1
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Yusefi H, Helfield B. Subharmonic resonance of phospholipid coated ultrasound contrast agent microbubbles. ULTRASONICS SONOCHEMISTRY 2024; 102:106753. [PMID: 38217906 PMCID: PMC10825773 DOI: 10.1016/j.ultsonch.2024.106753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/13/2023] [Accepted: 01/01/2024] [Indexed: 01/15/2024]
Abstract
Phospholipid encapsulated ultrasound contrast agents have proven to be a powerful addition in diagnostic imaging and show emerging applications in targeted therapy due to their resonant and nonlinear scattering. Microbubble response is affected by their intrinsic (e.g. bubble size, encapsulation physics) and extrinsic (e.g. boundaries) factors. One of the major intrinsic factors at play affecting microbubble vibration dynamics is the initial phospholipid packing of the lipid encapsulation. Here, we examine how the initial phospholipid packing affects the subharmonic response of either individual or a system of two closely-placed microbubbles. We employ a finite element model to investigate the change in subharmonic resonance under 'small' and 'large' radial excursions. For microbubbles ranging between 1.5 and 2.5 µm in diameter and in its elastic state (σ0 = 0.01 N/m), we demonstrate up to a 10 % shift towards lower frequencies in the peak subharmonic response as the radial excursion increases. However, for a bubble initially in its buckled state (σ0 = 0 N/m), we observe a maximum shift of 8 % towards higher frequencies as the radial excursion increases over the same range of bubble sizes - the opposite trend. We studied the same scenario for a system of two individual microbubbles for which we saw similar results. For microbubbles that are initially in their elastic state, in both cases of a) two identically sized bubbles and b) a bubble in proximity to a smaller bubble, we observed a 6 % and 9 % shift towards lower frequencies respectively; while in the case of a neighboring larger bubble no change in subharmonic resonance frequency was observed. Microbubbles that are initially in a buckled state exert no change, 5 % and 19 % shift towards higher frequencies, in two-bubble systems consisting of a) same-size, b) smaller, and c) larger neighboring bubble respectively. Furthermore, we examined the effect of two adjacent bubbles with non-equal initial phospholipid states. The results presented here have important implications in ultrasound contrast agent applications.
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Affiliation(s)
- Hossein Yusefi
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Brandon Helfield
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada; Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
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2
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Zhao X, Wright A, Goertz DE. An optical and acoustic investigation of microbubble cavitation in small channels under therapeutic ultrasound conditions. ULTRASONICS SONOCHEMISTRY 2023; 93:106291. [PMID: 36640460 PMCID: PMC9852793 DOI: 10.1016/j.ultsonch.2023.106291] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/22/2022] [Accepted: 01/04/2023] [Indexed: 06/04/2023]
Abstract
Therapeutic focused ultrasound in combination with encapsulated microbubbles is being widely investigated for its ability to elicit bioeffects in the microvasculature, such as transient permeabilization for drug delivery or at higher pressures to achieve 'antivascular' effects. While it is well established that the behaviors of microbubbles are altered when they are situated within sufficiently small vessels, there is a paucity of data examining how the bubble population dynamics and emissions change as a function of channel (vessel) diameter over a size range relevant to therapeutic ultrasound, particularly at pressures relevant to antivascular ultrasound. Here we use acoustic emissions detection and high-speed microscopy (10 kframes/s) to examine the behavior of a polydisperse clinically employed agent (Definity®) in wall-less channels as their diameters are scaled from 1200 to 15 µm. Pressures are varied from 0.1 to 3 MPa using either a 5 ms pulse or a