ca. 10% of the droplets incorporate fluorinated porphyrins. Nevertheless, PAWs generated with nanodroplets are ten times higher than those generated by aqueous BSA solutions containing an equivalent amount of porphyrin. Remarkably, successive laser pulses result in similar amplification, indicating that the microbubbles revert back to nanodroplets at a rate faster than the laser repetition rate (10 Hz). PFP nanodroplets are promising contrast agents for PAT and their performance increases with properly designed dyes.
Collapse
Affiliation(s)
- Maria Inês P Mendes
- CQC-IMS, Chemistry Department, University of Coimbra 3004-535 Coimbra Portugal
- LaserLeap Technologies Rua Coronel Júlio Veiga Simão, Edifício B, CTCV, S/N 3025-307 Coimbra Portugal
| | - Carlos D F Coelho
- CQC-IMS, Chemistry Department, University of Coimbra 3004-535 Coimbra Portugal
| | - Fábio A Schaberle
- CQC-IMS, Chemistry Department, University of Coimbra 3004-535 Coimbra Portugal
| | - Maria João Moreno
- CQC-IMS, Chemistry Department, University of Coimbra 3004-535 Coimbra Portugal
| | - Mário J F Calvete
- CQC-IMS, Chemistry Department, University of Coimbra 3004-535 Coimbra Portugal
| | - Luis G Arnaut
- CQC-IMS, Chemistry Department, University of Coimbra 3004-535 Coimbra Portugal
| |
Collapse
|
2
|
Jandhyala S, Van Namen A, Spatarelu CP, Luke GP. EGFR-Targeted Perfluorohexane Nanodroplets for Molecular Ultrasound Imaging. NANOMATERIALS 2022; 12:nano12132251. [PMID: 35808089 PMCID: PMC9268413 DOI: 10.3390/nano12132251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 02/01/2023]
Abstract
Perfluorocarbon nanodroplets offer an alternative to gaseous microbubbles as contrast agents for ultrasound imaging. They can be acoustically activated to induce a liquid-to-gas phase transition and provide contrast in ultrasound images. In this study, we demonstrate a new strategy to synthesize antibody-conjugated perfluorohexane nanodroplet (PFHnD-Ab) ultrasound contrast agents that target cells overexpressing the epidermal growth factor receptor (EGFR). The perfluorohexane nanodroplets (PFHnD) containing a lipophilic DiD fluorescent dye were synthesized using a phospholipid shell. Antibodies were conjugated to the surface through a hydrazide-aldehyde reaction. Cellular binding was confirmed using fluorescence microscopy; the DiD fluorescence signal of the PFHnD-Ab was 5.63× and 6× greater than the fluorescence signal in the case of non-targeted PFHnDs and the EGFR blocking control, respectively. Cells were imaged in tissue-mimicking phantoms using a custom ultrasound imaging setup consisting of a high-intensity focused ultrasound transducer and linear array imaging transducer. Cells with conjugated PFHnD-Abs exhibited a significantly higher (p < 0.001) increase in ultrasound amplitude compared to cells with non-targeted PFHnDs and cells exposed to free antibody before the addition of PFHnD-Abs. The developed nanodroplets show potential to augment the use of ultrasound in molecular imaging cancer diagnostics.
Collapse
Affiliation(s)
- Sidhartha Jandhyala
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA; (S.J.); (A.V.N.); (C.-P.S.)
| | - Austin Van Namen
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA; (S.J.); (A.V.N.); (C.-P.S.)
| | - Catalina-Paula Spatarelu
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA; (S.J.); (A.V.N.); (C.-P.S.)
| | - Geoffrey P. Luke
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA; (S.J.); (A.V.N.); (C.-P.S.)
- Translational Engineering in Cancer Program, Dartmouth Cancer Center, Lebanon, NH 03756, USA
- Correspondence:
| |
Collapse
|
3
|
Zhang W, Shi Y, Abd Shukor S, Vijayakumaran A, Vlatakis S, Wright M, Thanou M. Phase-shift nanodroplets as an emerging sonoresponsive nanomaterial for imaging and drug delivery applications. NANOSCALE 2022; 14:2943-2965. [PMID: 35166273 DOI: 10.1039/d1nr07882h] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nanodroplets - emerging phase-changing sonoresponsive materials - have attracted substantial attention in biomedical applications for both tumour imaging and therapeutic purposes due to their unique response to ultrasound. As ultrasound is applied at different frequencies and powers, nanodroplets have been shown to cavitate by the process of acoustic droplet vapourisation (ADV), causing the development of mechanical forces which promote sonoporation through cellular membranes. This allows drugs to be delivered efficiently into deeper tissues where tumours are located. Recent reviews on nanodroplets are mostly focused on the mechanism of cavitation and their applications in biomedical fields. However, the chemistry of the nanodroplet components has not been discussed or reviewed yet. In this review, the commonly used materials and preparation methods of nanodroplets are summarised. More importantly, this review provides examples of variable chemistry components in nanodroplets which link them to their efficiency as ultrasound-multimodal imaging agents to image and monitor drug delivery. Finally, the drawbacks of current research, future development, and future direction of nanodroplets are discussed.
Collapse
Affiliation(s)
- Weiqi Zhang
- School of Cancer & Pharmaceutical Sciences, King's College London, UK.
| | - Yuhong Shi
- School of Cancer & Pharmaceutical Sciences, King's College London, UK.
| | | | | | - Stavros Vlatakis
- School of Cancer & Pharmaceutical Sciences, King's College London, UK.
| | - Michael Wright
- School of Cancer & Pharmaceutical Sciences, King's College London, UK.
| | - Maya Thanou
- School of Cancer & Pharmaceutical Sciences, King's College London, UK.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Namen AV, Jandhyala S, Jordan T, Luke GP. Repeated Acoustic Vaporization of Perfluorohexane Nanodroplets for Contrast-Enhanced Ultrasound Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:3497-3506. [PMID: 34191726 PMCID: PMC8667194 DOI: 10.1109/tuffc.2021.3093828] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Superheated perfluorocarbon nanodroplets are emerging ultrasound imaging contrast agents that boast biocompatible components, unique phase-change dynamics, and therapeutic loading capabilities. Upon exposure to a sufficiently high-intensity pulse of acoustic energy, the nanodroplet's perfluorocarbon core undergoes a liquid-to-gas phase change and becomes an echogenic microbubble, providing ultrasound contrast. The controllable activation leads to high-contrast images, while the small size of the nanodroplets promotes longer circulation times and better in vivo stability. One drawback, however, is that the nanodroplets can only be vaporized a single time, limiting their versatility. Recently, we and others have addressed this issue by using a perfluorohexane core, which has a boiling point above body temperature. Thus after vaporization, the microbubbles recondense back into their stable nanodroplet form. Previous work with perfluorohexane nanodroplets relied on optical activation via pulsed laser absorption of an encapsulated dye. This strategy limits the imaging depth and temporal resolution of the method. In this study, we overcome these limitations by demonstrating acoustic droplet vaporization with 1.1-MHz high-intensity focused ultrasound (HIFU). A short-duration, high-amplitude pulse of focused ultrasound provides a sufficiently strong peak negative pressure to initiate vaporization. A custom imaging sequence was developed to enable the synchronization of a HIFU transducer and a linear array imaging transducer. We show a visualization of repeated acoustic activation of perfluorohexane nanodroplets in polyacrylamide tissue-mimicking phantoms. We further demonstrate the detection of hundreds of vaporization events from individual nanodroplets with activation thresholds well below the tissue cavitation limit. Overall, this approach has the potential to result in reliable and repeatable contrast-enhanced ultrasound imaging at clinically relevant depths.
Collapse
|
6
|
Toumia Y, Miceli R, Domenici F, Heymans SV, Carlier B, Cociorb M, Oddo L, Rossi P, D'Angellilo RM, Sterpin E, D'Agostino E, Van Den Abeele K, D'hooge J, Paradossi G. Ultrasound-assisted investigation of photon triggered vaporization of poly(vinylalcohol) phase-change nanodroplets: A preliminary concept study with dosimetry perspective. Phys Med 2021; 89:232-242. [PMID: 34425514 DOI: 10.1016/j.ejmp.2021.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/08/2021] [Accepted: 08/10/2021] [Indexed: 01/24/2023] Open
Abstract
PURPOSE We investigate the vaporization of phase-change ultrasound contrast agents using photon radiation for dosimetry perspectives in radiotherapy. METHODS We studied superheated perfluorobutane nanodroplets with a crosslinked poly(vinylalcohol) shell. The nanodroplets' physico-chemical properties, and their acoustic transition have been assessed firstly. Then, poly(vinylalcohol)-perfluorobutane nanodroplets were dispersed in poly(acrylamide) hydrogel phantoms and exposed to a photon beam. We addressed the effect of several parameters influencing the nanodroplets radiation sensitivity (energy/delivered dose/dose rate/temperature). The nanodroplets-vaporization post-photon exposure was evaluated using ultrasound imaging at a low mechanical index. RESULTS Poly(vinylalcohol)-perfluorobutane nanodroplets show a good colloidal stability over four weeks and remain highly stable at temperatures up to 78 °C. Nanodroplets acoustically-triggered phase transition leads to microbubbles with diameters <10 μm and an activation threshold of mechanical index = 0.4, at 7.5 MHz. A small number of vaporization events occur post-photon exposure (6MV/15MV), at doses between 2 and 10 Gy, leading to ultrasound contrast increase up to 60% at RT. The nanodroplets become efficiently sensitive to photons when heated to a temperature of 65 °C (while remaining below the superheat limit temperature) during irradiation. CONCLUSIONS Nanodroplets' core is linked to the degree of superheat in the metastable state and plays a critical role in determining nanodroplet' stability and sensitivity to ionizing radiation, requiring higher or lower linear energy transfer vaporization thresholds. While poly(vinylalcohol)-perfluorobutane nanodroplets could be slightly activated by photons at ambient conditions, a good balance between the degree of superheat and stability will aim at optimizing the design of nanodroplets to reach high sensitivity to photons at physiological conditions.
