1
|
Shakya G, Cattaneo M, Guerriero G, Prasanna A, Fiorini S, Supponen O. Ultrasound-responsive microbubbles and nanodroplets: A pathway to targeted drug delivery. Adv Drug Deliv Rev 2024; 206:115178. [PMID: 38199257 DOI: 10.1016/j.addr.2023.115178] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/21/2023] [Accepted: 12/31/2023] [Indexed: 01/12/2024]
Abstract
Ultrasound-responsive agents have shown great potential as targeted drug delivery agents, effectively augmenting cell permeability and facilitating drug absorption. This review focuses on two specific agents, microbubbles and nanodroplets, and provides a sequential overview of their drug delivery process. Particular emphasis is given to the mechanical response of the agents under ultrasound, and the subsequent physical and biological effects on the cells. Finally, the state-of-the-art in their pre-clinical and clinical implementation are discussed. Throughout the review, major challenges that need to be overcome in order to accelerate their clinical translation are highlighted.
Collapse
Affiliation(s)
- Gazendra Shakya
- Institute of Fluid Dynamics, D-MAVT, Sonneggstrasse 3, ETH Zurich, Zurich, 8092, Switzerland
| | - Marco Cattaneo
- Institute of Fluid Dynamics, D-MAVT, Sonneggstrasse 3, ETH Zurich, Zurich, 8092, Switzerland
| | - Giulia Guerriero
- Institute of Fluid Dynamics, D-MAVT, Sonneggstrasse 3, ETH Zurich, Zurich, 8092, Switzerland
| | - Anunay Prasanna
- Institute of Fluid Dynamics, D-MAVT, Sonneggstrasse 3, ETH Zurich, Zurich, 8092, Switzerland
| | - Samuele Fiorini
- Institute of Fluid Dynamics, D-MAVT, Sonneggstrasse 3, ETH Zurich, Zurich, 8092, Switzerland
| | - Outi Supponen
- Institute of Fluid Dynamics, D-MAVT, Sonneggstrasse 3, ETH Zurich, Zurich, 8092, Switzerland.
| |
Collapse
|
2
|
Su H, Sun J, Wang C, Wang H. Temperature impacts on the growth of hydrogen bubbles during ultrasonic vibration-enhanced hydrogen generation. ULTRASONICS SONOCHEMISTRY 2024; 102:106734. [PMID: 38128391 PMCID: PMC10772823 DOI: 10.1016/j.ultsonch.2023.106734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/08/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
To improve the hydrogen precipitation performance on the surface of the catalytic layer of the proton exchange membrane (PEM) hydrogen cathode, ultrasonic vibration was employed to accelerate the detachment of hydrogen bubbles on the surface of the catalytic layer. Based on the energy and mechanical analyses of nano and microbubbles, the hydrogen bubble generation mechanism and the effect of temperature on bubble parameters during the evolution process when the ultrasonic field is coupled with the electric field are investigated. The nucleation frequency of the hydrogen bubbles, the relationship between the pressure and temperature and the operating temperature during the generation and detachment of bubbles as well as the detachment radius of bubbles under the action of the ultrasonic field are obtained. The effects of ultrasound and temperature on hydrogen production were verified by visual experiments. The results show that the operating temperature affects the nucleation, growth, and detachment processes of hydrogen bubbles. The effect of temperature on the nucleation frequency of bubbles mainly comes from the Gibbs free energy required for the electrolysis reaction. The bubble radius and growth rate are both related to the temperature to the power of one-third. Ultrasonic waves enhance the separation of hydrogen bubbles from the catalyst surface by acoustic cavitation and impact effects. An increase in the working temperature reduces the activation energy barriers to be overcome for the electrolysis reaction of water, which together with a decrease in the Gibbs free energy and the surface tension coefficient, leads to an increase in the nucleation frequency of the catalytic layer and a decrease in the radius of bubble detachment, and thus improves the hydrogen precipitation performance. Visualization experiments show that in actual PEM hydrogen production, ultrasonic intensification can promote the formation of nucleation sites. The ultrasonic induced fine bubble flow not only has a drag effect on the bubble, but also intensifies the polymerization growth of the bubble due to the impact of the fine bubble flow, thus speeding up the detachment of the bubble, shortening the covering time of the hydrogen bubble on the surface of the catalytic electrode, reducing the activation voltage loss and improve the hydrogen production efficiency of PEM. The experimental results show that when the electrolyte is 60°C, the maximum hydrogen production efficiency of ultrasound is increased by 7.34%, and the average hydrogen production efficiency is increased by 5.83%.
Collapse
Affiliation(s)
- Hongqian Su
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China; Building Environment and Energy Power Engineering Experimental Center, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Jindong Sun
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China; Building Environment and Energy Power Engineering Experimental Center, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
| | - Caizhu Wang
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China; Building Environment and Energy Power Engineering Experimental Center, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Haofeng Wang
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China; Building Environment and Energy Power Engineering Experimental Center, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| |
Collapse
|
3
|
Feng K, Li X, Huang A, Wan M, Zong Y. Effect of tissue viscoelasticity and adjacent phase-changed microbubbles on vaporization process and direct growth threshold of nanodroplet in an ultrasonic field. ULTRASONICS SONOCHEMISTRY 2023; 101:106665. [PMID: 37922720 PMCID: PMC10643523 DOI: 10.1016/j.ultsonch.2023.106665] [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: 09/04/2023] [Revised: 10/13/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023]
Abstract
Understanding the behavior of nanodroplets converted into microbubbles with applied ultrasound is an important problem in tumor therapeutical and diagnostic applications. In this study, a comprehensive model is proposed to investigate the vaporization process and the direct growth threshold of the nanodroplet by following the vapor bubble growth, especially attention devoted to the effect of tissue viscoelasticity and adjacent phase-changed microbubbles (PCMBs). It is shown that the ultrasonic energy must be sufficiently strong to counterbalance the natural condensation of the vapor bubble and the tissue stiffness-inhibitory effect. The softer tissue with a lower shear modulus favors the vaporization process, and the nanodroplet has a lower direct growth threshold in the softer tissue. Moreover, the adjacent PCMBs show a suppression effect on the vaporization process due to the negative value of the secondary Bjerknes force, implying an attractive force, preventing the nanodroplet from escaping from the constraint of the adjacent PCMBs. However, according to the linear scattering theory, the attractive force signifies that the constraint is weak, causing the direct growth threshold to increase in the range of 0.09-0.24 MPa. The weak increase in threshold demonstrates that the direct growth threshold is relatively unaffected by the adjacent PCMBs. The prediction results of our model are in good agreement with the experiment results obtained by the echo enhancement method, in which the threshold is relatively independent of the intermediate concentration. The findings presented here provide physical insight that will be further helpful in understanding the complex behavior of the nanodroplet responses to ultrasound in practical medical applications.