sequence of 0.1 ms pulses spaced at 1 ms, both of which have been previously employed in an in vivo context. With increasing pressure, the 1200 µm channel - on the order of small arteries and veins - exhibited inertial cavitation, 1/2 subharmonics and 3/2 ultraharmonics, consistent with numerous previous reports. The 200 and 100 µm channels - in the size range of larger microvessels less affected by therapeutic focused ultrasound - exhibited a distinctly different behavior, having muted development of 1/2 subharmonics and 3/2 ultraharmonics and reduced persistence. These were associated with radiation forces displacing bubbles to the distal wall and inducing clusters that then rapidly dissipated along with emissions. As the diameter transitioned to 50 and then 15 µm - a size regime that is most relevant to therapeutic focused ultrasound - there was a higher threshold for the onset of inertial cavitation as well as subharmonics and ultraharmonics, which importantly had more complex orders that are not normally reported. Clusters also occurred in these channels (e.g. at 3 MPa, the mean lateral and axial sizes were 23 and 72 µm in the 15 µm channel; 50 and 90 µm in the 50 µm channel), however in this case they occupied the entire lumens and displaced the wall boundaries. Damage to the 15 µm channel was observed for both pulse types, but at a lower pressure for the long pulse. Experiments conducted with a 'nanobubble' (<0.45 µm) subpopulation of Definity followed broadly similar features to 'native' Definity, albeit at a higher pressure threshold for inertial cavitation. These results provide new insights into the behavior of microbubbles in small vessels at higher pressures and have implications for therapeutic focused ultrasound cavitation monitoring and control.
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Affiliation(s)
- Xiaoxiao Zhao
- Department of Medical Biophysics, University of Toronto, M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Ave, Toronto M4N 3M5, Canada.
| | - Alex Wright
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto M4N 3M5, Canada
| | - David E Goertz
- Department of Medical Biophysics, University of Toronto, M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Ave, Toronto M4N 3M5, Canada.
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3
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Spiekhout S, Voorneveld J, van Elburg B, Renaud G, Segers T, Lajoinie GPR, Versluis M, Verweij MD, de Jong N, Bosch JG. Time-resolved absolute radius estimation of vibrating contrast microbubbles using an acoustical camera. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:3993. [PMID: 35778226 DOI: 10.1121/10.0011619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Ultrasound (US) contrast agents consist of microbubbles ranging from 1 to 10 μm in size. The acoustical response of individual microbubbles can be studied with high-frame-rate optics or an "acoustical camera" (AC). The AC measures the relative microbubble oscillation while the optical camera measures the absolute oscillation. In this article, the capabilities of the AC are extended to measure the absolute oscillations. In the AC setup, microbubbles are insonified with a high- (25 MHz) and low-frequency US wave (1-2.5 MHz). Other than the amplitude modulation (AM) from the relative size change of the microbubble (employed in Renaud, Bosch, van der Steen, and de Jong (2012a). "An 'acoustical camera' for in vitro characterization of contrast agent microbubble vibrations," Appl. Phys. Lett. 100(10), 101911, the high-frequency response from individual vibrating microbubbles contains a phase modulation (PM) from the microbubble wall displacement, which is the extension described here. The ratio of PM and AM is used to determine the absolute radius, R0. To test this sizing, the size distributions of two monodisperse microbubble populations ( R = 2.1 and 3.5 μm) acquired with the AC were matched to the distribution acquired with a Coulter counter. As a result of measuring the absolute size of the microbubbles, this "extended AC" can capture the full radial dynamics of single freely floating microbubbles with a throughput of hundreds of microbubbles per hour.