Collapse
Affiliation(s)
- Yosra Toumia
- Department of Chemical Science and Technology, University of Rome Tor Vergata, Italy; INFN sez.Roma Tor Vergata, Italy.
| | - Roberto Miceli
- Radiotherapy Unit, Department of Oncology and Hematology, University Hospital Tor Vergata (PTV), University of Rome Tor Vergata, Italy
| | - Fabio Domenici
- Department of Chemical Science and Technology, University of Rome Tor Vergata, Italy; INFN sez.Roma Tor Vergata, Italy
| | - Sophie V Heymans
- Department of Physics, KU Leuven Campus Kulak, Kortrijk, Belgium; Department of Biomedical Engineering, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Bram Carlier
- Department of Oncology, KU Leuven, Leuven, Belgium
| | - Madalina Cociorb
- Department of Chemical Science and Technology, University of Rome Tor Vergata, Italy; DoseVue, Hasselt, Belgium
| | - Letizia Oddo
- Department of Chemical Science and Technology, University of Rome Tor Vergata, Italy
| | - Piero Rossi
- Department of Surgical Sciences, PTV, University of Rome Tor Vergata, Italy
| | - Rolando Maria D'Angellilo
- Radiotherapy Unit, Department of Oncology and Hematology, University Hospital Tor Vergata (PTV), University of Rome Tor Vergata, Italy
| | | | | | | | - Jan D'hooge
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Gaio Paradossi
- Department of Chemical Science and Technology, University of Rome Tor Vergata, Italy; INFN sez.Roma Tor Vergata, Italy
| |
Collapse
|
7
|
Sheng D, Deng L, Li P, Wang Z, Zhang Q. Perfluorocarbon Nanodroplets with Deep Tumor Penetration and Controlled Drug Delivery for Ultrasound/Fluorescence Imaging Guided Breast Cancer Therapy. ACS Biomater Sci Eng 2021; 7:605-616. [PMID: 33464814 DOI: 10.1021/acsbiomaterials.0c01333] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Danli Sheng
- Institute of Ultrasound Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P. R. China
- Department of Ultrasound, Fudan University, Shanghai Cancer Center, Shanghai 200032, China
| | - Liming Deng
- Institute of Ultrasound Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P. R. China
| | - Pan Li
- Institute of Ultrasound Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P. R. China
| | - Zhigang Wang
- Institute of Ultrasound Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P. R. China
| | - Qunxia Zhang
- Institute of Ultrasound Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P. R. China
| |
Collapse
|
8
|
|
9
|
Shin U, Kim J, Lee J, Park D, Lee C, Jung HC, Park J, Lee K, Lee MW, Kim SW, Seo J. Development of 64Cu-loaded Perfluoropentane Nanodroplet: A Potential Tumor Theragnostic Nano-carrier and Dual-Modality PET-Ultrasound Imaging Agents. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2775-2784. [PMID: 32653208 DOI: 10.1016/j.ultrasmedbio.2020.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 04/24/2020] [Accepted: 05/31/2020] [Indexed: 06/11/2023]
Abstract
The purpose of this study was to develop and preliminarily evaluate phospholipid-shelled nanodroplets (NDs) encapsulating perfluoropentane (PFP) and radioactive 64Cu as a hybrid positron emission tomography (PET)-ultrasound (US) probe. PFP NDs were fabricated by mixing liquid-phase PFP with a phospholipid solution. The 64Cu was encapsulated into the NDs in a size-controlled manner by exploiting the hydrophobicity of 64Cu-diacetyl-bis(N4-methylthiosemicarbazone) (64Cu-ATSM) using a vial mixer and an extruder. The fabricated 64Cu-loaded PFP NDs (64Cu-PFP NDs) were evaluated using in vitro/in vivo PET-computed tomography (PET-CT), US imaging and transmission electron microscopy. In the in vitro PET images, the 64Cu-PFP NDs were observed as a hot spot in the lower section of the test tube. In the acquired US images, the mean region of interest brightness values of 64Cu-PFP NDs were revealed by their strong echo image. In a tumor-bearing mouse animal model, tumor uptake of the 64Cu-PFP NDs was low, that is, approximately 65%, compared with that of only free 64Cu, as determined by PET-delayed imaging analysis. The dual-function concept of the NDs is expected to contribute to the prognosis and effectiveness of therapy by fusing the science and technology of nuclear medicine and US.
Collapse
Affiliation(s)
- Unchol Shin
- Department of Biomedical Engineering, College of Health Sciences, Yonsei University, Seoul, Republic of Korea; College of Health Sciences, Institute of Health Science, Korea University, Seoul, Republic of Korea
| | - Jungyoung Kim
- Department of Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Jiwoong Lee
- College of Health Sciences, Institute of Health Science, Korea University, Seoul, Republic of Korea
| | - Donghee Park
- Bioinfra Inc., Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Changmoon Lee
- Department of Biomedical Engineering, College of Engineering, Chonnam National University, Gwangju, Republic of Korea
| | - Hyon Chel Jung
- College of Health Sciences, Institute of Health Science, Korea University, Seoul, Republic of Korea
| | - Jiae Park
- Department of Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Kyochul Lee
- Department of Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Min Woo Lee
- College of Health Sciences, Institute of Health Science, Korea University, Seoul, Republic of Korea
| | - Suhng Wook Kim
- College of Health Sciences, Institute of Health Science, Korea University, Seoul, Republic of Korea
| | - Jongbum Seo
- Department of Biomedical Engineering, College of Health Sciences, Yonsei University, Seoul, Republic of Korea.
| |
Collapse
|
10
|
Jiang Q, Zeng Y, Xu Y, Xiao X, Liu H, Zhou B, Kong Y, Saw PE, Luo B. Ultrasound Molecular Imaging as a Potential Non-invasive Diagnosis to Detect the Margin of Hepatocarcinoma via CSF-1R Targeting. Front Bioeng Biotechnol 2020; 8:783. [PMID: 32760707 PMCID: PMC7371923 DOI: 10.3389/fbioe.2020.00783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 06/22/2020] [Indexed: 01/04/2023] Open
Abstract
Though radiofrequency ablation (RFA) is considered to be an effective treatment for hepatocellular carcinoma (HCC), but more than 30% of patients may suffer insufficient RFA (IRFA), which can promote more aggressive of the residual tumor. One possible method to counter this is to accurately identify the margin of the HCC. Colony-stimulating factor 1 receptor (CSF-1R) has been found to be restrictively expressed by tumor associated macrophages (TAMs) and monocytes which more prefer to locate at the boundary of HCC. Using biotinylation method, we developed a CSF-1R-conjugated nanobubble CSF-1R (NBCSF–1R) using a thin-film hydration method for margin detection of HCC. CSF-1R expression was higher in macrophages than in HCC cell lines. Furthermore, immunofluorescence showed that CSF-1R were largely located in the margin of xenograft tumor and IFRA models. In vitro, NBCSF–1R was stable and provided a clear ultrasound image even after being stored for 6 months. In co-culture, NBCSF–1R adhered to macrophages significantly better than HCC cells (p = 0.05). In in vivo contrast-enhanced ultrasound imaging, the washout half-time of the NBCSF–1R was significantly greater than that of NBCTRL and Sonovue® (p = 0.05). The signal intensity of the tumor periphery was higher than the tumor center or non-tumor region after NBCSF–1R injection. Taken together, NBCSF–1R may potentially be used as a non-invasive diagnostic modality in the margin detection of HCC, thereby improving the efficiency of RFA. This platform may also serve as a complement method to detect residual HCC after RFA; and may also be used for targeted delivery of therapeutic drugs or genes.