Collapse
Affiliation(s)
- Kangyi Feng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Xinyue Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Anqi Huang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| |
Collapse
|
4
|
Aliabouzar M, Abeid BA, Kripfgans OD, Fowlkes JB, Estrada JB, Fabiilli ML. Real-time spatiotemporal characterization of mechanics and sonoporation of acoustic droplet vaporization in acoustically responsive scaffolds. APPLIED PHYSICS LETTERS 2023; 123:114101. [PMID: 37705893 PMCID: PMC10497320 DOI: 10.1063/5.0159661] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/26/2023] [Indexed: 09/15/2023]
Abstract
Phase-shift droplets provide a flexible and dynamic platform for therapeutic and diagnostic applications of ultrasound. The spatiotemporal response of phase-shift droplets to focused ultrasound, via the mechanism termed acoustic droplet vaporization (ADV), can generate a range of bioeffects. Although ADV has been used widely in theranostic applications, ADV-induced bioeffects are understudied. Here, we integrated ultra-high-speed microscopy, confocal microscopy, and focused ultrasound for real-time visualization of ADV-induced mechanics and sonoporation in fibrin-based, tissue-mimicking hydrogels. Three monodispersed phase-shift droplets-containing perfluoropentane (PFP), perfluorohexane (PFH), or perfluorooctane (PFO)-with an average radius of ∼6 μm were studied. Fibroblasts and tracer particles, co-encapsulated within the hydrogel, were used to quantify sonoporation and mechanics resulting from ADV, respectively. The maximum radial expansion, expansion velocity, induced strain, and displacement of tracer particles were significantly higher in fibrin gels containing PFP droplets compared to PFH or PFO. Additionally, cell membrane permeabilization significantly depended on the distance between the droplet and cell (d), decreasing rapidly with increasing d. Significant membrane permeabilization occurred when d was smaller than the maximum radius of expansion. Both ultra-high-speed and confocal images indicate a hyper-local region of influence by an ADV bubble, which correlated inversely with the bulk boiling point of the phase-shift droplets. The findings provide insight into developing optimal approaches for therapeutic applications of ADV.
Collapse
Affiliation(s)
| | - Bachir A. Abeid
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | | | | - Jonathan B. Estrada
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | |
Collapse
|
5
|
Aliabouzar M, Kripfgans OD, Brian Fowlkes J, Fabiilli ML. Bubble nucleation and dynamics in acoustic droplet vaporization: a review of concepts, applications, and new directions. Z Med Phys 2023; 33:387-406. [PMID: 36775778 PMCID: PMC10517405 DOI: 10.1016/j.zemedi.2023.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 12/30/2022] [Accepted: 01/09/2023] [Indexed: 02/12/2023]
Abstract
The development of phase-shift droplets has broadened the scope of ultrasound-based biomedical applications. When subjected to sufficient acoustic pressures, the perfluorocarbon phase in phase-shift droplets undergoes a phase-transition to a gaseous state. This phenomenon, termed acoustic droplet vaporization (ADV), has been the subject of substantial research over the last two decades with great progress made in design of phase-shift droplets, fundamental physics of bubble nucleation and dynamics, and applications. Here, we review experimental approaches, carried out via high-speed microscopy, as well as theoretical models that have been proposed to study the fundamental physics of ADV including vapor nucleation and ADV-induced bubble dynamics. In addition, we highlight new developments of ADV in tissue regeneration, which is a relatively recently exploited application. We conclude this review with future opportunities of ADV for advanced applications such as in situ microrheology and pressure estimation.
Collapse
Affiliation(s)
- Mitra Aliabouzar
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - Oliver D Kripfgans
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
6
|
Aliabouzar M, Kripfgans OD, Estrada JB, Brian Fowlkes J, Fabiilli ML. Multi-time scale characterization of acoustic droplet vaporization and payload release of phase-shift emulsions using high-speed microscopy. ULTRASONICS SONOCHEMISTRY 2022; 88:106090. [PMID: 35835060 PMCID: PMC9287562 DOI: 10.1016/j.ultsonch.2022.106090] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/27/2022] [Accepted: 07/04/2022] [Indexed: 05/16/2023]
Abstract
Acoustic droplet vaporization (ADV) is the phase-transitioning of perfluorocarbon emulsions, termed phase-shift emulsions, into bubbles using focused ultrasound. ADV has been utilized in many biomedical applications. For localized drug release, phase-shift emulsions with a bioactive payload can be incorporated within a hydrogel to yield an acoustically-responsive scaffold (ARS). The dynamics of ADV and associated drug release within hydrogels are not well understood. Additionally, emulsions used in ARSs often contain high molecular weight perfluorocarbons, which is unique relative to other ADV applications. In this study, we used ultra-high-speed brightfield and fluorescence microscopy, at frame rates up to 30 million and 0.5 million frames per second, respectively, to elucidate ADV dynamics and payload release kinetics in fibrin-based ARSs containing phase-shift emulsions with three different perfluorocarbons: perfluoropentane (PFP), perfluorohexane (PFH), and perfluorooctane (PFO). At an ultrasound excitation frequency of 2.5 MHz, the maximum expansion ratio, defined as the maximum bubble diameter during ADV normalized by the initial emulsion diameter, was 4.3 ± 0.8, 4.1 ± 0.6, and 3.6 ± 0.4, for PFP, PFH, PFO emulsions, respectively. ADV yielded stable bubble formation in PFP and PFH emulsions, though the bubble growth rate post-ADV was three orders of magnitudes slower in the latter emulsion. Comparatively, ADV generated bubbles in PFO emulsions underwent repeated vaporization/recondensation or fragmentation. Different ADV-generated bubble dynamics resulted in distinct release kinetics in phase-shift emulsions carrying fluorescently-labeled payloads. The results provide physical insight enabling the modulation of bubble dynamics with ADV and hence release kinetics, which can be used for both diagnostic and therapeutic applications of ultrasound.