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Affiliation(s)
- Sander Spiekhout
- Biomedical Engineering, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jason Voorneveld
- Biomedical Engineering, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Benjamin van Elburg
- Physics of Fluids Group, Department of Science and Technology, MESA+ Institute for Nanotechnology and Technical Medical (TechMed) Center, University of Twente, Enschede, The Netherlands
| | - Guillaume Renaud
- Laboratory of Medical Imaging, Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | - Tim Segers
- Biomedical and Environmental Sensor Systems (BIOS) Lab-on-a-Chip Group, Max Planck Center for Complex Fluid Dynamics, University of Twente, Enschede, The Netherlands
| | - Guillaume P R Lajoinie
- Physics of Fluids Group, Department of Science and Technology, MESA+ Institute for Nanotechnology and Technical Medical (TechMed) Center, University of Twente, Enschede, The Netherlands
| | - Michel Versluis
- Physics of Fluids Group, Department of Science and Technology, MESA+ Institute for Nanotechnology and Technical Medical (TechMed) Center, University of Twente, Enschede, The Netherlands
| | - Martin D Verweij
- Laboratory of Medical Imaging, Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | - Nico de Jong
- Laboratory of Medical Imaging, Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | - Johannes G Bosch
- Biomedical Engineering, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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4
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Jing B, Lindsey BD. Very Low Frequency Radial Modulation for Deep Penetration Contrast-Enhanced Ultrasound Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:530-545. [PMID: 34972572 DOI: 10.1016/j.ultrasmedbio.2021.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 11/16/2021] [Accepted: 11/21/2021] [Indexed: 06/14/2023]
Abstract
Contrast-enhanced ultrasound imaging allows vascular imaging in a variety of diseases. Radial modulation imaging is a contrast agent-specific imaging approach for improving microbubble detection at high imaging frequencies (≥7.5 MHz), with imaging depth limited to a few centimeters. To provide high-sensitivity contrast-enhanced ultrasound imaging at high penetration depths, a new radial modulation imaging strategy using a very low frequency (100 kHz) ultrasound modulation wave in combination with imaging pulses ≤5 MHz is proposed. Microbubbles driven at 100 kHz were imaged in 10 successive oscillation states by manipulating the pulse repetition frequency to unlock the frame rate from the number of oscillation states. Tissue background was suppressed using frequency domain radial modulation imaging (F-RMI) and singular value decomposition-based radial modulation imaging (S-RMI). One hundred-kilohertz modulation resulted in significantly higher microbubble signal magnitude (63-88 dB) at the modulation frequency relative to that without 100-kHz modulation (51-59 dB). F-RMI produced images with high contrast-to-tissue ratios (CTRs) of 15 to 22 dB in a stationary tissue phantom, while S-RMI further improved the CTR (19-26 dB). These CTR values were significantly higher than that of amplitude modulation pulse inversion images (11.9 dB). In the presence of tissue motion (1 and 10 mm/s), S-RMI produced high-contrast images with CTR up to 18 dB; however, F-RMI resulted in minimal contrast enhancement in the presence of tissue motion. Finally, in transcranial ultrasound imaging studies through a highly attenuating ex vivo cranial bone, CTR values with S-RMI were as high as 23 dB. The proposed technique demonstrates successful modulation of microbubble response at 100 kHz for the first time. The presented S-RMI low-frequency radial modulation imaging strategy represents the first demonstration of real-time (20 frames/s), high-penetration-depth radial modulation imaging for contrast-enhanced ultrasound imaging.
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Affiliation(s)
- Bowen Jing
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Brooks D Lindsey
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA; School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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5
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Pellow C, Tan J, Chérin E, Demore CEM, Zheng G, Goertz DE. High frequency ultrasound nonlinear scattering from porphyrin nanobubbles. ULTRASONICS 2021; 110:106245. [PMID: 32932144 DOI: 10.1016/j.ultras.2020.106245] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/14/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
Emerging contrast imaging studies have highlighted the potential of nanobubbles for both intravascular and extravascular applications. Reports to date on nanobubbles have generally utilized low frequencies (<12 MHz), high concentrations (>109 mL-1), and B-mode or contrast-mode on preclinical and clinical systems. However, none of these studies directly examined nanobubble acoustic signatures systematically to implement nonlinear imaging schemes in a methodical manner based on nanobubble behaviour. Here, nanobubble nonlinear behaviour is investigated at high frequencies (12.5, 25, 30 MHz) and low concentration (106 mL-1) in a channel phantom, with different pulse types in single- and multi-pulse sequences to examine behaviour under conditions relevant to high frequency imaging. Porphyrin nanobubbles are demonstrated to initiate nonlinear scattering at high frequencies in a pressure-threshold dependent manner, as previously observed at low frequencies. This threshold behaviour was then utilized to demonstrate enhanced nanobubble imaging with pulse inversion, amplitude modulation, and a combination of the two, progressing towards the improved sensitivity and expanded utility of these ultrasound contrast agents.