Collapse
Affiliation(s)
- Qiongchao Jiang
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yunting Zeng
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yanni Xu
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaoyun Xiao
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hejun Liu
- Department of Hyperbaric Oxygen, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Boyang Zhou
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yao Kong
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Phei Er Saw
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Baoming Luo
- Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
11
|
Ramos JRC, Rath AG, Genzel Y, Sandig V, Reichl U. A dynamic model linking cell growth to intracellular metabolism and extracellular by-product accumulation. Biotechnol Bioeng 2020; 117:1533-1553. [PMID: 32022250 DOI: 10.1002/bit.27288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 12/12/2019] [Accepted: 01/26/2020] [Indexed: 12/16/2022]
Abstract
Mathematical modeling of animal cell growth and metabolism is essential for the understanding and improvement of the production of biopharmaceuticals. Models can explain the dynamic behavior of cell growth and product formation, support the identification of the most relevant parameters for process design, and significantly reduce the number of experiments to be performed for process optimization. Few dynamic models have been established that describe both extracellular and intracellular dynamics of growth and metabolism of animal cells. In this study, a model was developed, which comprises a set of 33 ordinary differential equations to describe batch cultivations of suspension AGE1.HN.AAT cells considered for the production of α1-antitrypsin. This model combines a segregated cell growth model with a structured model of intracellular metabolism. Overall, it considers the viable cell concentration, mean cell diameter, viable cell volume, concentration of extracellular substrates, and intracellular concentrations of key metabolites from the central carbon metabolism. Furthermore, the release of metabolic by-products such as lactate and ammonium was estimated directly from the intracellular reactions. Based on the same set of parameters, this model simulates well the dynamics of four independent batch cultivations. Analysis of the simulated intracellular rates revealed at least two distinct cellular physiological states. The first physiological state was characterized by a high glycolytic rate and high lactate production. Whereas the second state was characterized by efficient adenosine triphosphate production, a low glycolytic rate, and reactions of the TCA cycle running in the reverse direction from α-ketoglutarate to citrate. Finally, we show possible applications of the model for cell line engineering and media optimization with two case studies.
Collapse
Affiliation(s)
- João R C Ramos
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Alexander G Rath
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
- Bioprocess Engineering, AMINO GmbH, Frellstedt, Germany
| | - Yvonne Genzel
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Volker Sandig
- Bioprocess Engineering, ProBioGen AG, Berlin, Germany
| | - Udo Reichl
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
- Bioprocess Engineering, Otto von Guericke University Magdeburg, Chair of Bioprocess Engineering, Magdeburg, Germany
| |
Collapse
|
12
|
Nittayacharn P, Yuan HX, Hernandez C, Bielecki P, Zhou H, Exner AA. Enhancing Tumor Drug Distribution With Ultrasound-Triggered Nanobubbles. J Pharm Sci 2019; 108:3091-3098. [PMID: 31095958 PMCID: PMC6708467 DOI: 10.1016/j.xphs.2019.05.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/30/2019] [Accepted: 05/07/2019] [Indexed: 01/09/2023]
Abstract
Issues with limited intratumoral drug penetration and heterogeneous drug distribution continue to impede the therapeutic efficacy of nanomedicine-based delivery systems. Ultrasound (US)-enhanced drug delivery has emerged as one effective means of overcoming these challenges. Acoustic cavitation in the presence of nanoparticles has shown to increase the cellular uptake and distribution of chemotherapeutic agents in vivo. In this study, we investigated the potential of a drug-loaded echogenic nanoscale bubbles in combination with low frequency (3 MHz), high energy (2 W/cm2) US for antitumor therapy. The doxorubicin-loaded nanobubbles (Dox-NBs) stabilized with an interpenetrating polymer mesh were 171.5 ± 20.9 nm in diameter. When used in combination with therapeutic US, Dox-NBs combined with free drug showed significantly higher (*p < 0.05) intracellular uptake and therapeutic efficacy compared with free drug. When injected intravenously in vivo, Dox-NBs + therapeutic US showed significantly higher (*p < 0.05) accumulation and better distribution of Dox in tumors when compared with free drug. This strategy provides an effective and simple method to increase the local dose and distribution of otherwise systemically toxic chemotherapeutic agents for cancer therapies.
Collapse
Affiliation(s)
- Pinunta Nittayacharn
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Hai-Xia Yuan
- Department of Ultrasound, Zhongshan Hospital of Fudan University, 180 Fenglin Road, Shanghai 200032, China; Department of Radiology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Christopher Hernandez
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Peter Bielecki
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Haoyan Zhou
- GSK 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426-0989
| | - Agata A Exner
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106; Department of Radiology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106.
| |
Collapse
|
13
|
Mercado-Shekhar KP, Su H, Kalaikadal DS, Lorenz JN, Manglik RM, Holland CK, Redington AN, Haworth KJ. Acoustic droplet vaporization-mediated dissolved oxygen scavenging in blood-mimicking fluids, plasma, and blood. ULTRASONICS SONOCHEMISTRY 2019; 56:114-124. [PMID: 31101245 PMCID: PMC6659737 DOI: 10.1016/j.ultsonch.2019.03.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/20/2018] [Accepted: 03/27/2019] [Indexed: 05/20/2023]
Abstract
Acoustic droplet vaporization (ADV) has been shown to reduce the partial pressure of oxygen (PO2) in a fluid. The goals of this study were three-fold: 1) to determine the ADV pressure amplitude threshold in fluids that had physiologically relevant values for surface tension, protein concentration, and viscosity; 2) to assess whether these parameters and fluid mixing affect ADV-mediated PO2 reduction; and 3) to assess the feasibility of ADV-mediated PO2 reduction in plasma and whole blood. In vitro ADV experiments were conducted using perfluoropentane droplets (number density: 5 × 106 ± 0.2 × 106/mL) dispersed in fluids (saline, polyvinylpyrrolidone solutions, porcine plasma, or porcine whole blood) that had a physiological range of surface tensions (62-68 mN/m), protein concentrations (0 and 68.7 mg/mL), and viscosities (0.7-4 cP). Droplets were exposed to pulsed ultrasound (5 MHz, 4.25 MPa peak negative pressure) while passing through a 37 °C flow system with inline PO2 sensors. In select experiments, the fluid also passed through mixing channels after ultrasound exposure. Our results revealed that the ADV pressure thresholds were the same for all fluids. Surface tension and protein concentration had no effect on PO2 reduction. Increasing viscosity attenuated PO2 reduction. However, the attenuated effect was absent after fluid mixing. Furthermore, ADV-mediated PO2 reduction in whole blood (30.8 ± 3.2 mmHg) was less than that in a polyvinylpyrrolidone solution (40.2 ± 2.1 mmHg) with equal viscosity. These findings should be considered when planning clinical studies of ADV-mediated PO2 reduction and other biomedical applications of ADV.
Collapse
Affiliation(s)
| | - Haili Su
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Deepak S Kalaikadal
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - John N Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, USA
| | - Raj M Manglik
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Christy K Holland
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Andrew N Redington
- Division of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Kevin J Haworth
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA; Division of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| |
Collapse
|
14
|
Zhang S, Xu T, Cui Z, Shi W, Wu S, Zong Y, Niu G, He X, Wan M. Time and Frequency Characteristics of Cavitation Activity Enhanced by Flowing Phase-Shift Nanodroplets and Lipid-Shelled Microbubbles During Focused Ultrasound Exposures. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:2118-2132. [PMID: 31151732 DOI: 10.1016/j.ultrasmedbio.2019.04.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/02/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
This study investigated and compared the time and frequency characteristics of cavitation activity between phase-shift nanodroplets (NDs) and lipid-shelled microbubbles (MBs) exposed to focused ultrasound (FUS) under physiologically relevant flow conditions. Root-mean-square (RMS) of broadband noise, spectrograms of the passive cavitation detection signals and inertial cavitation doses (ICDs) were calculated during FUS at varying mean flow velocities and two different peak-rarefactional pressures. At a lower pressure of 0.94 MPa, the mean values of the RMS amplitudes versus time for the NDs showed an upward trend but slowed down as the mean flow velocity increased. For flowing NDs, the rate of growth in RMS amplitudes within 2-5 MHz decreased more obviously than those within 5-8 MHz. At a higher pressure of 1.07 MPa, the increase in RMS amplitudes was accelerated as the mean flow velocity increased from 0 to 10 cm/s and slowed down as the mean flow velocity reached 15 cm/s. The general downward trends of RMS amplitudes for the MBs were retarded as the mean flow velocity increased at both acoustic pressures of 0.94 MPa and 1.07 MPa. At 0.94 MPa, the mean ICD value for the NDs decreased from 57 to 36 as the mean flow velocity increased from 0 to 20 cm/s. At 1.07 MPa, the mean ICD value initially increased from 45 to 57 as the mean flow velocity increased from 0 to 10 cm/s and subsequently decreased to 43 as the mean flow velocity reached 20 cm/s. For the MBs, the mean ICD value increased with increasing mean flow velocity at both acoustic pressures. These results could aid in future investigations of cavitation-enhanced FUS with the flowing phase-shift NDs and encapsulated, gas-filled MBs for various applications.
Collapse
Affiliation(s)
- Siyuan Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Tianqi Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Zhiwei Cui
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Wen Shi
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Shan Wu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Gang Niu
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Xijing He
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, People's Republic of China
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
| |
Collapse
|
15
|
Harmon JN, Kabinejadian F, Seda R, Fabiilli ML, Kuruvilla S, Kuo CC, Greve JM, Fowlkes JB, Bull JL. Minimally invasive gas embolization using acoustic droplet vaporization in a rodent model of hepatocellular carcinoma. Sci Rep 2019; 9:11040. [PMID: 31363130 PMCID: PMC6667465 DOI: 10.1038/s41598-019-47309-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022] Open
Abstract
Hepatocellular carcinoma is the third leading cause of cancer-related deaths worldwide. Many patients are not eligible for curative therapies, such as surgical resection of the tumor or a liver transplant. Transarterial embolization is one therapy clinically used in these cases; however, this requires a long procedure and careful placement of an intraarterial catheter. Gas embolization has been proposed as a fast, easily administered, more spatially selective, and less invasive alternative. Here, we demonstrate the feasibility and efficacy of using acoustic droplet vaporization to noninvasively generate gas emboli within vasculature. Intravital microscopy experiments were performed using the rat cremaster muscle to visually observe the formation of occlusions. Large gas emboli were produced within the vasculature in the rat cremaster, effectively occluding blood flow. Following these experiments, the therapeutic efficacy of gas embolization was investigated in an ectopic xenograft model of hepatocellular carcinoma in mice. The treatment group exhibited a significantly lower final tumor volume (ANOVA, p = 0.008) and growth rate than control groups - tumor growth was completely halted. Additionally, treated tumors exhibited significant necrosis as determined by histological analysis. To our knowledge, this study is the first to demonstrate the therapeutic efficacy of gas embolotherapy in a tumor model.