Collapse
Affiliation(s)
- Mitra Aliabouzar
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA.
| | - Oliver D Kripfgans
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Jonathan B Estrada
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
7
|
Ghasemi M, Yu ACH, Sivaloganathan S. An enhanced, rational model to study acoustic vaporization dynamics of a bubble encapsulated within a nonlinearly elastic shell. ULTRASONICS SONOCHEMISTRY 2022; 83:105948. [PMID: 35151989 PMCID: PMC8841372 DOI: 10.1016/j.ultsonch.2022.105948] [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: 10/06/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 05/15/2023]
Abstract
Acoustic droplet vaporization (ADV) is a new approach to generate vapor bubbles that have potentially broad medical applications. ADV-generated bubbles can be used as contrast agents in acoustic imaging, as drug carriers to deliver drugs to particular targets, and also in embolotherapy, thermal therapy, and histotripsy. However, despite much progress, ADV dynamics have still not been well understood and properly modeled. In this paper, we present a theoretical study of ultrasound-induced evaporation of a droplet encapsulated by a shell. The main emphasis of this theoretical study is on a proper description of the supercritical state occurring after bubble collapse. For this purpose, an isentropic equation of state for a van der Waals gas is used to describe the bubble behavior in the supercritical state. Sensitivity of the vaporization process is investigated for different acoustic and geometrical parameters and mechanical properties of the shell. Results show that the value of the minimum pressure required for direct vaporization (without any oscillatory behavior) depends on shell elasticity and initial size of the droplet, especially at high frequencies (greater than 2[MHz]). Moreover, it has been shown that applying an acoustic wave with proper phase such that thermal equilibrium of the bubble temperature with the surrounding liquid is attained, results in direct vaporization at lower acoustic pressure.
Collapse
Affiliation(s)
- Maryam Ghasemi
- Dept. of Applied Mathematics, Univ. Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Alfred C H Yu
- Dept. of Electrical and Computer Engineering, Univ. Waterloo, Waterloo, ON N2L 3G1, Canada
| | | |
Collapse
|
8
|
Park S, Son G. Numerical investigation of acoustic vaporization threshold of microdroplets. ULTRASONICS SONOCHEMISTRY 2021; 71:105361. [PMID: 33160151 PMCID: PMC7786634 DOI: 10.1016/j.ultsonch.2020.105361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/19/2020] [Accepted: 10/07/2020] [Indexed: 05/18/2023]
Abstract
A numerical model is presented for the acoustic vaporization threshold of a dodecafluoropentane (or perfluoropentane) microdroplet. The model is based on the Rayleigh-Plesset equation and is improved by properly treating the supercritical state that occurs when a bubble collapses rapidly and by employing the van der Waals equation of state to consider the supercritical state. The present computations demonstrate that the microdroplet vaporization behavior depends intricately on bubble compressibility, liquid inertia and phase-change heat transfer under acoustic excitation conditions. We present acoustic pressure-frequency diagrams for bubble growth regimes and the ADV threshold conditions. The effects of acoustic parameters, fluid properties and the droplet radius on the ADV threshold are investigated.
Collapse
Affiliation(s)
- Sukwon Park
- Department of Mechanical Engineering, Sogang University, Seoul, South Korea
| | - Gihun Son
- Department of Mechanical Engineering, Sogang University, Seoul, South Korea.
| |
Collapse
|
9
|
Lajoinie G, Segers T, Versluis M. High-Frequency Acoustic Droplet Vaporization is Initiated by Resonance. PHYSICAL REVIEW LETTERS 2021; 126:034501. [PMID: 33543968 DOI: 10.1103/physrevlett.126.034501] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/02/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
Vaporization of low-boiling point droplets has numerous applications in combustion, process engineering, and in recent years, in clinical medicine. However, the physical mechanisms governing the phase conversion are only partly explained. Here, we show that an acoustic resonance can arise from the large speed of sound mismatch between a perfluorocarbon microdroplet and its surroundings. The fundamental resonance mode obeys a unique relationship kR∼0.65 between droplet size and driving frequency that leads to a threefold pressure amplification inside the droplet. Classical nucleation theory shows that this pressure amplification increases the nucleation rate by several orders of magnitude. These findings are confirmed by high-speed imaging performed at a timescale of 10 ns. The optical recordings demonstrate that droplets exposed to intense acoustic waves generated by interdigital transducers nucleate only if they match the theoretical resonance size.
Collapse
Affiliation(s)
- Guillaume Lajoinie
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
| | - Tim Segers
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
| | - Michel Versluis
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
| |
Collapse
|
10
|
Stricker L, Guido I, Breithaupt T, Mazza MG, Vollmer J. Hybrid sideways/longitudinal swimming in the monoflagellate Shewanella oneidensis: from aerotactic band to biofilm. J R Soc Interface 2020; 17:20200559. [PMID: 33109020 PMCID: PMC7653395 DOI: 10.1098/rsif.2020.0559] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/06/2020] [Indexed: 11/12/2022] Open
Abstract
Shewanella oneidensis MR-1 are facultative aerobic electroactive bacteria with an appealing potential for sustainable energy production and bioremediation. They gather around air sources, forming aerotactic bands and biofilms. Here, we experimentally follow the evolution of the band around an air bubble, and we find good agreement with the numerical solutions of the pertinent transport equations. Video microscopy reveals a transition between motile and non-motile MR-1 upon oxygen depletion, preventing further development of the biofilm. We discover that MR-1 can alternate between longitudinal fast and sideways slow swimming. The resulting bimodal velocity distributions change in response to different oxygen concentrations and gradients, supporting the biological functions of aerotaxis and confinement.
Collapse
Affiliation(s)
- Laura Stricker
- ETH Zürich, Department of Materials, Polymer Physics, 8093 Zurich, Switzerland
| | - Isabella Guido
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany
| | - Thomas Breithaupt
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany
| | - Marco G. Mazza
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany
- Loughborough University, Interdisciplinary Centre for Mathematical Modelling and Department of Mathematical Sciences, Loughborough, Leicestershire LE11 3TU, UK
| | - Jürgen Vollmer
- University of Leipzig, Institute of Theoretical Physics, 04103 Leipzig, Germany
| |
Collapse
|
11
|
Versluis M, Stride E, Lajoinie G, Dollet B, Segers T. Ultrasound Contrast Agent Modeling: A Review. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2117-2144. [PMID: 32546411 DOI: 10.1016/j.ultrasmedbio.2020.04.014] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 05/21/2023]
Abstract
Ultrasound is extensively used in medical imaging, being safe and inexpensive and operating in real time. Its scope of applications has been widely broadened by the use of ultrasound contrast agents (UCAs) in the form of microscopic bubbles coated by a biocompatible shell. Their increased use has motivated a large amount of research to understand and characterize their physical properties as well as their interaction with the ultrasound field and their surrounding environment. Here we review the theoretical models that have been proposed to study and predict the behavior of UCAs. We begin with a brief introduction on the development of UCAs. We then present the basics of free-gas-bubble dynamics upon which UCA modeling is based. We review extensively the linear and non-linear models for shell elasticity and viscosity and present models for non-spherical and asymmetric bubble oscillations, especially in the presence of surrounding walls or tissue. Then, higher-order effects such as microstreaming, shedding and acoustic radiation forces are considered. We conclude this review with promising directions for the modeling and development of novel agents.
