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Azami RH, Forsberg F, Eisenbrey JR, Sarkar K. Acoustic response and ambient pressure sensitivity characterization of SonoVue for noninvasive pressure estimation. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:2636-2645. [PMID: 38629883 PMCID: PMC11026112 DOI: 10.1121/10.0025690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/21/2024] [Accepted: 03/27/2024] [Indexed: 04/20/2024]
Abstract
Subharmonic aided pressure estimation (SHAPE) is a noninvasive pressure measurement technique based on the pressure dependent subharmonic signal from contrast microbubbles. Here, SonoVue microbubble with a sulfur hexafluoride (SF6) core, was investigated for use in SHAPE. The study uses excitations of 25-700 kPa peak negative pressure (PNP) and 3 MHz frequency over eight pressurization cycles between atmospheric pressure and overpressures, ranging from 0 to 25 kPa (0 to 186 mm Hg). The SonoVue subharmonic response was characterized into two types. Unlike other microbubbles, SonoVue showed significant subharmonic signals at low excitations (PNPs, 25-400 kPa), denoted here as type I subharmonic. It linearly decreased with increasing overpressure (-0.52 dB/kPa at 100 kPa PNP). However, over multiple pressurization-depressurization cycles, type I subharmonic changed; its value at atmospheric pressure decreased over multiple cycles, and at later cycles, it recorded an increase in amplitude with overpressure (highest, +13 dB at 50 kPa PNP and 10 kPa overpressure). The subharmonic at higher excitations (PNP > 400 kPa), denoted here as type II subharmonic, showed a consistent decrease with the ambient pressure increase with strongest sensitivity of -0.4 dB/kPa at 500 kPa PNP.
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Affiliation(s)
- Roozbeh H Azami
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - John R Eisenbrey
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Kausik Sarkar
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052, USA
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2
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Malone CD, Fetzer DT, Monsky WL, Itani M, Mellnick VM, Velez PA, Middleton WD, Averkiou MA, Ramaswamy RS. Contrast-enhanced US for the Interventional Radiologist: Current and Emerging Applications. Radiographics 2021; 40:562-588. [PMID: 32125955 DOI: 10.1148/rg.2020190183] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
US is a powerful and nearly ubiquitous tool in the practice of interventional radiology. Use of contrast-enhanced US (CEUS) has gained traction in diagnostic imaging given the recent approval by the U.S. Food and Drug Administration (FDA) of microbubble contrast agents for use in the liver, such as sulfur hexafluoride lipid-type A microspheres. Adoption of CEUS by interventional radiologists can enhance not only procedure guidance but also preprocedure patient evaluation and assessment of treatment response across a wide spectrum of oncologic, vascular, and nonvascular procedures. In addition, the unique physical properties of microbubble contrast agents make them amenable as therapeutic vehicles in themselves, which can lay a foundation for future therapeutic innovations in the field in drug delivery, thrombolysis, and vascular flow augmentation. The purpose of this article is to provide an introduction to and overview of CEUS aimed at the interventional radiologist, highlighting its role before, during, and after frequently practiced oncologic and vascular interventions such as biopsy, ablation, transarterial chemoembolization, detection and control of hemorrhage, evaluation of transjugular intrahepatic portosystemic shunts (TIPS), detection of aortic endograft endoleak, thrombus detection and evaluation, evaluation of vascular malformations, lymphangiography, and percutaneous drain placement. Basic physical principles of CEUS, injection and scanning protocols, and logistics for practice implementation are also discussed. Early adoption of CEUS by the interventional radiology community will ensure rapid innovation of the field and development of future novel procedures. Online supplemental material is available for this article. ©RSNA, 2020.
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Affiliation(s)
- Christopher D Malone
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - David T Fetzer
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - Wayne L Monsky
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - Malak Itani
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - Vincent M Mellnick
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - Philip A Velez
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - William D Middleton
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - Michalakis A Averkiou
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
| | - Raja S Ramaswamy
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, CB 8131, St Louis, MO 63110 (C.D.M., M.I., V.M.M., P.A.V., W.D.M., R.S.R.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (D.T.F.); Department of Radiology, University of Washington Medical Center, Seattle, Wash (W.L.M.); and Department of Bioengineering, University of Washington, Seattle, Wash (M.A.A.)
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Keller SB, Sheeran PS, Averkiou MA. Cavitation Therapy Monitoring of Commercial Microbubbles With a Clinical Scanner. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:1144-1154. [PMID: 33112743 DOI: 10.1109/tuffc.2020.3034532] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to monitor cavitation activity during ultrasound and microbubble-mediated procedures is of high clinical value. However, there has been little reported literature comparing the cavitation characteristics of different clinical microbubbles, nor have current clinical scanners been used to perform passive cavitation detection in real time. The goal of this work was to investigate and characterize standard microbubble formulations (Optison, Sonovue, Sonazoid, and a custom microbubble made with similar components as Definity) with a custom passive cavitation detector (two confocal single-element focused transducers) and with a Philips EPIQ scanner with a C5-1 curvilinear probe passively listening. We evaluated three different methods for investigating cavitation thresholds, two from previously reported work and one developed in this work. For all three techniques, it was observed that the inertial cavitation thresholds were between 0.1 and 0.3 MPa for all agents when detected with both systems. Notably, we found that most microbubble formulations in bulk solution behaved generally similarly, with some differences. We show that these characteristics and thresholds are maintained when using a diagnostic ultrasound system for detecting cavitation activity. We believe that a systematic evaluation of the frequency response of the cavitation activity of different microbubbles in order to inform real-time therapy monitoring using a clinical ultrasound device could make an immediate clinical impact.