Collapse
Affiliation(s)
- Jennifer N Harmon
- Department of Biomedical Engineering, Tulane University, New Orleans, Louisiana, USA
| | - Foad Kabinejadian
- Department of Biomedical Engineering, Tulane University, New Orleans, Louisiana, USA
| | - Robinson Seda
- Data Office for Clinical and Translational Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Sibu Kuruvilla
- Department of Oncology, Stanford University, Stanford, California, USA
| | - Cathleen C Kuo
- Department of Neuroscience, Tulane University, New Orleans, Louisiana, USA
| | - Joan M Greve
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Joseph L Bull
- Department of Biomedical Engineering, Tulane University, New Orleans, Louisiana, USA.
| |
Collapse
|
16
|
Loskutova K, Grishenkov D, Ghorbani M. Review on Acoustic Droplet Vaporization in Ultrasound Diagnostics and Therapeutics. BIOMED RESEARCH INTERNATIONAL 2019; 2019:9480193. [PMID: 31392217 PMCID: PMC6662494 DOI: 10.1155/2019/9480193] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/10/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023]
Abstract
Acoustic droplet vaporization (ADV) is the physical process in which liquid undergoes phase transition to gas after exposure to a pressure amplitude above a certain threshold. In recent years, new techniques in ultrasound diagnostics and therapeutics have been developed which utilize microformulations with various physical and chemical properties. The purpose of this review is to give the reader a general idea on how ADV can be implemented for the existing biomedical applications of droplet vaporization. In this regard, the recent developments in ultrasound therapy which shed light on the ADV are considered. Modern designs of capsules and nanodroplets (NDs) are shown, and the material choices and their implications for function are discussed. The influence of the physical properties of the induced acoustic field, the surrounding medium, and thermophysical effects on the vaporization are presented. Lastly, current challenges and potential future applications towards the implementation of the therapeutic droplets are discussed.
Collapse
Affiliation(s)
- Ksenia Loskutova
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, SE-141 57 Huddinge, Sweden
| | - Dmitry Grishenkov
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, SE-141 57 Huddinge, Sweden
| | - Morteza Ghorbani
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, SE-141 57 Huddinge, Sweden
- Mechatronics Engineering Program, Faculty of Engineering and Natural Science, Sabanci University, Istanbul 34956, Turkey
| |
Collapse
|
17
|
Zhang G, Lin S, Leow CH, Pang KT, Hernández-Gil J, Long NJ, Eckersley R, Matsunaga T, Tang MX. Quantification of Vaporised Targeted Nanodroplets Using High-Frame-Rate Ultrasound and Optics. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1131-1142. [PMID: 30827708 DOI: 10.1016/j.ultrasmedbio.2019.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/08/2019] [Accepted: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Molecular targeted nanodroplets that can extravasate beyond the vascular space have great potential to improve tumor detection and characterisation. High-frame-rate ultrasound, on the other hand, is an emerging tool for imaging at a frame rate one to two orders of magnitude higher than those of existing ultrasound systems. In this study, we used high-frame-rate ultrasound combined with optics to study the acoustic response and size distribution of folate receptor (FR)-targeted versus non-targeted (NT)-nanodroplets in vitro with MDA-MB-231 breast cancer cells immediately after ultrasound activation. A flow velocity mapping technique, Stokes' theory and optical microscopy were used to estimate the size of both floating and attached vaporised nanodroplets immediately after activation. The floating vaporised nanodroplets were on average more than seven times larger than vaporised nanodroplets attached to the cells. The results also indicated that the acoustic signal of vaporised FR-targeted-nanodroplets persisted after activation, with 70% of the acoustic signals still present 1 s after activation, compared with the vaporised NT-nanodroplets, for which only 40% of the acoustic signal remained. The optical microscopic images revealed on average six times more vaporised FR-targeted-nanodroplets generated with a wider range of diameters (from 4 to 68 µm) that were still attached to the cells, compared with vaporised NT-nanodroplets (from 1 to 7 µm) with non-specific binding after activation. The mean size of attached vaporised FR-targeted-nanodroplets was on average about threefold larger than that of attached vaporised NT-nanodroplets. Taking advantage of high-frame-rate contrast-enhanced ultrasound and optical microscopy, this study offers an improved understanding of the vaporisation of the targeted nanodroplets in terms of their size and acoustic response in comparison with NT-nanodroplets. Such understanding would help in the design of optimised methodology for imaging and therapeutic applications.
Collapse
Affiliation(s)
- Ge Zhang
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Shengtao Lin
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Chee Hao Leow
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Kuin Tian Pang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | | | - Nicholas J Long
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Robert Eckersley
- Division of Imaging Sciences & Biomedical Engineering Department, King's College London, United Kingdom
| | - Terry Matsunaga
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, United Kingdom.
| |
Collapse
|
18
|
Rojas JD, Borden MA, Dayton PA. Effect of Hydrostatic Pressure, Boundary Constraints and Viscosity on the Vaporization Threshold of Low-Boiling-Point Phase-Change Contrast Agents. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:968-979. [PMID: 30658858 DOI: 10.1016/j.ultrasmedbio.2018.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/04/2018] [Accepted: 11/11/2018] [Indexed: 05/09/2023]
Abstract
The vaporization of low-boiling-point phase-change contrast agents (PCCAs) using ultrasound has been explored in vitro and in vivo. However, it has been reported that the pressure required for activation is higher in vivo, even after attenuation is accounted for. In this study, the effect of boundary constraints, hydrostatic pressure and viscosity on PCCA vaporization pressure threshold are evaluated to explore possible mechanisms for variations in in vivo vaporization behavior. Vaporization was measured in microtubes of varying inner diameter and a pressurized chamber under different hydrostatic pressures using a range of ultrasound pressures. Furthermore, the activation threshold was evaluated in the kidneys of rats. The results confirm that the vaporization threshold is higher in vivo and reveal an increasing activation threshold inversely proportional to constraining tube size and inversely proportional to surrounding viscosity in constrained environments. Counterintuitively, increased hydrostatic pressure had no significant effect experimentally on the PCCA vaporization threshold, although it was confirmed that this result was supported by homogeneous nucleation theory for liquid perfluorocarbon vaporization. These factors suggest that constraints caused by the surrounding tissue and capillary walls, as well as increased viscosity in vivo, contribute to the increased vaporization threshold compared with in vitro experiments, although more work is required to confirm all relevant factors.
Collapse
Affiliation(s)
- Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Mark A Borden
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
| |
Collapse
|
19
|
Rojas JD, Dayton PA. Vaporization Detection Imaging: A Technique for Imaging Low-Boiling-Point Phase-Change Contrast Agents with a High Depth of Penetration and Contrast-to-Tissue Ratio. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:192-207. [PMID: 30482709 DOI: 10.1016/j.ultrasmedbio.2018.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 08/17/2018] [Accepted: 08/22/2018] [Indexed: 06/09/2023]
Abstract
Phase-change contrast agents (PCCAs) possess advantages over microbubble contrast agents, such as the ability to extravasate and circulate longer in the vasculature that could enhance the diagnostic capabilities of contrast-enhanced ultrasound. PCCAs typically have a liquid perfluorocarbon (PFC) core that can be vaporized into echogenic microbubbles. Vaporization of submicron agents filled with liquid PFCs at body temperature usually requires therapeutic pressures higher than typically used for diagnostic imaging, but low-boiling-point PCCAs using decafluorobutane or octafluoropropane can be vaporized using pressures in the diagnostic imaging regime. Low-boiling-point PCCAs produce a unique acoustic signature that can be separated from tissue and bubble signals to make images with high contrast-to-tissue ratios. In this work, we explore the effect of pulse length and concentration on the vaporization signal of PCCAs and a new technique to capture and use the signals to make high contrast-to-tissue ratio images in vivo. The results indicate that using a short pulse may be ideal for imaging because it does not interact with created bubbles but still produces strong signals for making images. Furthermore, it was found that capturing PCCA vaporization signals produced higher contrast-to-tissue ratio values and better depth of penetration than imaging the bubbles generated by droplet activation using conventional contrast imaging techniques. The resolution of the vaporization signal images is poor because of the low frequency of the signals, but their high sensitivity may be used for applications such as molecular imaging, where the detection of small numbers of contrast agents is important.