Collapse
Affiliation(s)
- Michel Versluis
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, Enschede, the Netherlands.
| | - Eleanor Stride
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Guillaume Lajoinie
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, Enschede, the Netherlands
| | - Benjamin Dollet
- Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire de Physique (LIPhy), Université Grenoble Alpes, Grenoble, France
| | - Tim Segers
- Physics of Fluids Group, MESA+ Institute for Nanotechnology, Technical Medical (TechMed) Center, University of Twente, Enschede, the Netherlands
| |
Collapse
|
12
|
Xu T, Cui Z, Li D, Cao F, Xu J, Zong Y, Wang S, Bouakaz A, Wan M, Zhang S. Cavitation characteristics of flowing low and high boiling-point perfluorocarbon phase-shift nanodroplets during focused ultrasound exposures. ULTRASONICS SONOCHEMISTRY 2020; 65:105060. [PMID: 32199255 DOI: 10.1016/j.ultsonch.2020.105060] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 01/15/2020] [Accepted: 03/07/2020] [Indexed: 06/10/2023]
Abstract
This work investigated and compared the dynamic cavitation characteristics between low and high boiling-point phase-shift nanodroplets (NDs) under physiologically relevant flow conditions during focused ultrasound (FUS) exposures at different peak rarefactional pressures. A passive cavitation detection (PCD) system was used to monitor cavitation activity during FUS exposure at various acoustic pressure levels. Root mean square (RMS) amplitudes of broadband noise, spectrograms of the passive cavitation detection signals, and normalized inertial cavitation dose (ICD) values were calculated. Cavitation activity of low-boiling-point perfluoropentane (PFP) NDs and high boiling-point perfluorohexane (PFH) NDs flowing at in vitro mean velocities of 0-15 cm/s were compared in a 4-mm diameter wall-less vessel in a transparent tissue-mimicking phantom. In the static state, both types of phase-shift NDs exhibit a sharp rise in cavitation intensity during initial FUS exposure. Under flow conditions, cavitation activity of the PFH NDs reached the steady state less rapidly compared to PFP NDs under the lower acoustic pressure (1.35 MPa); at the higher acoustic pressure (1.65 MPa), the RMS amplitude increased more sharply during the initial FUS exposure period. In particular, the RMS-time curves of the PFP NDs shifted upward as the mean flow velocity increased from 0 to 15 cm/s; the RMS amplitude of the PFH ND solution increased from 0 to 10 cm/s and decreased at 15 cm/s. Moreover, amplitudes of the echo signal for the low boiling-point PFP NDs were higher compared to the high boiling-point PFH NDs in the lower frequency range, whereas the inverse occurred in the higher frequency range. Both PFP and PFH NDs showed increased cavitation activity in the higher frequency under the flow condition compared to the static state, especially PFH NDs. At 1.65 MPa, normalized ICD values for PFH increased from 0.93 ± 0.03 to 0.96 ± 0.04 and from 0 to 10 cm/s, then decreased to 0.86 ± 0.05 at 15 cm/s. This work contributes to our further understanding of cavitation characteristics of phase-shift NDs under physiologically relevant flow conditions during FUS exposure. In addition, the results provide a reference for selecting suitable phase-shift NDs to enhance the efficiency of cavitation-mediated ultrasonic applications.
Collapse
Affiliation(s)
- Tianqi Xu
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Zhiwei Cui
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Dapeng Li
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Fangyuan Cao
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Jichen Xu
- Institute of Artificial Intelligence and Robotics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China; National Engineering Laboratory for Visual Information Processing and Applications, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Supin Wang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | | | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| | - Siyuan Zhang
- The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| |
Collapse
|
13
|
Zhang S, Xu T, Cui Z, Shi W, Wu S, Zong Y, Niu G, He X, Wan M. Time and Frequency Characteristics of Cavitation Activity Enhanced by Flowing Phase-Shift Nanodroplets and Lipid-Shelled Microbubbles During Focused Ultrasound Exposures. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:2118-2132. [PMID: 31151732 DOI: 10.1016/j.ultrasmedbio.2019.04.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/02/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
This study investigated and compared the time and frequency characteristics of cavitation activity between phase-shift nanodroplets (NDs) and lipid-shelled microbubbles (MBs) exposed to focused ultrasound (FUS) under physiologically relevant flow conditions. Root-mean-square (RMS) of broadband noise, spectrograms of the passive cavitation detection signals and inertial cavitation doses (ICDs) were calculated during FUS at varying mean flow velocities and two different peak-rarefactional pressures. At a lower pressure of 0.94 MPa, the mean values of the RMS amplitudes versus time for the NDs showed an upward trend but slowed down as the mean flow velocity increased. For flowing NDs, the rate of growth in RMS amplitudes within 2-5 MHz decreased more obviously than those within 5-8 MHz. At a higher pressure of 1.07 MPa, the increase in RMS amplitudes was accelerated as the mean flow velocity increased from 0 to 10 cm/s and slowed down as the mean flow velocity reached 15 cm/s. The general downward trends of RMS amplitudes for the MBs were retarded as the mean flow velocity increased at both acoustic pressures of 0.94 MPa and 1.07 MPa. At 0.94 MPa, the mean ICD value for the NDs decreased from 57 to 36 as the mean flow velocity increased from 0 to 20 cm/s. At 1.07 MPa, the mean ICD value initially increased from 45 to 57 as the mean flow velocity increased from 0 to 10 cm/s and subsequently decreased to 43 as the mean flow velocity reached 20 cm/s. For the MBs, the mean ICD value increased with increasing mean flow velocity at both acoustic pressures. These results could aid in future investigations of cavitation-enhanced FUS with the flowing phase-shift NDs and encapsulated, gas-filled MBs for various applications.