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Grundy M, Bau L, Hill C, Paverd C, Mannaris C, Kwan J, Crake C, Coviello C, Coussios C, Carlisle R. Improved therapeutic antibody delivery to xenograft tumors using cavitation nucleated by gas-entrapping nanoparticles. Nanomedicine (Lond) 2021; 16:37-50. [PMID: 33426913 DOI: 10.2217/nnm-2020-0263] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aims: Testing ultrasound-mediated cavitation for enhanced delivery of the therapeutic antibody cetuximab to tumors in a mouse model. Methods: Tumors with strong EGF receptor expression were grown bilaterally. Cetuximab was coadministered intravenously with cavitation nuclei, consisting of either the ultrasound contrast agent Sonovue or gas-stabilizing nanoscale SonoTran Particles. One of the two tumors was exposed to focused ultrasound. Passive acoustic mapping localized and monitored cavitation activity. Both tumors were then excised and cetuximab concentration was quantified. Results: Cavitation increased tumoral cetuximab concentration. When nucleated by Sonovue, a 2.1-fold increase (95% CI 1.3- to 3.4-fold) was measured, whereas SonoTran Particles gave a 3.6-fold increase (95% CI 2.3- to 5.8-fold). Conclusions: Ultrasound-mediated cavitation, especially when nucleated by nanoscale gas-entrapping particles, can noninvasively increase site-specific delivery of therapeutic antibodies to solid tumors.
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Affiliation(s)
- Megan Grundy
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
| | - Luca Bau
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
| | - Claudia Hill
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
| | - Catherine Paverd
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
| | - Christophoros Mannaris
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
| | - James Kwan
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK
| | - Calum Crake
- OxSonics Therapeutics, Oxford Science Park, Oxford OX4 4GA, UK
| | | | - Constantin Coussios
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
| | - Robert Carlisle
- Department of Engineering Science, Biomedical Ultrasonics, Biotherapy and Biopharmaceuticals Laboratory (BUBBL), Institute of Biomedical Engineering (IBME), University of Oxford, Old Road Campus Research Building, Headington, Oxford OX3 7DQ, UK
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5
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Dong W, Huang A, Huang J, Wu P, Guo S, Liu H, Qin M, Yang X, Zhang B, Wan M, Zong Y. Plasmid-loadable magnetic/ultrasound-responsive nanodroplets with a SPIO-NP dispersed perfluoropentane core and lipid shell for tumor-targeted intracellular plasmid delivery. Biomater Sci 2020; 8:5329-5345. [PMID: 32793943 DOI: 10.1039/d0bm00699h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Using ultrasound activating contrast agents to induce sonoporation is a potential strategy for effective lesion-targeted gene delivery. Previous reports have proven that submicron nanodroplets have a better advantage than microbubbles in that they can pass through tumor vasculature endothelial gaps by passive targeting; however, they cannot achieve an adequate dose in tumors to facilitate ultrasound-enhanced gene delivery. Additionally, a few studies focused on delivering macromolecular genetic materials (i.e. overexpression plasmid and CRISPR plasmid) have presented more unique advantages than small-molecular genetic materials (i.e. miRNA mimics, siRNA and shRNA etc.), such as enhancing the expression of target genes with long-term effectiveness. Thereby, we constructed novel plasmid-loadable magnetic/ultrasound-responsive nanodroplets, where superparamagnetic iron oxide nanoparticle dispersed perfluoropentane was encapsulated with lipids to which plasmids could be adhered, and branched polyethylenimine was used to protect the plasmids from enzymolysis. Furthermore, in vitro and in vivo studies were performed to verify the magnetic tumor-targeting ability of the plasmid-loadable magnetic/ultrasound-responsive nanodroplets and focused ultrasound enhanced intracellular plasmid delivery. The plasmid-loadable magnetic/ultrasound-responsive nanodroplets, carrying 16-19 plasmids per droplet, had desirable diameters less than 300 nm, and integrated the merits of excellent magnetic targeting capabilities and phase transition sensitivity to focused ultrasound. Under programmable focused ultrasound exposure, the plasmid-loadable magnetic/ultrasound-responsive nanodroplets underwent a phase-transition into echogenic microbubbles and the subsequent inertial cavitation of the microbubbles achieved an ∼40% in vitro plasmid delivery efficiency. Following intravenous administration, T2-weighted magnet resonance imaging, scanning electron microscopy and inductively coupled plasma optical emission spectrometry of the tumors showed significantly enhanced intratumoral accumulation of the plasmid-loadable magnetic/ultrasound-responsive nanodroplets under an external magnetic field. And a GFP ELISA assay and immunofluorescence staining indicated that focused ultrasound-induced inertial cavitation of the plasmid-loadable magnetic/ultrasound-responsive nanodroplets significantly enhanced the intracellular delivery of plasmids within the tumor after magnet-assisted accumulation, while only lower GFP levels were observed in the tumors on applying focused ultrasound or an external magnet alone. Taken together, utilizing the excellent plasmid-loadable magnetic/ultrasound-responsive nanodroplets combined with magnetism and ultrasound could efficiently deliver plasmids to cancer cells, which could be a potential strategy for macromolecular genetic material delivery in the clinic to treat cancer.