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Affiliation(s)
- Carly Pellow
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Research Centre, 101 College St., Toronto, ON M5G 0A3, Canada; Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada.
| | - Josephine Tan
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Emmanuel Chérin
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Christine E M Demore
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Gang Zheng
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Research Centre, 101 College St., Toronto, ON M5G 0A3, Canada
| | - David E Goertz
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
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6
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Omoteso KA, Roy-Layinde TO, Laoye JA, Vincent UE, McClintock PVE. Acoustic vibrational resonance in a Rayleigh-Plesset bubble oscillator. ULTRASONICS SONOCHEMISTRY 2021; 70:105346. [PMID: 33011444 PMCID: PMC7786605 DOI: 10.1016/j.ultsonch.2020.105346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 08/06/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
The phenomenon of vibrational resonance (VR) has been investigated in a Rayleigh-Plesset oscillator for a gas bubble oscillating in an incompressible liquid while driven by a dual-frequency force consisting of high-frequency, amplitude-modulated, weak, acoustic waves. The complex equation of the Rayleigh-Plesset bubble oscillator model was expressed as the dynamics of a classical particle in a potential well of the Liénard type, thus allowing us to use both numerical and analytic approaches to investigate the occurrence of VR. We provide clear evidence that an acoustically-driven bubble oscillates in a time-dependent single or double-well potential whose properties are determined by the density of the liquid and its surface tension. We show both theoretically and numerically that, besides the VR effect facilitated by the variation of the parameters on which the high-frequency depends, amplitude modulation, the properties of the liquid in which the gas bubble oscillates contribute significantly to the occurrence of VR. In addition, we discuss the observation of multiple resonances and their origin for the double-well case, as well as their connection to the low frequency, weak, acoustic force field.
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Affiliation(s)
- K A Omoteso
- Department of Physics, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria
| | - T O Roy-Layinde
- Department of Physics, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria
| | - J A Laoye
- Department of Physics, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria
| | - U E Vincent
- Department of Physical Sciences, Redeemer's University, P.M.B. 230, Ede, Nigeria; Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom.
| | - P V E McClintock
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
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7
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Al-Jawadi S, Thakur SS. Ultrasound-responsive lipid microbubbles for drug delivery: A review of preparation techniques to optimise formulation size, stability and drug loading. Int J Pharm 2020; 585:119559. [PMID: 32574685 DOI: 10.1016/j.ijpharm.2020.119559] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 02/08/2023]
Abstract
Lipid-shelled microbubbles have received extensive interest to enhance ultrasound-responsive drug delivery outcomes due to their high biocompatibility. While therapeutic effectiveness of microbubbles is well established, there remain limitations in sample homogeneity, stability profile and drug loading properties which restrict these formulations from seeing widespread use in the clinical setting. In this review, we evaluate and discuss the most encouraging leads in lipid microbubble design and optimisation. We examine current applications in drug delivery for the systems and subsequently detail shell compositions and preparation strategies that improve monodispersity while retaining ultrasound responsiveness. We review how excipients and storage techniques help maximise stability and introduce different characterisation and drug loading techniques and evaluate their impact on formulation performance. The review concludes with current quality control measures in place to ensure lipid microbubbles can be reproducibly used in drug delivery.