Collapse
Affiliation(s)
- Siyuan Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Tianqi Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Zhiwei Cui
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Wen Shi
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Shan Wu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Gang Niu
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Xijing He
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, People's Republic of China
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
| |
Collapse
|
14
|
Applications of Ultrasound to Stimulate Therapeutic Revascularization. Int J Mol Sci 2019; 20:ijms20123081. [PMID: 31238531 PMCID: PMC6627741 DOI: 10.3390/ijms20123081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022] Open
Abstract
Many pathological conditions are characterized or caused by the presence of an insufficient or aberrant local vasculature. Thus, therapeutic approaches aimed at modulating the caliber and/or density of the vasculature by controlling angiogenesis and arteriogenesis have been under development for many years. As our understanding of the underlying cellular and molecular mechanisms of these vascular growth processes continues to grow, so too do the available targets for therapeutic intervention. Nonetheless, the tools needed to implement such therapies have often had inherent weaknesses (i.e., invasiveness, expense, poor targeting, and control) that preclude successful outcomes. Approximately 20 years ago, the potential for using ultrasound as a new tool for therapeutically manipulating angiogenesis and arteriogenesis began to emerge. Indeed, the ability of ultrasound, especially when used in combination with contrast agent microbubbles, to mechanically manipulate the microvasculature has opened several doors for exploration. In turn, multiple studies on the influence of ultrasound-mediated bioeffects on vascular growth and the use of ultrasound for the targeted stimulation of blood vessel growth via drug and gene delivery have been performed and published over the years. In this review article, we first discuss the basic principles of therapeutic ultrasound for stimulating angiogenesis and arteriogenesis. We then follow this with a comprehensive cataloging of studies that have used ultrasound for stimulating revascularization to date. Finally, we offer a brief perspective on the future of such approaches, in the context of both further research development and possible clinical translation.
Collapse
|
15
|
Koshkina O, Lajoinie G, Bombelli FB, Swider E, Cruz LJ, White PB, Schweins R, Dolen Y, van Dinther EAW, van Riessen NK, Rogers SE, Fokkink R, Voets IK, van Eck ERH, Heerschap A, Versluis M, de Korte CL, Figdor CG, de Vries IJM, Srinivas M. Multicore Liquid Perfluorocarbon-Loaded Multimodal Nanoparticles for Stable Ultrasound and 19F MRI Applied to In Vivo Cell Tracking. ADVANCED FUNCTIONAL MATERIALS 2019; 29:1806485. [PMID: 32132881 PMCID: PMC7056356 DOI: 10.1002/adfm.201806485] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Indexed: 05/22/2023]
Abstract
Ultrasound is the most commonly used clinical imaging modality. However, in applications requiring cell-labeling, the large size and short active lifetime of ultrasound contrast agents limit their longitudinal use. Here, 100 nm radius, clinically applicable, polymeric nanoparticles containing a liquid perfluorocarbon, which enhance ultrasound contrast during repeated ultrasound imaging over the course of at least 48 h, are described. The perfluorocarbon enables monitoring the nanoparticles with quantitative 19F magnetic resonance imaging, making these particles effective multimodal imaging agents. Unlike typical core-shell perfluorocarbon-based ultrasound contrast agents, these nanoparticles have an atypical fractal internal structure. The nonvaporizing highly hydrophobic perfluorocarbon forms multiple cores within the polymeric matrix and is, surprisingly, hydrated with water, as determined from small-angle neutron scattering and nuclear magnetic resonance spectroscopy. Finally, the nanoparticles are used to image therapeutic dendritic cells with ultrasound in vivo, as well as with 19F MRI and fluorescence imaging, demonstrating their potential for long-term in vivo multimodal imaging.
Collapse
Affiliation(s)
- Olga Koshkina
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands; Physical Chemistry of Polymers, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Guillaume Lajoinie
- Physics of Fluids Group, Technical Medical (TechMed) Centre and MESA+ Institute for, Nanotechnology, University of Twente, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands
| | - Francesca Baldelli Bombelli
- Laboratory of Supramolecular and BioNano Materials, (SupraBioNanoLab), Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta,", Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy
| | - Edyta Swider
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| | - Luis J Cruz
- Translational Nanobiomaterials and Imaging, Department of Radiology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Paul B White
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Ralf Schweins
- Institut Laue - Langevin, DS/LSS, 71 Avenue des Martyrs, CS 20 156, 38042 Grenoble CEDEX 9, France
| | - Yusuf Dolen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| | - Eric A W van Dinther
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| | - N Koen van Riessen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| | - Sarah E Rogers
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxford OX11 0QX, UK
| | - Remco Fokkink
- Department of Agrotechnology and Food Sciences, Physical Chemistry and Soft Matter, Wageningen University, 6708 WE, Wageningen, Netherlands
| | - Ilja K Voets
- Laboratory of Self-Organizing Soft Matter, Laboratory of Macromolecular and Organic Chemistry, Department of Chemical Engineering and Chemistry and Institute for Complex Molecular Systems, Eindhoven University of Technology, De Rondom 70, 5612 AP, Eindhoven, The Netherlands
| | - Ernst R H van Eck
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboudumc, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Michel Versluis
- Physics of Fluids Group, Technical Medical (TechMed) Centre and MESA+ Institute for, Nanotechnology, University of Twente, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands
| | - Chris L de Korte
- Physics of Fluids Group, Technical Medical (TechMed) Centre and MESA+ Institute for, Nanotechnology, University of Twente, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands; Department of Radiology and Nuclear Medicine, Radboudumc, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Carl G Figdor
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| | - I Jolanda M de Vries
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| | - Mangala Srinivas
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences (RIMLS), Geert Grooteplein Zuid 28, 6525 GA, Nijmegen, The Netherlands
| |
Collapse
|
16
|
Zilonova EM, Solovchuk M, Sheu TWH. Simulation of cavitation enhanced temperature elevation in a soft tissue during high-intensity focused ultrasound thermal therapy. ULTRASONICS SONOCHEMISTRY 2019; 53:11-24. [PMID: 30770275 DOI: 10.1016/j.ultsonch.2018.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 12/05/2018] [Accepted: 12/05/2018] [Indexed: 05/24/2023]
Abstract
The present study aims to investigate temperature distribution caused by bubble oscillations in a soft tissue during focused ultrasound therapy by introducing a coupled temperature-cavitation model. The proposed model is capable of describing bubble dynamics, viscoelastic properties of surrounding tissue-like medium, temperature distribution inside and outside the bubble, vapor diffusion within the bubble and vapor flux through the bubble wall to the exterior. The continuous temperature distribution inside and outside the oscillating bubble in soft tissue subject to ultrasound wave with high acoustic pressure is presented. The temperature close to the bubble wall can reach the value of about 103 K. The elasticity of soft tissue reduces temperature values. The relaxation time effect strongly depends on the period of the ultrasound wave. If the vapor mass flux effect is taken into account in the simulations, the rectified growth effect can be observed, which can lead to the decrease of the temperature values. Due to the growth of the bubble, the effects of elasticity and relaxation time on the temperature become less prominent during several bubble oscillation cycles. The impact of cavitation heat source terms on the exterior temperature was examined and led us to draw conclusion that, even though these heat sources can increase the outside temperature values, they can not be treated as main mechanisms for the temperature elevation during a few microseconds. The performed comparison with uncoupled conventional model for the outside temperature calculation revealed that coupling with inside temperature model delivers incomparably higher values to the bubble's exterior and, therefore, it is essential for the accurate description of the treatment process.