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Affiliation(s)
- Wei Dong
- 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, Shaanxi, China.
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6
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Keller SB, Suo D, Wang YN, Kenerson H, Yeung RS, Averkiou MA. Image-Guided Treatment of Primary Liver Cancer in Mice Leads to Vascular Disruption and Increased Drug Penetration. Front Pharmacol 2020; 11:584344. [PMID: 33101038 PMCID: PMC7554611 DOI: 10.3389/fphar.2020.584344] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/07/2020] [Indexed: 12/14/2022] Open
Abstract
Despite advances in interventional procedures and chemotherapeutic drug development, hepatocellular carcinoma (HCC) is still the fourth leading cause of cancer-related deaths worldwide with a <30% 5-year survival rate. This poor prognosis can be attributed to the fact that HCC most commonly occurs in patients with pre-existing liver conditions, rendering many treatment options too aggressive. Patient survival rates could be improved by a more targeted approach. Ultrasound-induced cavitation can provide a means for overcoming traditional barriers defining drug uptake. The goal of this work was to evaluate preclinical efficacy of image-guided, cavitation-enabled drug delivery with a clinical ultrasound scanner. To this end, ultrasound conditions (unique from those used in imaging) were designed and implemented on a Philips EPIQ and S5-1 phased array probe to produced focused ultrasound for cavitation treatment. Sonovue® microbubbles which are clinically approved as an ultrasound contrast agent were used for both imaging and cavitation treatment. A genetically engineered mouse model was bred and used as a physiologically relevant preclinical analog to human HCC. It was observed that image-guided and targeted microbubble cavitation resulted in selective disruption of the tumor blood flow and enhanced doxorubicin uptake and penetration. Histology results indicate that no gross morphological damage occurred as a result of this process. The combination of these effects may be exploited to treat HCC and other challenging malignancies and could be implemented with currently available ultrasound scanners and reagents.
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Affiliation(s)
- Sara B Keller
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Dingjie Suo
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Yak-Nam Wang
- Applied Physics Laboratory, University of Washington, Seattle, WA, United States
| | - Heidi Kenerson
- Department of Surgery, University of Washington, Seattle, WA, United States
| | - Raymond S Yeung
- Department of Surgery, University of Washington, Seattle, WA, United States
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7
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Lattwein KR, Shekhar H, Kouijzer JJP, van Wamel WJB, Holland CK, Kooiman K. Sonobactericide: An Emerging Treatment Strategy for Bacterial Infections. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:193-215. [PMID: 31699550 PMCID: PMC9278652 DOI: 10.1016/j.ultrasmedbio.2019.09.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 09/03/2019] [Accepted: 09/16/2019] [Indexed: 05/04/2023]
Abstract
Ultrasound has been developed as both a diagnostic tool and a potent promoter of beneficial bio-effects for the treatment of chronic bacterial infections. Bacterial infections, especially those involving biofilm on implants, indwelling catheters and heart valves, affect millions of people each year, and many deaths occur as a consequence. Exposure of microbubbles or droplets to ultrasound can directly affect bacteria and enhance the efficacy of antibiotics or other therapeutics, which we have termed sonobactericide. This review summarizes investigations that have provided evidence for ultrasound-activated microbubble or droplet treatment of bacteria and biofilm. In particular, we review the types of bacteria and therapeutics used for treatment and the in vitro and pre-clinical experimental setups employed in sonobactericide research. Mechanisms for ultrasound enhancement of sonobactericide, with a special emphasis on acoustic cavitation and radiation force, are reviewed, and the potential for clinical translation is discussed.