Collapse
Affiliation(s)
- Juan D Rojas
- 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.
| |
Collapse
|
20
|
Rojas JD, Dayton PA. In Vivo Molecular Imaging Using Low-Boiling-Point Phase-Change Contrast Agents: A Proof of Concept Study. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:177-191. [PMID: 30318123 DOI: 10.1016/j.ultrasmedbio.2018.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/26/2018] [Accepted: 08/10/2018] [Indexed: 06/08/2023]
Abstract
Sub-micron phase-change contrast agents (PCCAs) have been proposed as a tool for ultrasound molecular imaging based on their potential to extravasate and target extravascular markers and also because of the potential to image these contrast agents with a high contrast-to-tissue ratio. We compare in vivo ultrasound molecular imaging with targeted low-boiling-point PCCAs and targeted microbubble contrast agents. Both agents were targeted to the intravascular (endothelial) integrin αvß3via a cyclic RGD peptide (cyclo-Arg-Gly-Asp-D-Tyr-Cys) mechanism and imaged in vivo in a rodent fibrosarcoma model, which exhibits angiogenic microvasculature. Signal intensity was measured using two different techniques, conventional contrast-specific imaging (amplitude/phase modulation) and a droplet vaporization imaging sequence, which detects the unique signature of vaporizing PCCAs. Data indicate that PCCA-specific imaging is more sensitive to small numbers of bound agents than conventional contrast imaging. However, data also revealed that contrast from targeted microbubbles was greater than that provided by PCCAs. Both control and targeted PCCAs were observed to be retained in tissue post-vaporization, which was expected for targeted agents but not expected for control agents. The exact mechanism underlying this observation remains unknown.
Collapse
Affiliation(s)
- Juan D Rojas
- 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.
| |
Collapse
|
21
|
Hadinger KP, Marshalek JP, Sheeran PS, Dayton PA, Matsunaga TO. Optimization of Phase-Change Contrast Agents for Targeting MDA-MB-231 Breast Cancer Cells. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:2728-2738. [PMID: 30228045 PMCID: PMC6215505 DOI: 10.1016/j.ultrasmedbio.2018.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 07/02/2018] [Accepted: 08/06/2018] [Indexed: 05/11/2023]
Abstract
Breast cancer remains a leading cause of death for women throughout the world. Recent advances in medical imaging technologies and tumor targeting agents signify vast potential for progress toward improved management of this global problem. Phase-change contrast agents (PCCAs) are dynamic imaging agents with practical applications in both the research and clinical settings. PCCAs possess characteristics that allow for cellular uptake where they can be converted from liquid-phase PCCAs to gaseous microbubbles via ultrasound energy. Previously, we reported successful internalization of folate-targeted PCCAs in MDA-MB-231 breast cancer cells followed by ultrasound-mediated activation to produce internalized microbubbles. This study examines the binding, internalization and activation of folate-receptor targeted PCCAs in MDA-MB-231 breast cancer cells as a function of gaseous core compositions, incubation time and ultrasound exposure period. In vitro results indicate that internalization and ultrasound-mediated activation of PCCAs were significantly greater using a 50:50 mixture of decafluorobutane:dodecafluoropentane compared with other core compositions: 50:50 octafluoropropane:decafluorobutane (p < 0.0001), decafluorobutane (p < 0.04) and dodecafluoropentane (p < 0.0001). Furthermore, it was found that PCCAs composed of perfluorocarbons with higher boiling points responded with greater activation efficiency when exposed to 12 s of ultrasound exposure as opposed to 4 s of ultrasound exposure. When evaluating different incubation times, it was found that incubating the PCCAs with breast cancer cells for 60 min did not produce significantly greater internalization and activation compared with incubation for 10 min; this was concluded after comparing the number of microbubbles present per cell before ultrasound versus post-ultrasound, and finding a ratio of intracellular microbubbles post-ultrasound/pre-ultrasound, 3.46 versus 3.14, respectively. The data collected in this study helps illustrate further optimization of folate-receptor targeted PCCAs for breast cancer targeting and imaging.
Collapse
Affiliation(s)
- Kyle P Hadinger
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Joseph P Marshalek
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Paul S Sheeran
- Physical Sciences Department, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Terry O Matsunaga
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
| |
Collapse
|
22
|
Zlitni A, Gambhir SS. Molecular imaging agents for ultrasound. Curr Opin Chem Biol 2018; 45:113-120. [PMID: 29631121 PMCID: PMC6609297 DOI: 10.1016/j.cbpa.2018.03.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 03/21/2018] [Accepted: 03/27/2018] [Indexed: 12/28/2022]
Abstract
Ultrasound (US) imaging is a safe, sensitive and affordable imaging modality with a wide usage in the clinic. US signal can be further enhanced by using echogenic contrast agents (UCAs) which amplify the US signal. Developments in UCAs which are targeted to sites of disease allow the use of US imaging to provide molecular information. Unfortunately, traditional UCAs are too large to leave the vascular space limiting the application of molecular US to intravascular markers. In this mini review, we highlight the most recent reports on the application of molecular US imaging in the clinic and summarize the latest nanoparticle platforms used to develop nUCAs. We believe that the highlighted technologies will have a great impact on the evolution of the US imaging field.
Collapse
Affiliation(s)
- Aimen Zlitni
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center at Stanford for Cancer Early Detection, Stanford University, Stanford, CA, United States
| | - Sanjiv S Gambhir
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center at Stanford for Cancer Early Detection, Stanford University, Stanford, CA, United States; Department of Bioengineering, Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States.
| |
Collapse
|
23
|
Liu C, Kapoor A, VanOsdol J, Ektate K, Kong Z, Ranjan A. A Spectral Fiedler Field-based Contrast Platform for Imaging of Nanoparticles in Colon Tumor. Sci Rep 2018; 8:11390. [PMID: 30061558 PMCID: PMC6065424 DOI: 10.1038/s41598-018-29675-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/14/2018] [Indexed: 12/24/2022] Open
Abstract
The temporal and spatial patterns of nanoparticle that ferry both imaging and therapeutic agent in solid tumors is significantly influenced by target tissue movement, low spatial resolution, and inability to accurately define regions of interest (ROI) at certain tissue depths. These combine to limit and define nanoparticle untreated regions in tumors. Utilizing graph and matrix theories, the objective of this project was to develop a novel spectral Fiedler field (SFF) based-computational technology for nanoparticle mapping in tumors. The novelty of SFF lies in the utilization of the changes in the tumor topology from baseline for contrast variation assessment. Data suggest that SFF can enhance the spatiotemporal contrast compared to conventional method by 2–3 folds in tumors. Additionally, the SFF contrast is readily translatable for assessment of tumor drug distribution. Thus, our SFF computational platform has the potential for integration into devices that allow contrast and drug delivery applications.
Collapse
Affiliation(s)
- Chenang Liu
- Grado Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, Virginia, USA
| | - Ankur Kapoor
- Siemens Healthineers, Princeton, New Jersey, USA
| | - Joshua VanOsdol
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Kalyani Ektate
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Zhenyu Kong
- Grado Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, Virginia, USA.
| | - Ashish Ranjan
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, USA.
| |
Collapse
|
24
|
Pellow C, Goertz DE, Zheng G. Breaking free from vascular confinement: status and prospects for submicron ultrasound contrast agents. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2017; 10:e1502. [PMID: 29148219 DOI: 10.1002/wnan.1502] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/23/2017] [Accepted: 09/30/2017] [Indexed: 12/11/2022]
Abstract
The development of encapsulated microbubbles (~1-6 μm) has expanded the utility of ultrasound from soft tissue anatomical imaging to not only functional intravascular imaging, but therapeutic interventions, with compelling studies of elicited biological effects. The large diameter of these bubbles has confined their utility to the vasculature, but converging interdisciplinary research pathways are giving rise to new submicron ultrasound contrast agents capable of extending their effects beyond the vascular compartment. This article reviews the status and prospects of exogenous agents including nanobubbles, echogenic liposomes, gas vesicles, cavitation seeds, and nanodroplets, and assesses outstanding criticisms preventing their advance. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Emerging Technologies.
Collapse
Affiliation(s)
- Carly Pellow
- Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Sunnybrook Research Institute, Toronto, Canada.,Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - David E Goertz
- Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Sunnybrook Research Institute, Toronto, Canada
| | - Gang Zheng
- Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| |
Collapse
|
25
|
Lin S, Zhang G, Leow CH, Tang MX. Effects of microchannel confinement on acoustic vaporisation of ultrasound phase change contrast agents. Phys Med Biol 2017; 62:6884-6898. [PMID: 28718774 DOI: 10.1088/1361-6560/aa8076] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The sub-micron phase change contrast agent (PCCA) composed of a perfluorocarbon liquid core can be activated into gaseous state and form stable echogenic microbubbles for contrast-enhanced ultrasound imaging. It has shown great promise in imaging microvasculature, tumour microenvironment, and cancer cells. Although PCCAs have been extensively studied for different diagnostic and therapeutic applications, the effect of biologically geometrical confinement on the acoustic vaporisation of PCCAs is still not clear. We have investigated the difference in PCCA-produced ultrasound contrast enhancement after acoustic activation with and without a microvessel confinement on a microchannel phantom. The experimental results indicated more than one-order of magnitude less acoustic vaporisation in a microchannel than that in a free environment taking into account the attenuation effect of the vessel on the microbubble scattering. This may provide an improved understanding in the applications of PCCAs in vivo.