Collapse
Affiliation(s)
- E M Zilonova
- Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan, ROC.
| | - M Solovchuk
- Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan, ROC; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. 35, Keyan Road, Zhunan 35053, Taiwan, ROC.
| | - T W H Sheu
- Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan, ROC; Center of Advanced Study in Theoretical Science (CASTS), National Taiwan University, Taiwan, ROC; Department of Mathematics, National Taiwan University, Taiwan, ROC.
| |
Collapse
|
17
|
Zhang G, Lin S, Leow CH, Pang KT, Hernández-Gil J, Long NJ, Eckersley R, Matsunaga T, Tang MX. Quantification of Vaporised Targeted Nanodroplets Using High-Frame-Rate Ultrasound and Optics. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1131-1142. [PMID: 30827708 DOI: 10.1016/j.ultrasmedbio.2019.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/08/2019] [Accepted: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Molecular targeted nanodroplets that can extravasate beyond the vascular space have great potential to improve tumor detection and characterisation. High-frame-rate ultrasound, on the other hand, is an emerging tool for imaging at a frame rate one to two orders of magnitude higher than those of existing ultrasound systems. In this study, we used high-frame-rate ultrasound combined with optics to study the acoustic response and size distribution of folate receptor (FR)-targeted versus non-targeted (NT)-nanodroplets in vitro with MDA-MB-231 breast cancer cells immediately after ultrasound activation. A flow velocity mapping technique, Stokes' theory and optical microscopy were used to estimate the size of both floating and attached vaporised nanodroplets immediately after activation. The floating vaporised nanodroplets were on average more than seven times larger than vaporised nanodroplets attached to the cells. The results also indicated that the acoustic signal of vaporised FR-targeted-nanodroplets persisted after activation, with 70% of the acoustic signals still present 1 s after activation, compared with the vaporised NT-nanodroplets, for which only 40% of the acoustic signal remained. The optical microscopic images revealed on average six times more vaporised FR-targeted-nanodroplets generated with a wider range of diameters (from 4 to 68 µm) that were still attached to the cells, compared with vaporised NT-nanodroplets (from 1 to 7 µm) with non-specific binding after activation. The mean size of attached vaporised FR-targeted-nanodroplets was on average about threefold larger than that of attached vaporised NT-nanodroplets. Taking advantage of high-frame-rate contrast-enhanced ultrasound and optical microscopy, this study offers an improved understanding of the vaporisation of the targeted nanodroplets in terms of their size and acoustic response in comparison with NT-nanodroplets. Such understanding would help in the design of optimised methodology for imaging and therapeutic applications.
Collapse
Affiliation(s)
- Ge Zhang
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Shengtao Lin
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Chee Hao Leow
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Kuin Tian Pang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | | | - Nicholas J Long
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Robert Eckersley
- Division of Imaging Sciences & Biomedical Engineering Department, King's College London, United Kingdom
| | - Terry Matsunaga
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, United Kingdom.
| |
Collapse
|
18
|
Rojas JD, Borden MA, Dayton PA. Effect of Hydrostatic Pressure, Boundary Constraints and Viscosity on the Vaporization Threshold of Low-Boiling-Point Phase-Change Contrast Agents. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:968-979. [PMID: 30658858 DOI: 10.1016/j.ultrasmedbio.2018.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/04/2018] [Accepted: 11/11/2018] [Indexed: 05/09/2023]
Abstract
The vaporization of low-boiling-point phase-change contrast agents (PCCAs) using ultrasound has been explored in vitro and in vivo. However, it has been reported that the pressure required for activation is higher in vivo, even after attenuation is accounted for. In this study, the effect of boundary constraints, hydrostatic pressure and viscosity on PCCA vaporization pressure threshold are evaluated to explore possible mechanisms for variations in in vivo vaporization behavior. Vaporization was measured in microtubes of varying inner diameter and a pressurized chamber under different hydrostatic pressures using a range of ultrasound pressures. Furthermore, the activation threshold was evaluated in the kidneys of rats. The results confirm that the vaporization threshold is higher in vivo and reveal an increasing activation threshold inversely proportional to constraining tube size and inversely proportional to surrounding viscosity in constrained environments. Counterintuitively, increased hydrostatic pressure had no significant effect experimentally on the PCCA vaporization threshold, although it was confirmed that this result was supported by homogeneous nucleation theory for liquid perfluorocarbon vaporization. These factors suggest that constraints caused by the surrounding tissue and capillary walls, as well as increased viscosity in vivo, contribute to the increased vaporization threshold compared with in vitro experiments, although more work is required to confirm all relevant factors.
Collapse
Affiliation(s)
- Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Mark A Borden
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
| |
Collapse
|
19
|
Fan CH, Lin YT, Ho YJ, Yeh CK. Spatial-Temporal Cellular Bioeffects from Acoustic Droplet Vaporization. Theranostics 2018; 8:5731-5743. [PMID: 30555577 PMCID: PMC6276289 DOI: 10.7150/thno.28782] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/16/2018] [Indexed: 01/04/2023] Open
Abstract
One of the major challenges in developing acoustic droplet vaporization (ADV)-associated therapy as an effective and safe strategy is the precise determination of the spatial cellular bioeffects after ADV (cell death or cell membrane permeabilization). In this study, we combined high-speed camera imaging and live-cell microscopic imaging to observe the transient dynamics of droplets during ADV and to evaluate the mechanical force on cells. Methods: C6 glioma cells were co-incubated with DiI-labeled droplets (radius: 1.5, 2.25, and 3.0 μm). We used an acousto-optical system for high-speed bright-field (500 kfps) and fluorescence (40 kfps) microscopic imaging in order to visualize the dynamics of droplets under ultrasound excitation (frequency = 5 MHz, pressure = 5-8 MPa, cycle number = 3, pulse number = 1). Live-cell microscopic imaging was used to monitor the cell morphology, cell membrane permeabilization, and cell viability by membrane-anchored Lyn-yellow fluorescence protein, propidium Iodide staining, and calcein blue AM staining, respectively. Results: We discovered that the spatial distribution of ADV-induced bioeffects could be mapped to the physical dynamics of droplet vaporization. For droplets with a 1.5 μm radius, the distance threshold for ADV-induced cell death (5.5±1.9 μm) and reversible membrane permeabilization (11.3±3.5 μm) was well correlated with the distance of ADV-bubble pressing downward to the floor (5.7±1.3 μm) and maximum distance of droplet expansion (11.5±2.6 μm), respectively. These distances were enlarged by increasing the droplet sizes and insonation acoustic pressures. The live-cell imaging results show that ADV-bubbles can directly disrupt the cell membrane layer and induce intensive intracellular substance leakage. Further, the droplets shed the payload onto nearby cells during ADV, suggesting ADV could directly induce adjacent cell death by physical force and enhancement of chemotherapy to distant cells. Conclusion: This study provide new insights into the ADV-mediated physicochemical synergic effect for medical applications.