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Affiliation(s)
- Kirby R Lattwein
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
| | - Himanshu Shekhar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Joop J P Kouijzer
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Willem J B van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Christy K Holland
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Klazina Kooiman
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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8
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Gnanaskandan A, Hsiao CT, Chahine G. Modeling of Microbubble-Enhanced High-Intensity Focused Ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1743-1761. [PMID: 30982546 PMCID: PMC6555682 DOI: 10.1016/j.ultrasmedbio.2019.02.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/05/2019] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
Heat enhancement at the target in a high intensity focused ultrasound (HIFU) field is investigated by considering the effects of the injection of microbubbles in the vicinity of the tumor to be ablated. The interaction between the bubble cloud and the HIFU field is investigated using a 3-D numerical model. The propagation of non-linear ultrasonic waves in the tissue or in a phantom medium is modeled using the compressible Navier-Stokes equations on a fixed Eulerian grid, while the microbubbles dynamics and motion are modeled as discrete singularities, which are tracked in a Lagrangian framework. These two models are coupled to each other such that both the acoustic field and the bubbles influence each other. The resulting temperature rise in the field is calculated by solving a heat transfer equation applied over a much longer time scale. The compressible continuum part of the model is validated by conducting axisymmetric HIFU simulations without microbubbles and comparing the pressure and temperature fields against available experiments. The coupled Eulerian-Lagrangian approach is then validated against existing experiments conducted with a phantom tissue. The bubbles are distributed randomly in a 3-D fashion inside a cylindrical volume, while the background acoustic field is assumed axisymmetric. The presence of microbubbles modifies the ultrasound field in the focal region and significantly enhances heat deposition. The various mechanisms through which heat deposition is increased are then examined. Among these effects, viscous damping of the bubble oscillations is found to be the main contributor to the enhanced heat deposition. The effects of the initial void fraction in the cloud are then sought by considering the changes in the attenuation of the primary ultrasonic wave and the modifications of the enhanced heat deposition in the focal region. It is observed that although high bubble void fractions lead to increased heat deposition, they also cause significant pre-focal heating because of acoustic shielding. The effects of the microbubble cloud size and its location in the focal region are studied, and the effects of these parameters in altering the temperature rise and the location of the temperature peak are discussed. It is found that concentrating the bubbles adjacent to the focus and farther away from the acoustic source leads to effective heat deposition. Finally, the presence of a shell at the bubble surface, as in contrast agents, is seen to reduce heat deposition by restraining bubble oscillations.
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9
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Mannaris C, Bau L, Grundy M, Gray M, Lea-Banks H, Seth A, Teo B, Carlisle R, Stride E, Coussios CC. Microbubbles, Nanodroplets and Gas-Stabilizing Solid Particles for Ultrasound-Mediated Extravasation of Unencapsulated Drugs: An Exposure Parameter Optimization Study. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:954-967. [PMID: 30655109 DOI: 10.1016/j.ultrasmedbio.2018.10.033] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/24/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
Ultrasound-induced cavitation has been proposed as a strategy to tackle the challenge of inadequate extravasation, penetration and distribution of therapeutics into tumours. Here, the ability of microbubbles, droplets and solid gas-trapping particles to facilitate mass transport and extravasation of a model therapeutic agent following ultrasound-induced cavitation is investigated. Significant extravasation and penetration depths on the order of millimetres are achieved with all three agents, including the range of pressures and frequencies achievable with existing clinical ultrasound systems. Deeper but highly directional extravasation was achieved with frequencies of 1.6 and 3.3 MHz compared with 0.5 MHz. Increased extravasation was observed with increasing pulse length and exposure time, while an inverse relationship is observed with pulse repetition frequency. No significant cell death or any haemolytic activity in human blood was observed at clinically relevant concentrations for any of the agents. Overall, solid gas-trapping nanoparticles were found to enable the most extensive extravasation for the lowest input acoustic energy, followed by microbubbles and then droplets. The ability of these agents to produce sustained inertial cavitation activity whilst being small enough to follow the drug out of the circulation and into diseased tissue, combined with a good safety profile and the possibility of real-time monitoring, offers considerable potential for enhanced drug delivery of unmodified drugs in oncological and other biomedical applications.
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Affiliation(s)
- Christophoros Mannaris
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Luca Bau
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Megan Grundy
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Michael Gray
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Harriet Lea-Banks
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Anjali Seth
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Boon Teo
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Robert Carlisle
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Eleanor Stride
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom
| | - Constantin C Coussios
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Headington, Oxford, United Kingdom.
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van Ballegooie C, Man A, Win M, Yapp DT. Spatially Specific Liposomal Cancer Therapy Triggered by Clinical External Sources of Energy. Pharmaceutics 2019; 11:E125. [PMID: 30884786 PMCID: PMC6470770 DOI: 10.3390/pharmaceutics11030125] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 11/25/2022] Open
Abstract
This review explores the use of energy sources, including ultrasound, magnetic fields, and external beam radiation, to trigger the delivery of drugs from liposomes in a tumor in a spatially-specific manner. Each section explores the mechanism(s) of drug release that can be achieved using liposomes in conjunction with the external trigger. Subsequently, the treatment's formulation factors are discussed, highlighting the parameters of both the therapy and the medical device. Additionally, the pre-clinical and clinical trials of each triggered release method are explored. Lastly, the advantages and disadvantages, as well as the feasibility and future outlook of each triggered release method, are discussed.
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Affiliation(s)
- Courtney van Ballegooie
- Experimental Therapeutics, BC Cancer, Vancouver, BC V5Z 1L3, Canada.
- Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| | - Alice Man
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| | - Mi Win
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
| | - Donald T Yapp
- Experimental Therapeutics, BC Cancer, Vancouver, BC V5Z 1L3, Canada.