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Affiliation(s)
- Sana Al-Jawadi
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Sachin S Thakur
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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8
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Helfield B. A Review of Phospholipid Encapsulated Ultrasound Contrast Agent Microbubble Physics. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:282-300. [PMID: 30413335 DOI: 10.1016/j.ultrasmedbio.2018.09.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/11/2018] [Accepted: 09/20/2018] [Indexed: 06/08/2023]
Abstract
Ultrasound contrast agent microbubbles have expanded the utility of biomedical ultrasound from anatomic imaging to the assessment of microvascular blood flow characteristics and ultrasound-assisted therapeutic applications. Central to their effectiveness in these applications is their resonant and non-linear oscillation behaviour. This article reviews the salient physics of an oscillating microbubble in an ultrasound field, with particular emphasis on phospholipid-coated agents. Both the theoretical underpinnings of bubble vibration and the experimental evidence of non-linear encapsulated bubble dynamics and scattering are discussed and placed within the context of current and emerging applications.
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Affiliation(s)
- Brandon Helfield
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
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Kooiman K, van Rooij T, Qin B, Mastik F, Vos HJ, Versluis M, Klibanov AL, de Jong N, Villanueva FS, Chen X. Focal areas of increased lipid concentration on the coating of microbubbles during short tone-burst ultrasound insonification. PLoS One 2017; 12:e0180747. [PMID: 28686673 PMCID: PMC5501608 DOI: 10.1371/journal.pone.0180747] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/20/2017] [Indexed: 01/13/2023] Open
Abstract
Acoustic behavior of lipid-coated microbubbles has been widely studied, which has led to several numerical microbubble dynamics models that incorporate lipid coating behavior, such as buckling and rupture. In this study we investigated the relationship between microbubble acoustic and lipid coating behavior on a nanosecond scale by using fluorescently labeled lipids. It is hypothesized that a local increased concentration of lipids, appearing as a focal area of increased fluorescence intensity (hot spot) in the fluorescence image, is related to buckling and folding of the lipid layer thereby highly influencing the microbubble acoustic behavior. To test this hypothesis, the lipid microbubble coating was fluorescently labeled. The vibration of the microbubble (n = 177; 2.3–10.3 μm in diameter) upon insonification at an ultrasound frequency of 0.5 or 1 MHz at 25 or 50 kPa acoustic pressure was recorded with the UPMC Cam, an ultra-high-speed fluorescence camera, operated at ~4–5 million frames per second. During short tone-burst excitation, hot spots on the microbubble coating occurred at relative vibration amplitudes > 0.3 irrespective of frequency and acoustic pressure. Around resonance, the majority of the microbubbles formed hot spots. When the microbubble also deflated acoustically, hot spot formation was likely irreversible. Although compression-only behavior (defined as substantially more microbubble compression than expansion) and subharmonic responses were observed in those microbubbles that formed hot spots, both phenomena were also found in microbubbles that did not form hot spots during insonification. In conclusion, this study reveals hot spot formation of the lipid monolayer in the microbubble’s compression phase. However, our experimental results show that there is no direct relationship between hot spot formation of the lipid coating and microbubble acoustic behaviors such as compression-only and the generation of a subharmonic response. Hence, our hypothesis that hot spots are related to acoustic buckling could not be verified.