Collapse
|
20
|
Li J, Zhao F, Deng Y, Liu D, Chen CH, Shih WC. Photothermal generation of programmable microbubble array on nanoporous gold disks. OPTICS EXPRESS 2018; 26:16893-16902. [PMID: 30119508 DOI: 10.1364/oe.26.016893] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/04/2018] [Indexed: 05/25/2023]
Abstract
We present a novel technique to generate microbubbles photothermally by continuous-wave laser irradiation of nanoporous gold disk (NPGD) array covered microfluidic channels. When a single laser spot is focused on the NPGDs, a microbubble can be generated with controlled size by adjusting the laser power. The dynamics of both bubble growth and shrinkage are studied. Using computer-generated holography on a spatial light modulator (SLM), simultaneous generation of multiple microbubbles at arbitrary locations with independent control is demonstrated. A potential application of flow manipulation is demonstrated using a microfluidic X-shaped junction. The advantages of this technique are flexible bubble generation locations, long bubble lifetimes, no need for light-adsorbing dyes, high controllability over bubble size, and relatively lower power consumption.
Collapse
|
21
|
Lin S, Zhang G, Jamburidze A, Chee M, Leow CH, Garbin V, Tang MX. Imaging of vaporised sub-micron phase change contrast agents with high frame rate ultrasound and optics. Phys Med Biol 2018; 63:065002. [PMID: 29384498 DOI: 10.1088/1361-6560/aaac05] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Phase-change ultrasound contrast agent (PCCA), or nanodroplet, shows promise as an alternative to the conventional microbubble agent over a wide range of diagnostic applications. Meanwhile, high-frame-rate (HFR) ultrasound imaging with microbubbles enables unprecedented temporal resolution compared to traditional contrast-enhanced ultrasound imaging. The combination of HFR ultrasound imaging and PCCAs can offer the opportunity to observe and better understand PCCA behaviour after vaporisation captures the fast phenomenon at a high temporal resolution. In this study, we utilised HFR ultrasound at frame rates in the kilohertz range (5-20 kHz) to image native and size-selected PCCA populations immediately after vaporisation in vitro within clinical acoustic parameters. The size-selected PCCAs through filtration are shown to preserve a sub-micron-sized (mean diameter < 200 nm) population without micron-sized outliers (>1 µm) that originate from native PCCA emulsion. The results demonstrate imaging signals with different amplitudes and temporal features compared to that of microbubbles. Compared with the microbubbles, both the B-mode and pulse-inversion (PI) signals from the vaporised PCCA populations were reduced significantly in the first tens of milliseconds, while only the B-mode signals from the PCCAs were recovered during the next 400 ms, suggesting significant changes to the size distribution of the PCCAs after vaporisation. It is also shown that such recovery in signal over time is not evident when using size-selective PCCAs. Furthermore, it was found that signals from the vaporised PCCA populations are affected by the amplitude and frame rate of the HFR ultrasound imaging. Using high-speed optical camera observation (30 kHz), we observed a change in particle size in the vaporised PCCA populations exposed to the HFR ultrasound imaging pulses. These findings can further the understanding of PCCA behaviour under HFR ultrasound imaging.
Collapse
Affiliation(s)
- Shengtao Lin
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
22
|
Zullino S, Argenziano M, Stura I, Guiot C, Cavalli R. From Micro- to Nano-Multifunctional Theranostic Platform: Effective Ultrasound Imaging Is Not Just a Matter of Scale. Mol Imaging 2018; 17:1536012118778216. [PMID: 30213222 PMCID: PMC6144578 DOI: 10.1177/1536012118778216] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/20/2018] [Accepted: 04/08/2018] [Indexed: 12/20/2022] Open
Abstract
Ultrasound Contrast Agents (UCAs) consisting of gas-filled-coated Microbubbles (MBs) with diameters between 1 and 10 µm have been used for a number of decades in diagnostic imaging. In recent years, submicron contrast agents have proven to be a viable alternative to MBs for ultrasound (US)-based applications for their capability to extravasate and accumulate in the tumor tissue via the enhanced permeability and retention effect. After a short overview of the more recent approaches to ultrasound-mediated imaging and therapeutics at the nanoscale, phase-change contrast agents (PCCAs), which can be phase-transitioned into highly echogenic MBs by means of US, are here presented. The phenomenon of acoustic droplet vaporization (ADV) to produce bubbles is widely investigated for both imaging and therapeutic applications to develop promising theranostic platforms.
Collapse
Affiliation(s)
- Sara Zullino
- Department of Neuroscience, University of Turin, Turin, Italy
| | - Monica Argenziano
- Department of Drug Science and Technology, University of Turin, Turin, Italy
| | - Ilaria Stura
- Department of Clinical and Biological Science, University of Turin, Turin, Italy
| | - Caterina Guiot
- Department of Neuroscience, University of Turin, Turin, Italy
| | - Roberta Cavalli
- Department of Drug Science and Technology, University of Turin, Turin, Italy
| |
Collapse
|
23
|
Lacour T, Guédra M, Valier-Brasier T, Coulouvrat F. A model for acoustic vaporization dynamics of a bubble/droplet system encapsulated within a hyperelastic shell. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 143:23. [PMID: 29390781 DOI: 10.1121/1.5019467] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Nanodroplets have great, promising medical applications such as contrast imaging, embolotherapy, or targeted drug delivery. Their functions can be mechanically activated by means of focused ultrasound inducing a phase change of the inner liquid known as the acoustic droplet vaporization (ADV) process. In this context, a four-phases (vapor + liquid + shell + surrounding environment) model of ADV is proposed. Attention is especially devoted to the mechanical properties of the encapsulating shell, incorporating the well-known strain-softening behavior of Mooney-Rivlin material adapted to very large deformations of soft, nearly incompressible materials. Various responses to ultrasound excitation are illustrated, depending on linear and nonlinear mechanical shell properties and acoustical excitation parameters. Different classes of ADV outcomes are exhibited, and a relevant threshold ensuring complete vaporization of the inner liquid layer is defined. The dependence of this threshold with acoustical, geometrical, and mechanical parameters is also provided.