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Keller S, Bruce M, Averkiou MA. Ultrasound Imaging of Microbubble Activity during Sonoporation Pulse Sequences. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:833-845. [PMID: 30638695 PMCID: PMC6690385 DOI: 10.1016/j.ultrasmedbio.2018.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/21/2018] [Accepted: 11/26/2018] [Indexed: 05/28/2023]
Abstract
Ultrasound-mediated drug delivery using the mechanical action of oscillating and/or collapsing microbubbles has been studied on many different experimental platforms, both in vitro and in vivo; however, the mechanisms remain to be elucidated. Many groups use sterile, enclosed chambers, such as Opticells and Clinicells, to optimize acoustic parameters in vitro needed for effective drug delivery in vivo, as well as for mechanistic investigation of sonoporation or the use of sound to permeate cell membranes. In these containers, cell monolayers are seeded on one side, and the remainder of the volume is filled with a solution containing microbubbles and a model drug. Ultrasound is then applied to study the effect of different parameters on model drug uptake in cell monolayers. Despite the simplicity of this system, the field has been unable to appropriately address what parameters and microbubble concentrations are most effective at enhancing drug uptake and minimizing cellular toxicity. In this work, a common in vitro sonoporation experimental setup was characterized through quantitative analysis of microbubble-dependent acoustic attenuation in combination with high-frame-rate and high-resolution imaging of bubble activity during sonoporation pulse sequences. The goal was to visualize the effect that ultrasound parameters have on microbubble activity. It was observed that under literature-derived sonoporation conditions (0.1-1 MPa, 20-1000 cycles and 10,000 to 10,000,000 microbubbles/mL), there is strong and non-linear acoustic attenuation, as well as bubble destruction, gas diffusion and bubble motion resulting in spatiotemporal pressure and concentration gradients. Ultimately, it was found that the acoustic conditions in common in vitro sonoporation setups are much more complex and confounding than often assumed.
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Affiliation(s)
- Sara Keller
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Matthew Bruce
- Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
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12
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Improvement of Detection Sensitivity of Microbubbles as Sensors to Detect Ambient Pressure. SENSORS 2018; 18:s18124083. [PMID: 30469461 PMCID: PMC6308843 DOI: 10.3390/s18124083] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/14/2018] [Accepted: 11/19/2018] [Indexed: 01/16/2023]
Abstract
Microbubbles are considered a promising tool for noninvasive estimation of local blood pressure. It is reported that the subharmonic scattering amplitude of microbubbles decreases by 9 to 12 dB when immersed in the media under an ambient pressure variation from 0 to 180 mmHg. However, the pressure sensitivity still needs to be improved to satisfy clinical diagnostic requirements. Here, we investigated the effects of acoustic parameters on the pressure sensitivity of microbubbles through measuring the acoustic attenuation and scattering properties of commercially available SonoVue microbubbles. Our results showed that the first harmonic, subharmonic, and ultraharmonic amplitudes of microbubbles were reduced by 6.6 dB, 10.9 dB, and 9.3 dB at 0.225 mechanical index (MI), 4.6 dB, 19.8 dB, and 12.3 dB at 0.25 MI, and 18.5 dB, 17.6 dB, and 12.6 dB at 0.3 MI, respectively, when the ambient pressure increased from 0 to 180 mmHg. Our finding revealed that a moderate MI (0.25–0.4) exciting microbubbles could significantly improve their sensitivities to detect ambient pressure.
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13
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Skachkov I, Luan Y, van Tiel ST, van der Steen AFW, de Jong N, Bernsen MR, Kooiman K. SPIO labeling of endothelial cells using ultrasound and targeted microbubbles at diagnostic pressures. PLoS One 2018; 13:e0204354. [PMID: 30235336 PMCID: PMC6147550 DOI: 10.1371/journal.pone.0204354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/06/2018] [Indexed: 02/07/2023] Open
Abstract
In vivo cell tracking of therapeutic, tumor, and endothelial cells is an emerging field and a promising technique for imaging cardiovascular disease and cancer development. Site-specific labeling of endothelial cells with the MRI contrast agent superparamagnetic iron oxide (SPIO) in the absence of toxic agents is challenging. Therefore, the aim of this in vitro study was to find optimal parameters for efficient and safe SPIO-labeling of endothelial cells using ultrasound-activated CD31-targeted microbubbles for future MRI tracking. Ultrasound at a frequency of 1 MHz (10,000 cycles, repetition rate of 20 Hz) was used for varying applied peak negative pressures (10–160 kPa, i.e. low mechanical index (MI) of 0.01–0.16), treatment durations (0–30 s), time of SPIO addition (-5 min– 15 min with respect to the start of the ultrasound), and incubation time after SPIO addition (5 min– 3 h). Iron specific Prussian Blue staining in combination with calcein-AM based cell viability assays were applied to define the most efficient and safe conditions for SPIO-labeling. Optimal SPIO labeling was observed when the ultrasound parameters were 40 kPa peak negative pressure (MI 0.04), applied for 30 s just before SPIO addition (0 min). Compared to the control, this resulted in an approximate 12 times increase of SPIO uptake in endothelial cells in vitro with 85% cell viability. Therefore, ultrasound-activated targeted ultrasound contrast agents show great potential for effective and safe labeling of endothelial cells with SPIO.