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Affiliation(s)
- Klazina Kooiman
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
- Netherlands Heart Institute, Utrecht, the Netherlands
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
- * E-mail:
| | - Tom van Rooij
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
| | - Bin Qin
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Frits Mastik
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
| | - Hendrik J. Vos
- 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
| | - Michel Versluis
- Physics of Fluids Group, MIRA Institute for Biomedical Technology and Technical Medicine and MESA+ Institute for Nanotechnology, University of Twente, Enschede, the Netherlands
| | - Alexander L. Klibanov
- Cardiovascular Division, Department of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - 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
| | - Flordeliza S. Villanueva
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Xucai Chen
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
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Zhang Y, Zhang Y, Li S. Combination and simultaneous resonances of gas bubbles oscillating in liquids under dual-frequency acoustic excitation. ULTRASONICS SONOCHEMISTRY 2017; 35:431-439. [PMID: 27818004 DOI: 10.1016/j.ultsonch.2016.10.022] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 09/14/2016] [Accepted: 10/21/2016] [Indexed: 05/25/2023]
Abstract
The multi-frequency acoustic excitation has been employed to enhance the effects of oscillating bubbles in sonochemistry for many years. In the present paper, nonlinear dynamic oscillations of bubble under dual-frequency acoustic excitation are numerically investigated within a broad range of parameters. By investigating the power spectra and the response curves of oscillating bubbles, two unique features of bubble oscillations under dual-frequency excitation (termed as "combination resonance" and "simultaneous resonance") are revealed and discussed. Specifically, the amplitudes of the combination resonances are quantitatively compared with those of other traditional resonances (e.g. main resonances, harmonics). The influences of several paramount parameters (e.g., the bubble radius, the acoustic pressure amplitude, the energy allocation between two component waves) on nonlinear bubble oscillations are demonstrated.
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Affiliation(s)
- Yuning Zhang
- College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing, Beijing 102249, China; School of Engineering, University of Warwick, Coventry CV4 7AL, UK
| | - Yuning Zhang
- Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, Ministry of Education, North China Electric Power University, Beijing 102206, China; School of Power, Energy and Mechanical Engineering, North China Electric Power University, Beijing 102206, China.
| | - Shengcai Li
- School of Engineering, University of Warwick, Coventry CV4 7AL, UK
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11
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Mulvana H, Browning RJ, Luan Y, de Jong N, Tang MX, Eckersley RJ, Stride E. Characterization of Contrast Agent Microbubbles for Ultrasound Imaging and Therapy Research. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:232-251. [PMID: 27810805 DOI: 10.1109/tuffc.2016.2613991] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The high efficiency with which gas microbubbles can scatter ultrasound compared with the surrounding blood pool or tissues has led to their widespread employment as contrast agents in ultrasound imaging. In recent years, their applications have been extended to include super-resolution imaging and the stimulation of localized bio-effects for therapy. The growing exploitation of contrast agents in ultrasound and in particular these recent developments have amplified the need to characterize and fully understand microbubble behavior. The aim in doing so is to more fully exploit their utility for both diagnostic imaging and potential future therapeutic applications. This paper presents the key characteristics of microbubbles that determine their efficacy in diagnostic and therapeutic applications and the corresponding techniques for their measurement. In each case, we have presented information regarding the methods available and their respective strengths and limitations, with the aim of presenting information relevant to the selection of appropriate characterization methods. First, we examine methods for determining the physical properties of microbubble suspensions and then techniques for acoustic characterization of both suspensions and single microbubbles. The next section covers characterization of microbubbles as therapeutic agents, including as drug carriers for which detailed understanding of their surface characteristics and drug loading capacity is required. Finally, we discuss the attempts that have been made to allow comparison across the methods employed by various groups to characterize and describe their microbubble suspensions and promote wider discussion and comparison of microbubble behavior.
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12
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Harfield C, Fury CR, Memoli G, Jones P, Ovenden N, Stride E. Analysis of the Uncertainty in Microbubble Characterization. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1412-8. [PMID: 26993799 DOI: 10.1016/j.ultrasmedbio.2016.01.005] [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: 08/17/2015] [Revised: 12/22/2015] [Accepted: 01/11/2016] [Indexed: 05/23/2023]
Abstract
There is increasing interest in the use of microbubble contrast agents for quantitative imaging applications such as perfusion and blood pressure measurement. The response of a microbubble to ultrasound excitation is, however, extremely sensitive to its size, the properties of its coating and the characteristics of the sound field and surrounding environment. Hence the results of microbubble characterization experiments can be significantly affected by experimental uncertainties, and this can limit their utility in predictive modelling. The aim of this study was to attempt to quantify these uncertainties and their influence upon measured microbubble characteristics. Estimates for the parameters characterizing the microbubble coating were obtained by fitting model data to numerical simulations of microbubble dynamics. The effect of uncertainty in different experimental parameters was gauged by modifying the relevant input values to the fitting process. The results indicate that even the minimum expected uncertainty in, for example, measurements of microbubble radius using conventional optical microscopy, leads to variations in the estimated coating parameters of ∼20%. This should be taken into account in designing microbubble characterization experiments and in the use of data obtained from them.