Collapse
Affiliation(s)
- Shengtao Lin
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | | | | |
Collapse
|
26
|
Gao Y, Hernandez C, Yuan HX, Lilly J, Kota P, Zhou H, Wu H, Exner AA. Ultrasound molecular imaging of ovarian cancer with CA-125 targeted nanobubble contrast agents. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 13:2159-2168. [PMID: 28603079 DOI: 10.1016/j.nano.2017.06.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/09/2017] [Accepted: 06/01/2017] [Indexed: 02/03/2023]
Abstract
Ultrasound is frequently utilized in diagnosis of gynecologic malignancies such as ovarian cancer. Because epithelial ovarian cancer (EOC) is often characterized by overexpression of cancer antigen 125 (CA-125), ultrasound contrast agents able to target this molecular signature could be a promising complementary strategy. In this work, we demonstrate application of CA-125-targeted echogenic lipid and surfactant-stabilized nanobubbles imaged with standard clinical contrast harmonic ultrasound for imaging of CA-125 positive OVCAR-3 tumors in mice. Surface functionalization of the nanobubbles with a CA-125 antibody achieved rapid significantly (P < 0.05) enhanced tumor accumulation, higher peak ultrasound signal intensity and slower wash out rates in OVCAR-3 tumors compared to CA-125 negative SKOV-3 tumors. Targeted nanobubbles also exhibited increased tumor retention and prolonged echogenicity compared to untargeted nanobubbles. Data suggest that ultrasound molecular imaging using CA-125 antibody-conjugated nanobubbles may contribute to improved diagnosis of EOC.
Collapse
Affiliation(s)
- Yong Gao
- Department of Ultrasound, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China; Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Christopher Hernandez
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Hai-Xia Yuan
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Jacob Lilly
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Pavan Kota
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Haoyan Zhou
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Hanping Wu
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| | - Agata A Exner
- Department of Radiology, Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA.
| |
Collapse
|
27
|
Liu J, Shang T, Wang F, Cao Y, Hao L, Ren J, Ran H, Wang Z, Li P, Du Z. Low-intensity focused ultrasound (LIFU)-induced acoustic droplet vaporization in phase-transition perfluoropentane nanodroplets modified by folate for ultrasound molecular imaging. Int J Nanomedicine 2017; 12:911-923. [PMID: 28184161 PMCID: PMC5291457 DOI: 10.2147/ijn.s122667] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The commonly used ultrasound (US) molecular probes, such as targeted microbubbles and perfluorocarbon emulsions, present a number of inherent problems including the conflict between US visualization and particle penetration. This study describes the successful fabrication of phase changeable folate-targeted perfluoropentane nanodroplets (termed FA-NDs), a novel US molecular probe for tumor molecular imaging with US. Notably, these FA-NDs can be triggered by low-intensity focused US (LIFU) sonication, providing excellent US enhancement in B-mode and contrast-enhanced US mode in vitro. After intravenous administration into nude mice bearing SKOV3 ovarian carcinomas, 1,1′-dioctadecyl-3,3,3′,3′ -tetramethylindotricarbocya-nine iodide-labeled FA-NDs were found to accumulate in the tumor region. FA-NDs injection followed by LIFU sonication exhibited remarkable US contrast enhancement in the tumor region. In conclusion, combining our elaborately developed FA-NDs with LIFU sonication provides a potential protocol for US molecular imaging in folate receptor-overexpressing tumors.
Collapse
Affiliation(s)
- Jianxin Liu
- Chongqing Key Laboratory of Ultrasound Molecular Imaging
| | - Tingting Shang
- Chongqing Key Laboratory of Ultrasound Molecular Imaging
| | - Fengjuan Wang
- Chongqing Key Laboratory of Ultrasound Molecular Imaging
| | - Yang Cao
- Chongqing Key Laboratory of Ultrasound Molecular Imaging
| | - Lan Hao
- Chongqing Key Laboratory of Ultrasound Molecular Imaging
| | - JianLi Ren
- Chongqing Key Laboratory of Ultrasound Molecular Imaging; Department of Ultrasound
| | - Haitao Ran
- Chongqing Key Laboratory of Ultrasound Molecular Imaging; Department of Ultrasound
| | - Zhigang Wang
- Chongqing Key Laboratory of Ultrasound Molecular Imaging; Department of Ultrasound
| | - Pan Li
- Chongqing Key Laboratory of Ultrasound Molecular Imaging; Department of Ultrasound
| | - Zhiyu Du
- Postgraduate Department, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| |
Collapse
|
28
|
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.
Collapse
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.
| |
Collapse
|
29
|
Sheeran PS, Matsuura N, Borden MA, Williams R, Matsunaga TO, Burns PN, Dayton PA. Methods of Generating Submicrometer Phase-Shift Perfluorocarbon Droplets for Applications in Medical Ultrasonography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:252-263. [PMID: 27775902 PMCID: PMC5706463 DOI: 10.1109/tuffc.2016.2619685] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Continued advances in the field of ultrasound and ultrasound contrast agents have created new approaches to imaging and medical intervention. Phase-shift perfluorocarbon droplets, which can be vaporized by ultrasound energy to transition from the liquid to the vapor state, are one of the most highly researched alternatives to clinical ultrasound contrast agents (i.e., microbubbles). In this paper, part of a special issue on methods in biomedical ultrasonics, we survey current techniques to prepare ultrasound-activated nanoscale phase-shift perfluorocarbon droplets, including sonication, extrusion, homogenization, microfluidics, and microbubble condensation. We provide example protocols and discuss advantages and limitations of each approach. Finally, we discuss best practice in characterization of this class of contrast agents with respect to size distribution and ultrasound activation.
Collapse
|
30
|
Rojas JD, Dayton PA. Optimizing Acoustic Activation of Phase Change Contrast Agents With the Activation Pressure Matching Method: A Review. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:264-272. [PMID: 27740481 PMCID: PMC5270505 DOI: 10.1109/tuffc.2016.2616304] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Submicrometer phase-change contrast agents (PCCAs) consist of a liquid perfluorocarbon (PFC) core that can be vaporized by ultrasound (acoustic droplet vaporization) to generate contrast with excellent spatial and temporal control. When these agents, commonly referred to as nanodroplets, are formulated with cores of low boiling-point PFCs such as decafluorobutane and octafluoropropane, they can be activated with low-mechanical-index (MI) imaging pulses for diagnostic applications. Since the utilization of minimum MI is often desirable to avoid unnecessary biological effects, enabling consistent activation of these agents in an acoustic field is a challenge because the energy that must be delivered to achieve the vaporization threshold increases with depth due to attenuation. A novel vaporization approach called activation pressure matching (APM) has been developed to deliver the same pressure throughout a field of view in order to produce uniform nanodroplet vaporization and to limit the amount of energy that is delivered. In this paper, we discuss the application of this method with a Verasonics V1 Research Ultrasound System to modulate the output pressure from an ATL L11-5 transducer. Vaporization-pulse spacing optimization can be used in addition to matching the activation pressure through depth, and we demonstrate the feasibility of this approach both in vivo and in vitro. The use of optimized vaporization parameters increases the amount of time a single bolus of nanodroplets can generate useful contrast and provides consistent image enhancement in vivo. Therefore, APM is a useful technique for maximizing the efficacy of PCCA while minimizing delivered acoustic energy.
Collapse
|
31
|
Marshalek JP, Sheeran PS, Ingram P, Dayton PA, Witte RS, Matsunaga TO. Intracellular delivery and ultrasonic activation of folate receptor-targeted phase-change contrast agents in breast cancer cells in vitro. J Control Release 2016; 243:69-77. [PMID: 27686582 DOI: 10.1016/j.jconrel.2016.09.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/01/2016] [Accepted: 09/12/2016] [Indexed: 12/22/2022]
Abstract
Breast cancer is a diverse and complex disease that remains one of the leading causes of death among women. Novel, outside-of-the-box imaging and treatment methods are needed to supplement currently available technologies. In this study, we present evidence for the intracellular delivery and ultrasound-stimulated activation of folate receptor (FR)-targeted phase-change contrast agents (PCCAs) in MDA-MB-231 and MCF-7 breast cancer cells in vitro. PCCAs are lipid-coated, perfluorocarbon-filled particles formulated as nanoscale liquid droplets capable of vaporization into gaseous microbubbles for imaging or therapy. Cells were incubated with 1:1 decafluorobutane (DFB)/octafluoropropane (OFP) PCCAs for 1h, imaged via confocal microscopy, exposed to ultrasound (9MHz, MI=1.0 or 1.5), and imaged again after insonation. FR-targeted PCCAs were observed intracellularly in both cell lines, but uptake was significantly greater (p<0.001) in MDA-MB-231 cells (93.0% internalization at MI=1.0, 79.5% at MI=1.5) than MCF-7 cells (42.4% internalization at MI=1.0, 35.7% at MI=1.5). Folate incorporation increased the frequency of intracellular PCCA detection 45-fold for MDA-MB-231 cells and 7-fold for MCF-7 cells, relative to untargeted PCCAs. Intracellularly activated PCCAs ranged from 500nm to 6μm (IQR=800nm-1.5μm) with a mean diameter of 1.15±0.59 (SD) microns. The work presented herein demonstrates the feasibility of PCCA intracellular delivery and activation using breast cancer cells, illuminating a new platform toward intracellular imaging or therapeutic delivery with ultrasound.