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Affiliation(s)
- Ilya Skachkov
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
| | - Ying Luan
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
| | - Sandra T. van Tiel
- Department of Radiology & Nucleair Medicine, Erasmus MC, Rotterdam, the Netherlands
| | - Antonius F. W. van der Steen
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
- Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Nico de Jong
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
- Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Monique R. Bernsen
- Department of Radiology & Nucleair Medicine, Erasmus MC, Rotterdam, the Netherlands
| | - Klazina Kooiman
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
- * E-mail:
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14
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Mannaris C, Teo BM, Seth A, Bau L, Coussios C, Stride E. Gas-Stabilizing Gold Nanocones for Acoustically Mediated Drug Delivery. Adv Healthc Mater 2018; 7:e1800184. [PMID: 29696808 DOI: 10.1002/adhm.201800184] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/15/2018] [Indexed: 01/27/2023]
Abstract
The efficient penetration of drugs into tumors is a major challenge that remains unmet. Reported herein is a strategy to promote extravasation and enhanced penetration using inertial cavitation initiated by focused ultrasound and cone-shaped gold nanoparticles that entrap gas nanobubbles. The cones are capable of initiating inertial cavitation under pressures and frequencies achievable with existing clinical ultrasound systems and of promoting extravasation and delivery of a model large therapeutic molecule in an in vitro tissue mimicking flow phantom, achieving penetration depths in excess of 2 mm. Ease of functionalization and intrinsic imaging capabilities provide gold with significant advantages as a material for biomedical applications. The cones show neither cytotoxicity in Michigan Cancer Foundation (MCF)-7 cells nor hemolytic activity in human blood at clinically relevant concentrations and are found to be colloidally stable for at least 5 d at 37 °C and several months at 4 °C.
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Affiliation(s)
- Christophoros Mannaris
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - Boon M Teo
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
- Interdisciplinary Nanoscience Center (iNANO), The iNANO House, Aarhus University, Gustav Wieds Vej 14, DK-8000, Aarhus C, Denmark
- School of Chemistry, Monash University, 19 Rainforest Walk, Clayton, VIC, 3800, Australia
| | - Anjali Seth
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - Luca Bau
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - Constantin Coussios
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - Eleanor Stride
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
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15
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Pereno V, Aron M, Vince O, Mannaris C, Seth A, de Saint Victor M, Lajoinie G, Versluis M, Coussios C, Carugo D, Stride E. Layered acoustofluidic resonators for the simultaneous optical and acoustic characterisation of cavitation dynamics, microstreaming, and biological effects. BIOMICROFLUIDICS 2018; 12:034109. [PMID: 29887932 PMCID: PMC5976496 DOI: 10.1063/1.5023729] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 05/09/2018] [Indexed: 05/22/2023]
Abstract
The study of the effects of ultrasound-induced acoustic cavitation on biological structures is an active field in biomedical research. Of particular interest for therapeutic applications is the ability of oscillating microbubbles to promote both cellular and tissue membrane permeabilisation and to improve the distribution of therapeutic agents in tissue through extravasation and convective transport. The mechanisms that underpin the interaction between cavitating agents and tissues are, however, still poorly understood. One challenge is the practical difficulty involved in performing optical microscopy and acoustic emissions monitoring simultaneously in a biologically compatible environment. Here we present and characterise a microfluidic layered acoustic resonator (μLAR) developed for simultaneous ultrasound exposure, acoustic emissions monitoring, and microscopy of biological samples. The μLAR facilitates in vitro ultrasound experiments in which measurements of microbubble dynamics, microstreaming velocity fields, acoustic emissions, and cell-microbubble interactions can be performed simultaneously. The device and analyses presented provide a means of performing mechanistic in vitro studies that may benefit the design of predictable and effective cavitation-based ultrasound treatments.
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Affiliation(s)
- V. Pereno
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - M. Aron
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - O. Vince
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - C. Mannaris
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - A. Seth
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - M. de Saint Victor
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - G. Lajoinie
- Physics of Fluids Group, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - M. Versluis
- Physics of Fluids Group, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - C. Coussios
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - D. Carugo
- Authors to whom correspondence should be addressed: and
| | - E. Stride
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
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16
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van Rooij T, Skachkov I, Beekers I, Lattwein KR, Voorneveld JD, Kokhuis TJ, Bera D, Luan Y, van der Steen AF, de Jong N, Kooiman K. Viability of endothelial cells after ultrasound-mediated sonoporation: Influence of targeting, oscillation, and displacement of microbubbles. J Control Release 2016; 238:197-211. [DOI: 10.1016/j.jconrel.2016.07.037] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/20/2016] [Accepted: 07/24/2016] [Indexed: 10/21/2022]
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17
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Chen X, Wang J, Pacella JJ, Villanueva FS. Dynamic Behavior of Microbubbles during Long Ultrasound Tone-Burst Excitation: Mechanistic Insights into Ultrasound-Microbubble Mediated Therapeutics Using High-Speed Imaging and Cavitation Detection. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:528-538. [PMID: 26603628 PMCID: PMC4698009 DOI: 10.1016/j.ultrasmedbio.2015.09.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/11/2015] [Accepted: 09/17/2015] [Indexed: 05/24/2023]
Abstract
Ultrasound (US)-microbubble (MB)-mediated therapies have been found to restore perfusion and enhance drug/gene delivery. On the presumption that MBs do not persist during long US exposure under high acoustic pressures, most schemes use short US pulses when a high US pressure is employed. However, we recently observed an enhanced thrombolytic effect using long US pulses at high acoustic pressures. Therefore, we explored the fate of MBs during long tone-burst exposures (5 ms) at various acoustic pressures and MB concentrations via direct high-speed optical observation and passive cavitation detection. MBs first underwent stable or inertial cavitation depending on the acoustic pressure and then formed gas-filled clusters that continued to oscillate, break up and form new clusters. Cavitation detection confirmed continued, albeit diminishing, acoustic activity throughout the 5-ms US excitation. These data suggest that persisting cavitation activity during long tone bursts may confer additional therapeutic effects.