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Affiliation(s)
- Caroline Harfield
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, UK
| | - Christopher R Fury
- Acoustics Group, National Physical Laboratory, Teddington, UK; Department of Physics and Astronomy, University College London, London, UK
| | - Gianluca Memoli
- Acoustics Group, National Physical Laboratory, Teddington, UK
| | - Philip Jones
- Department of Physics and Astronomy, University College London, London, UK
| | - Nick Ovenden
- Department of Mathematics, University College London, London, UK
| | - Eleanor Stride
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, UK.
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Fouan D, Achaoui Y, Payan C, Mensah S. Microbubble dynamics monitoring using a dual modulation method. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 137:EL144-EL150. [PMID: 25698042 DOI: 10.1121/1.4905883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
An experimental method for characterizing microbubbles' oscillations is presented. With a Dual Frequency ultrasound excitation method, both relative and absolute microbubble size variations can be measured. Using the same experimental setup, a simple signal processing step applied to both the amplitude and the frequency modulations yields a two-fold picture of microbubbles' dynamics. In addition, assuming the occurrence of small radial oscillations, the equilibrium radius of the microbubbles can be accurately estimated.
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Affiliation(s)
- Damien Fouan
- BF SYSTEMES, Technopôle de la Mer, 229, chemin de la Farlède, 83500 La Seyne-sur-Mer, France
| | - Younes Achaoui
- Laboratoire de Mécanique et d'Acoustique, Université d'Aix-Marseille, CNRS, 31 chemin Joseph Aiguier, 13420 Marseille, France , ,
| | - Cédric Payan
- Laboratoire de Mécanique et d'Acoustique, Université d'Aix-Marseille, CNRS, 31 chemin Joseph Aiguier, 13420 Marseille, France , ,
| | - Serge Mensah
- Laboratoire de Mécanique et d'Acoustique, Université d'Aix-Marseille, CNRS, 31 chemin Joseph Aiguier, 13420 Marseille, France , ,
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Rademeyer P, Carugo D, Lee JY, Stride E. Microfluidic system for high throughput characterisation of echogenic particles. LAB ON A CHIP 2015; 15:417-428. [PMID: 25367757 DOI: 10.1039/c4lc01206b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Echogenic particles, such as microbubbles and volatile liquid micro/nano droplets, have shown considerable potential in a variety of clinical diagnostic and therapeutic applications. The accurate prediction of their response to ultrasound excitation is however extremely challenging, and this has hindered the optimisation of techniques such as quantitative ultrasound imaging and targeted drug delivery. Existing characterisation techniques, such as ultra-high speed microscopy provide important insights, but suffer from a number of limitations; most significantly difficulty in obtaining large data sets suitable for statistical analysis and the need to physically constrain the particles, thereby altering their dynamics. Here a microfluidic system is presented that overcomes these challenges to enable the measurement of single echogenic particle response to ultrasound excitation. A co-axial flow focusing device is used to direct a continuous stream of unconstrained particles through the combined focal region of an ultrasound transducer and a laser. Both the optical and acoustic scatter from individual particles are then simultaneously recorded. Calibration of the device and example results for different types of echogenic particle are presented, demonstrating a high throughput of up to 20 particles per second and the ability to resolve changes in particle radius down to 0.1 μm with an uncertainty of less than 3%.
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Affiliation(s)
- Paul Rademeyer
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK.
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