Collapse
Affiliation(s)
| | - Paul S Sheeran
- Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Pier Ingram
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC, USA
| | - Russell S Witte
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| | - Terry O Matsunaga
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA.
| |
Collapse
|
32
|
Maadi M, Zemp RJ. Self and Mutual Radiation Impedances for Modeling of Multi-Frequency CMUT Arrays. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:1441-1454. [PMID: 27392351 DOI: 10.1109/tuffc.2016.2587868] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Multi-frequency capacitive micromachined ultrasonic transducers (CMUTs) consist of interlaced large and small membranes for multiband operation. In modeling these devices, accurate and computationally efficient methods are required for computing self- and mutual-acoustic-radiation impedances. However, most previous works considered mutual-acoustic impedance between radiators of identical size. A need was thus found to revisit the fundamental framework for mutual-acoustic impedance for its applicability to radiators, especially flexural disks, of differing size. The Bouwkamp integral method is used to achieve infinite series expressions for self- and mutual-acoustic radiation impedances. Polynomial-fitting-based approximate relations of the mutual-acoustic impedance are developed for arbitrary array geometries and are in good agreement with exact expressions. The derived mutual-acoustic impedance is incorporated into equivalent circuit models of multi-frequency CMUTs showing excellent agreement with finite element modeling. The results demonstrate that mutual-acoustic interactions significantly impact device performance. The framework presented here may prove valuable for future design of multi-frequency arrays for novel multiscale imaging, superharmonic contrast imaging, and image therapy applications.
Collapse
|
33
|
Peyman SA, McLaughlan JR, Abou-Saleh RH, Marston G, Johnson BRG, Freear S, Coletta PL, Markham AF, Evans SD. On-chip preparation of nanoscale contrast agents towards high-resolution ultrasound imaging. LAB ON A CHIP 2016; 16:679-87. [PMID: 26689151 DOI: 10.1039/c5lc01394a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Micron-sized lipid-stabilised bubbles of heavy gas have been utilised as contrast agents for diagnostic ultrasound (US) imaging for many years. Typically bubbles between 1 and 8 μm in diameter are produced to enhance imaging in US by scattering sound waves more efficiently than surrounding tissue. A potential area of interest for Contrast Enhanced Ultrasound (CEUS) are bubbles with diameters <1 μm or 'nanobubbles.' As bubble diameter decreases, ultrasonic resonant frequency increases, which could lead to an improvement in resolution for high-frequency imaging applications when using nanobubbles. In addition, current US contrast agents are limited by their size to the vasculature in vivo. However, molecular-targeted nanobubbles could penetrate into the extra-vascular space of cancerous tissue providing contrast in regions inaccessible to traditional microbubbles. This paper reports a new microfluidic method for the generation of sub-micron sized lipid stabilised particles containing perfluorocarbon (PFC). The nanoparticles are produced in a unique atomisation-like flow regime at high production rates, in excess of 10(6) particles per s and at high concentration, typically >10(11) particles per mL. The average particle diameter appears to be around 100-200 nm. These particles, suspected of being a mix of liquid and gaseous C4F10 due to Laplace pressure, then phase convert into nanometer sized bubbles on the application of US. In vitro ultrasound characterisation from these nanoparticle populations showed strong backscattering compared to aqueous filled liposomes of a similar size. The nanoparticles were stable upon injection and gave excellent contrast enhancement when used for in vivo imaging, compared to microbubbles with an equivalent shell composition.
Collapse
Affiliation(s)
- Sally A Peyman
- School of Physics and Astronomy, University of Leeds, LS2 9JT, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Arena CB, Novell A, Sheeran PS, Puett C, Moyer LC, Dayton PA. Dual-frequency acoustic droplet vaporization detection for medical imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2015; 62:1623-33. [PMID: 26415125 PMCID: PMC5507352 DOI: 10.1109/tuffc.2014.006883] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Liquid-filled perfluorocarbon droplets emit a unique acoustic signature when vaporized into gas-filled microbubbles using ultrasound. Here, we conducted a pilot study in a tissue-mimicking flow phantom to explore the spatial aspects of droplet vaporization and investigate the effects of applied pressure and droplet concentration on image contrast and axial and lateral resolution. Control microbubble contrast agents were used for comparison. A confocal dual-frequency transducer was used to transmit at 8 MHz and passively receive at 1 MHz. Droplet signals were of significantly higher energy than microbubble signals. This resulted in improved signal separation and high contrast-to-tissue ratios (CTR). Specifically, with a peak negative pressure (PNP) of 450 kPa applied at the focus, the CTR of B-mode images was 18.3 dB for droplets and -0.4 for microbubbles. The lateral resolution was dictated by the size of the droplet activation area, with lower pressures resulting in smaller activation areas and improved lateral resolution (0.67 mm at 450 kPa). The axial resolution in droplet images was dictated by the size of the initial droplet and was independent of the properties of the transmit pulse (3.86 mm at 450 kPa). In post-processing, time-domain averaging (TDA) improved droplet and microbubble signal separation at high pressures (640 kPa and 700 kPa). Taken together, these results indicate that it is possible to generate high-sensitivity, high-contrast images of vaporization events. In the future, this has the potential to be applied in combination with droplet-mediated therapy to track treatment outcomes or as a standalone diagnostic system to monitor the physical properties of the surrounding environment.
Collapse
|
35
|
Burgess MT, Porter TM. Acoustic Cavitation-Mediated Delivery of Small Interfering Ribonucleic Acids with Phase-Shift Nano-Emulsions. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:2191-201. [PMID: 25979417 PMCID: PMC4466208 DOI: 10.1016/j.ultrasmedbio.2015.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 03/30/2015] [Accepted: 04/01/2015] [Indexed: 05/11/2023]
Abstract
Localized, targeted delivery of small interfering ribonucleic acid (siRNA) has been the foremost hurdle in the use of siRNA for the treatment of various diseases. Major advances have been achieved in the synthesis of siRNA, which have led to greater target messenger RNA (mRNA) silencing and stability under physiologic conditions. Although numerous delivery strategies have shown promise, there are still limited options for targeted delivery and release of siRNA administered systemically. In this in vitro study, phase-shift nano-emulsions (PSNE) were explored as cavitation nuclei to facilitate free siRNA delivery to cancer cells via sonoporation. A cell suspension containing varying amounts of PSNE and siRNA was exposed to 5-MHz pulsed ultrasound at fixed settings (6.2-MPa peak negative pressure, 5-cycle pulses, 250-Hz pulse repetition frequency (PRF) and total exposure duration of 100 s). Inertial cavitation emissions were detected throughout the exposure using a passive cavitation detector. Successful siRNA delivery was achieved (i.e., >50% cell uptake) with high (>80%) viability. The percentage of cells with siRNA uptake was correlated with the amount of inertial cavitation activity generated from vaporized PSNE. The siRNA remained functional after delivery, significantly reducing expression of green fluorescent protein in a stably transfected cell line. These results indicate that vaporized PSNE can facilitate siRNA entry into the cytosol of a majority of sonicated cells and may provide a non-endosomal route for siRNA delivery.
Collapse
Affiliation(s)
- Mark T Burgess
- Department of Mechanical Engineering and Center for Nanoscience and Nanobiotechnology, Boston University, Boston, Massachusetts, USA.
| | - Tyrone M Porter
- Department of Mechanical Engineering and Center for Nanoscience and Nanobiotechnology, Boston University, Boston, Massachusetts, USA; Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
| |
Collapse
|
36
|
Li S, Lin S, Cheng Y, Matsunaga TO, Eckersley RJ, Tang MX. Quantifying activation of perfluorocarbon-based phase-change contrast agents using simultaneous acoustic and optical observation. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:1422-31. [PMID: 25656747 PMCID: PMC5706456 DOI: 10.1016/j.ultrasmedbio.2014.12.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 12/01/2014] [Accepted: 12/15/2014] [Indexed: 05/05/2023]
Abstract
Phase-change contrast agents in the form of nanoscale droplets can be activated into microbubbles by ultrasound, extending the contrast beyond the vasculature. This article describes simultaneous optical and acoustical measurements for quantifying the ultrasound activation of phase-change contrast agents over a range of concentrations. In experiments, decafluorobutane-based nanodroplets of different dilutions were sonicated with a high-pressure activation pulse and two low-pressure interrogation pulses immediately before and after the activation pulse. The differences between the pre- and post-interrogation signals were calculated to quantify the acoustic power scattered by the microbubbles activated over a range of droplet concentrations. Optical observation occurred simultaneously with the acoustic measurement, and the pre- and post-microscopy images were processed to generate an independent quantitative indicator of the activated microbubble concentration. Both optical and acoustic measurements revealed linear relationships to the droplet concentration at a low concentration range <10(8)/mL when measured at body temperature. Further increases in droplet concentration resulted in saturation of the acoustic interrogation signal. Compared with body temperature, room temperature was found to produce much fewer and larger bubbles after ultrasound droplet activation.