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Affiliation(s)
- Xucai Chen
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Jianjun Wang
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - John J Pacella
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Flordeliza S Villanueva
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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18
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Keravnou CP, Mannaris C, Averkiou MA. Accurate measurement of microbubble response to ultrasound with a diagnostic ultrasound scanner. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2015; 62:176-184. [PMID: 25585401 DOI: 10.1109/tuffc.2014.006664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ultrasound and microbubbles are often used to enhance drug delivery and the suggested mechanisms are extravasation and sonoporation. Drug delivery schemes with ultrasound and microbubbles at both low and high acoustic amplitudes have been suggested. A diagnostic ultrasound scanner may play a double role as both an imaging and a therapy device. It was not possible to accurately measure microbubble response with an ultrasound scanner for a large range of acoustic pressures and microbubble concentrations until now, mainly because of signal saturation issues. A method for continuously adjusting the receive gain of a scanner and limiting signal saturation was developed to accurately measure backscattered echoes from microbubbles for mechanical indexes (MIs) up to 2.1. The intensity of backscattered echoes from microbubbles increased quarticly with MI without reaching any limit. The signal intensity from microbubbles was found to be linear with concentration at both low and high MIs. However, at very high concentrations, acoustic shadowing occurs which limits the delivered acoustic pressure in deeper areas. The contrastto- tissue ratio was also measured and found to stay constant with MI. These results can be used to better guide drug delivery approaches and to also develop imaging techniques for therapy procedures.
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19
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Mechanisms of microbubble-facilitated sonoporation for drug and gene delivery. Ther Deliv 2014; 5:467-86. [PMID: 24856171 DOI: 10.4155/tde.14.10] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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20
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Skachkov I, Luan Y, van der Steen AFW, de Jong N, Kooiman K. Targeted microbubble mediated sonoporation of endothelial cells in vivo. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2014; 61:1661-1667. [PMID: 25265175 DOI: 10.1109/tuffc.2014.006440] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ultrasound contrast agents as drug-delivery systems are an emerging field. Recently, we reported that targeted microbubbles are able to sonoporate endothelial cells in vitro. In this study, we investigated whether targeted microbubbles can also induce sonoporation of endothelial cells in vivo, thereby making it possible to combine molecular imaging and drug delivery. Live chicken embryos were chosen as the in vivo model. αvß3-targeted microbubbles attached to the vessel wall of the chicken embryo were insonified at 1 MHz at 150 kPa (1 × 10,000 cycles) and at 200 kPa (1 × 1000 cycles) peak negative acoustic pressure. Sonoporation was studied by intravital microscopy using the model drug propidium iodide (PI). Endothelial cell PI uptake was observed in 48% of microbubble-vessel-wall complexes at 150 kPa (n = 140) and in 33% at 200 kPa (n = 140). Efficiency of PI uptake depended on the local targeted microbubble concentration and increased up to 80% for clusters of 10 to 16 targeted microbubbles. Ultrasound or targeted microbubbles alone did not induce PI uptake. This intravital microscopy study reveals that sonoporation can be visualized and induced in vivo using targeted microbubbles.
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21
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Razavi A, Clement D, Fowler RA, Birer A, Chavrier F, Mestas JL, Romano F, Chapelon JY, Béglé A, Lafon C. Contribution of inertial cavitation in the enhancement of in vitro transscleral drug delivery. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1216-1227. [PMID: 24613634 DOI: 10.1016/j.ultrasmedbio.2013.12.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 10/08/2013] [Accepted: 12/31/2013] [Indexed: 06/03/2023]
Abstract
In ocular drug delivery, the sclera is a promising pathway for administering drugs to both the anterior and posterior segments of the eye. Due to the low permeability of the sclera, however, efficient drug delivery is challenging. In this study, pulsed ultrasound (US) was investigated as a potential method for enhancing drug delivery to the eye through the sclera. The permeability of rabbit scleral tissue to a model drug compound, sodium fluorescein, was measured after US-irradiation at 1.1 MHz using time-averaged acoustic powers of 0.5-5.4 W (6.8-12.8 MPa peak negative pressure), with a fixed duty cycle of 2.5% for two different pulse repetition frequencies of 100 and 1000 Hz. Acoustic cavitation activity was measured during exposures using a passive cavitation detector and was used to quantify the level of bubble activity. A correlation between the amount of cavitation activity and the enhancement of scleral permeability was demonstrated with a significant enhancement in permeability of US exposed samples compared to controls. Transmission electron microscopy showed no evidence of significant alteration in viability of tissue exposed to US exposures. A pulsed US protocol designed to maximum cavitation activity may therefore be a viable method for enhancing drug delivery to the eye.
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Affiliation(s)
- Arash Razavi
- Inserm, Unité 1032, Lab TAU, Lyon, France; EyeTechCare, Rillieux la Pape, France.
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22
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Mannaris C, Efthymiou E, Meyre ME, Averkiou MA. In vitro localized release of thermosensitive liposomes with ultrasound-induced hyperthermia. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:2011-2020. [PMID: 23972488 DOI: 10.1016/j.ultrasmedbio.2013.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 05/24/2013] [Accepted: 06/02/2013] [Indexed: 06/02/2023]
Abstract
Localized drug delivery with ultrasound-induced hyperthermia can enhance the therapeutic index of chemotherapeutic drugs by improving efficacy and reducing systemic toxicity. A novel in vitro method for the activation of drug-loaded thermosensitive liposomes is described. In particular, a dual-compartment, acoustically transparent container is used in which thermosensitive liposomes suspended in cell culture medium are immersed in a thermally absorptive medium, glycerol. Hyperthermia is induced with ultrasound in the glycerol, which in turn heats the culture medium by thermal conduction. The method approximately mimics the in vivo scenario of thermosensitive liposomes collected in the interstitial spaces of tumors, where ultrasound induces hyperthermia in the tumor tissue, which in turn heats the thermosensitive liposomes by conduction and induces release of the encapsulated drug. The acoustic conditions for the desired hyperthermia are derived theoretically and validated experimentally. Eighty percent release of doxorubicin from thermosensitive liposomes is achieved.
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Affiliation(s)
- Christophoros Mannaris
- Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus
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23
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Cochran M, Wheatley MA. In vitro gene delivery with ultrasound-triggered polymer microbubbles. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:1102-19. [PMID: 23562023 PMCID: PMC3683598 DOI: 10.1016/j.ultrasmedbio.2013.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/16/2012] [Accepted: 01/22/2013] [Indexed: 05/05/2023]
Abstract
In the work described here, gene delivery using polymer microbubbles triggered by ultrasound in vitro was investigated. The effects of pressure amplitude (0-2 MPa), center frequency (1-5 MHz), pulse length (3-12,000 μs), pulse repetition frequency (5-20,000 Hz) and exposure time (0-30 s) on transfection efficiency and cell viability were examined. The effects of radiation force, calcium ion concentration and timing of treatments were also examined. Cells were successfully transfected with pressure amplitudes as low as 250 kPa. Transfection was most efficient at lower frequencies and longer pulse lengths, with a transfection efficiency of 24.2 ± 2.0% achieved using a center frequency of 1 MHz, pressure amplitude of 1 MPa, pulse length of 12,000 μs and pulse repetition frequency of 5 Hz. Gene delivery was also affected by the extracellular calcium ion concentration and the timing of treatments.
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Affiliation(s)
| | - Margaret A. Wheatley
- Corresponding author: Margaret A. Wheatley, Ph.D., School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, Tel: (215) 895 2232, Fax: (215) 895 4983,
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24
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Abstract
Time and space controlled drug delivery still remains a huge challenge in medicine. A novel approach that could offer a solution is ultrasound guided drug delivery. “Ultrasonic drug delivery” is often based on the use of small gas bubbles (so-called microbubbles) that oscillate and cavitate upon exposure to ultrasound waves. Some microbubbles are FDA approved contrast agents for ultrasound imaging and are nowadays widely investigated as promising drug carriers. Indeed, it has been observed that upon exposure to ultrasound waves, microbubbles may (a) release the encapsulated drugs and (b) simultaneously change the structure of the cell membranes in contact with the microbubbles which may facilitate drug entrance into cells. This review aims to highlight (a) major factors known so far which affect ultrasonic drug delivery (like the structure of the microbubbles, acoustic settings, etc.) and (b) summarizes the recent preclinical progress in this field together with a number of promising new concepts and applications.
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25
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Zhao YZ, Du LN, Lu CT, Jin YG, Ge SP. Potential and problems in ultrasound-responsive drug delivery systems. Int J Nanomedicine 2013; 8:1621-33. [PMID: 23637531 PMCID: PMC3635663 DOI: 10.2147/ijn.s43589] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Ultrasound is an important local stimulus for triggering drug release at the target tissue. Ultrasound-responsive drug delivery systems (URDDS) have become an important research focus in targeted therapy. URDDS include many different formulations, such as microbubbles, nanobubbles, nanodroplets, liposomes, emulsions, and micelles. Drugs that can be loaded into URDDS include small molecules, biomacromolecules, and inorganic substances. Fields of clinical application include anticancer therapy, treatment of ischemic myocardium, induction of an immune response, cartilage tissue engineering, transdermal drug delivery, treatment of Huntington’s disease, thrombolysis, and disruption of the blood–brain barrier. This review focuses on recent advances in URDDS, and discusses their formulations, clinical application, and problems, as well as a perspective on their potential use in the future.
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Affiliation(s)
- Ying-Zheng Zhao
- Wenzhou Medical College, Wenzhou City, Zhejiang Province, People's Republic of China
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