Collapse
Affiliation(s)
- Sinan Li
- Department of Bioengineering, Imperial College London, London, UK
| | - Shengtao Lin
- Department of Bioengineering, Imperial College London, London, UK
| | - Yi Cheng
- Department of Bioengineering, Imperial College London, London, UK
| | - Terry O Matsunaga
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | | | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, UK.
| |
Collapse
|
37
|
Sheeran PS, Rojas JD, Puett C, Hjelmquist J, Arena CB, Dayton PA. Contrast-enhanced ultrasound imaging and in vivo circulatory kinetics with low-boiling-point nanoscale phase-change perfluorocarbon agents. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:814-31. [PMID: 25619781 PMCID: PMC5599113 DOI: 10.1016/j.ultrasmedbio.2014.10.020] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 05/03/2023]
Abstract
Many studies have explored phase-change contrast agents (PCCAs) that can be vaporized by an ultrasonic pulse to form microbubbles for ultrasound imaging and therapy. However, few investigations have been published on the utility and characteristics of PCCAs as contrast agents in vivo. In this study, we examine the properties of low-boiling-point nanoscale PCCAs evaluated in vivo and compare data with those for conventional microbubbles with respect to contrast generation and circulation properties. To do this, we develop a custom pulse sequence to vaporize and image PCCAs using the Verasonics research platform and a clinical array transducer. Results indicate that droplets can produce contrast enhancement similar to that of microbubbles (7.29 to 18.24 dB over baseline, depending on formulation) and can be designed to circulate for as much as 3.3 times longer than microbubbles. This study also reports for the first time the ability to capture contrast washout kinetics of the target organ as a measure of vascular perfusion.
Collapse
Affiliation(s)
- Paul S Sheeran
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Connor Puett
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Jordan Hjelmquist
- Department of Biomedical Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Christopher B Arena
- 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.
| |
Collapse
|
38
|
Jafari S, Diou O, Mamou J, Renault G, Fattal E, Tsapis N, Bridal SL. High-frequency (20 to 40 MHz) acoustic response of liquid-filled nanocapsules. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2014; 61:5-15. [PMID: 24402891 DOI: 10.1109/tuffc.2014.6689771] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Liquid-core nanoparticles are promising candidates for targeted ultrasound-controlled therapy, but their acoustic detection remains challenging. High-frequency (20 to 40 MHz) tone burst sequences were implemented with a programmable ultrasound biomicroscope to characterize acoustic response from perfluorooctyl bromide-core nanoparticles with thick poly(lactide-coglycolide) (PLGA) shells. Radio-frequency signals were acquired from flowing solutions of nanoparticles with two different shell-thickness-to-particle-radius ratios, solid PLGA nanoparticles, and latex nanobeads (linear controls). Normalized fundamental (20 MHz) and second-harmonic power spectral density (PSD) increased with particle concentration and was highest for the thinnest shelled particles. The second- harmonic PSD was detectable from the nanoparticles for peak rarefactional pressures (PRP) from 0.97 to 2.01 MPa at 23 cycles and for tone bursts from 11 to 23 cycles at 2.01 MPa. Their second-harmonic¿to¿fundamental ratio increased as a function of PRP and number of cycles. Within the same PRP and cycle ranges, the second-harmonic¿to¿fundamental ratios from matched concentration solutions of latex nanobeads and solid PLGA nanoparticles was more weakly detectable but also increased with PRP and number of cycles. Nanoparticles were detectable under flow conditions in vitro using the contrast agent mode of a high-frequency commercial scanner. These results characterize linear acoustic response from the nanoparticles (20 to 40 MHz) and demonstrate potential for their highfrequency detection.
Collapse
|
39
|
Sheeran PS, Dayton PA. Improving the performance of phase-change perfluorocarbon droplets for medical ultrasonography: current progress, challenges, and prospects. SCIENTIFICA 2014; 2014:579684. [PMID: 24991447 PMCID: PMC4058811 DOI: 10.1155/2014/579684] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/02/2014] [Indexed: 05/12/2023]
Abstract
Over the past two decades, perfluorocarbon (PFC) droplets have been investigated for biomedical applications across a wide range of imaging modalities. More recently, interest has increased in "phase-change" PFC droplets (or "phase-change" contrast agents), which can convert from liquid to gas with an external energy input. In the field of ultrasound, phase-change droplets present an attractive alternative to traditional microbubble agents for many diagnostic and therapeutic applications. Despite the progress, phase-change PFC droplets remain far from clinical implementation due to a number of challenges. In this review, we survey our recent work to enhance the performance of phase-change agents for ultrasound through a variety of techniques in order to provide increased efficacy in therapeutic applications of ultrasound and enable previously unexplored applications in diagnostic and molecular imaging.
Collapse
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
| | - Paul A. Dayton
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC 27599, USA
- *Paul A. Dayton:
| |
Collapse
|
40
|
Chen CC, Sheeran PS, Wu SY, Olumolade OO, Dayton PA, Konofagou EE. Targeted drug delivery with focused ultrasound-induced blood-brain barrier opening using acoustically-activated nanodroplets. J Control Release 2013; 172:795-804. [PMID: 24096019 DOI: 10.1016/j.jconrel.2013.09.025] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 09/16/2013] [Accepted: 09/18/2013] [Indexed: 01/19/2023]
Abstract
Focused ultrasound (FUS) in the presence of systemically administered microbubbles has been shown to locally, transiently and reversibly increase the permeability of the blood-brain barrier (BBB), thus allowing targeted delivery of therapeutic agents in the brain for the treatment of central nervous system diseases. Currently, microbubbles are the only agents that have been used to facilitate the FUS-induced BBB opening. However, they are constrained within the intravascular space due to their micron-size diameters, limiting the delivery effect at or near the microvessels. In the present study, acoustically-activated nanodroplets were used as a new class of contrast agents to mediate FUS-induced BBB opening in order to study the feasibility of utilizing these nanoscale phase-shift particles for targeted drug delivery in the brain. Significant dextran delivery was achieved in the mouse hippocampus using nanodroplets at clinically relevant pressures. Passive cavitation detection was used in the attempt to establish a correlation between the amount of dextran delivered in the brain and the acoustic emission recorded during sonication. Conventional microbubbles with the same lipid shell composition and perfluorobutane core as the nanodroplets were also used to compare the efficiency of an FUS-induced dextran delivery. It was found that nanodroplets had a higher BBB opening pressure threshold but a lower stable cavitation threshold than microbubbles, suggesting that contrast agent-dependent acoustic emission monitoring was needed. A more homogeneous dextran delivery within the targeted hippocampus was achieved using nanodroplets without inducing inertial cavitation or compromising safety. Our results offered a new means of developing the FUS-induced BBB opening technology for potential extravascular targeted drug delivery in the brain, extending the potential drug delivery region beyond the cerebral vasculature.
Collapse
Affiliation(s)
- Cherry C Chen
- Department of Biomedical Engineering, Columbia University, New York 10027, NY, USA
| | | | | | | | | | | |
Collapse
|
41
|
Sheeran PS, Matsunaga TO, Dayton PA. Phase-transition thresholds and vaporization phenomena for ultrasound phase-change nanoemulsions assessed via high-speed optical microscopy. Phys Med Biol 2013; 58:4513-34. [PMID: 23760161 DOI: 10.1088/0031-9155/58/13/4513] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ultrasonically activated phase-change contrast agents (PCCAs) based on perfluorocarbon droplets have been proposed for a variety of therapeutic and diagnostic clinical applications. When generated at the nanoscale, droplets may be small enough to exit the vascular space and then be induced to vaporize with high spatial and temporal specificity by externally-applied ultrasound. The use of acoustical techniques for optimizing ultrasound parameters for given applications can be a significant challenge for nanoscale PCCAs due to the contributions of larger outlier droplets. Similarly, optical techniques can be a challenge due to the sub-micron size of nanodroplet agents and resolution limits of optical microscopy. In this study, an optical method for determining activation thresholds of nanoscale emulsions based on the in vitro distribution of bubbles resulting from vaporization of PCCAs after single, short (<10 cycles) ultrasound pulses is evaluated. Through ultra-high-speed microscopy it is shown that the bubbles produced early in the pulse from vaporized droplets are strongly affected by subsequent cycles of the vaporization pulse, and these effects increase with pulse length. Results show that decafluorobutane nanoemulsions with peak diameters on the order of 200 nm can be optimally vaporized with short pulses using pressures amenable to clinical diagnostic ultrasound machines.
Collapse
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
| | | | | |
Collapse
|
42
|
Matsunaga TO, Sheeran PS, Luois S, Streeter JE, Mullin LB, Banerjee B, Dayton PA. Phase-change nanoparticles using highly volatile perfluorocarbons: toward a platform for extravascular ultrasound imaging. Theranostics 2012; 2:1185-98. [PMID: 23382775 PMCID: PMC3563153 DOI: 10.7150/thno.4846] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 11/02/2012] [Indexed: 12/20/2022] Open
Abstract
Recent efforts using perfluorocarbon (PFC) nanoparticles in conjunction with acoustic droplet vaporization has introduced the possibility of expanding the diagnostic and therapeutic capability of ultrasound contrast agents to beyond the vascular space. Our laboratories have developed phase-change nanoparticles (PCNs) from the highly volatile PFCs decafluorobutane (DFB, bp =-2 °C) and octafluoropropane (OFP, bp =-37 °C ) for acoustic droplet vaporization. Studies with commonly used clinical ultrasound scanners have demonstrated the ability to vaporize PCN emulsions with frequencies and mechanical indices that may significantly decrease tissue bioeffects. In addition, these contrast agents can be formulated to be stable at physiological temperatures and the perfluorocarbons can be mixed to modulate the balance between sensitivity to ultrasound and general stability. We herein discuss our recent efforts to develop finely-tuned diagnostic/molecular imaging agents for tissue interrogation. We discuss studies currently under investigation as well as potential diagnostic and therapeutic paradigms that may emerge as a result of formulating PCNs with low boiling point PFCs.
Collapse
|