Collapse
Affiliation(s)
- Thomas Lacour
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7190, Institut Jean Le Rond ∂'Alembert, F-75005 Paris, France
| | - Matthieu Guédra
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7190, Institut Jean Le Rond ∂'Alembert, F-75005 Paris, France
| | - Tony Valier-Brasier
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7190, Institut Jean Le Rond ∂'Alembert, F-75005 Paris, France
| | - François Coulouvrat
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7190, Institut Jean Le Rond ∂'Alembert, F-75005 Paris, France
| |
Collapse
|
24
|
Vyas N, Dehghani H, Sammons RL, Wang QX, Leppinen DM, Walmsley AD. Imaging and analysis of individual cavitation microbubbles around dental ultrasonic scalers. ULTRASONICS 2017; 81:66-72. [PMID: 28595164 DOI: 10.1016/j.ultras.2017.05.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/23/2017] [Accepted: 05/23/2017] [Indexed: 06/07/2023]
Abstract
Cavitation is a potentially effective and less damaging method of removing biofilm from biomaterial surfaces. The aim of this study is to characterise individual microbubbles around ultrasonic scaler tips using high speed imaging and image processing. This information will provide improved understanding on the disruption of dental biofilm and give insights into how the instruments can be optimised for ultrasonic cleaning. Individual cavitation microbubbles around ultrasonic scalers were analysed using high speed recordings up to a million frames per second with image processing of the bubble movement. The radius and rate of bubble growth together with the collapse was calculated by tracking multiple points on bubbles over time. The tracking method to determine bubble speed demonstrated good inter-rater reliability (intra class correlation coefficient: 0.993) and can therefore be a useful method to apply in future studies. The bubble speed increased over its oscillation cycle and a maximum of 27ms-1 was recorded during the collapse phase. The maximum bubble radii ranged from 40 to 80μm. Bubble growth was observed when the ultrasonic scaler tip receded from an area and similarly bubble collapse was observed when the tip moved towards an area, corresponding to locations of low pressure around the scaler tip. Previous work shows that this cavitation is involved in biofilm removal. Future experimental work can be based on these findings by using the protocols developed to experimentally analyse cavitation around various clinical instruments and comparing with theoretical calculations. This will help to determine the main cleaning mechanisms of cavitation and how clinical instruments such as ultrasonic scalers can be optimised.
Collapse
Affiliation(s)
- N Vyas
- Physical Sciences of Imaging for Biomedical Sciences (PSIBS) Doctoral Training Centre, College of Engineering & Physical Sciences, University of Birmingham, Birmingham B15 2TT, UK; School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Mill Pool Way, Birmingham B5 7EG, UK
| | - H Dehghani
- School of Computer Science, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - R L Sammons
- School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Mill Pool Way, Birmingham B5 7EG, UK
| | - Q X Wang
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - D M Leppinen
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - A D Walmsley
- School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Mill Pool Way, Birmingham B5 7EG, UK.
| |
Collapse
|
25
|
Sheeran PS, Matsuura N, Borden MA, Williams R, Matsunaga TO, Burns PN, Dayton PA. Methods of Generating Submicrometer Phase-Shift Perfluorocarbon Droplets for Applications in Medical Ultrasonography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:252-263. [PMID: 27775902 PMCID: PMC5706463 DOI: 10.1109/tuffc.2016.2619685] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Continued advances in the field of ultrasound and ultrasound contrast agents have created new approaches to imaging and medical intervention. Phase-shift perfluorocarbon droplets, which can be vaporized by ultrasound energy to transition from the liquid to the vapor state, are one of the most highly researched alternatives to clinical ultrasound contrast agents (i.e., microbubbles). In this paper, part of a special issue on methods in biomedical ultrasonics, we survey current techniques to prepare ultrasound-activated nanoscale phase-shift perfluorocarbon droplets, including sonication, extrusion, homogenization, microfluidics, and microbubble condensation. We provide example protocols and discuss advantages and limitations of each approach. Finally, we discuss best practice in characterization of this class of contrast agents with respect to size distribution and ultrasound activation.
Collapse
|
26
|
Ishijima A, Tanaka J, Azuma T, Minamihata K, Yamaguchi S, Kobayashi E, Nagamune T, Sakuma I. The lifetime evaluation of vapourised phase-change nano-droplets. ULTRASONICS 2016; 69:97-105. [PMID: 27082763 DOI: 10.1016/j.ultras.2016.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 04/01/2016] [Accepted: 04/03/2016] [Indexed: 05/20/2023]
Abstract
Phase-change nano-droplets (PCNDs) are sub-micron particles that are coated with phospholipid and contain liquid-state perfluorocarbons such as perfluoropentane (boiling point=29°C) and perfluorohexane (boiling point=57°C), which can vapourise upon application of ultrasound. The bubbles generated by such reactions can serve as ultrasound contrast agents or HIFU sensitisers. However, the lifetime of bubbles generated from PCNDs on μs-order is not well known. Knowledge of the condition of PCND-derived bubbles on μs-order is essential for producing bubbles customised for specific purposes. In this study, we use an optical measurement system to measure the vapourisation and stability of the bubbles (bubble-lifetime) as well as the stability-controlling method of the nucleated bubbles on μs-order while changing the internal composition of PCNDs and the ambient temperature. PCND-derived bubbles remain in a bubble state when the boiling point of the internal composition is lower than the ambient temperature, but lose their optical contrast after approximately 10μs by re-condensation or dissolution when the boiling point of the internal composition is higher than the ambient temperature. We reveal that the superheating condition significantly affects the fate of vapourised PCNDs and that the bubble-lifetime can be controlled by changing both the ambient temperature conditions and the internal composition of PCNDs.
Collapse
Affiliation(s)
- Ayumu Ishijima
- Department of Precision Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
| | - Jun Tanaka
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
| | - Takashi Azuma
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan.
| | - Kosuke Minamihata
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
| | - Satoshi Yamaguchi
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, Japan
| | - Etsuko Kobayashi
- Department of Precision Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
| | - Teruyuki Nagamune
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
| | - Ichiro Sakuma
- Department of Precision Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
| |
Collapse
|
27
|
Healey AJ, Sontum PC, Kvåle S, Eriksen M, Bendiksen R, Tornes A, Østensen J. Acoustic Cluster Therapy: In Vitro and Ex Vivo Measurement of Activated Bubble Size Distribution and Temporal Dynamics. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1145-1166. [PMID: 26831341 DOI: 10.1016/j.ultrasmedbio.2015.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 12/07/2015] [Accepted: 12/14/2015] [Indexed: 06/05/2023]
Abstract
Acoustic cluster technology (ACT) is a two-component, microparticle formulation platform being developed for ultrasound-mediated drug delivery. Sonazoid microbubbles, which have a negative surface charge, are mixed with micron-sized perfluoromethylcyclopentane droplets stabilized with a positively charged surface membrane to form microbubble/microdroplet clusters. On exposure to ultrasound, the oil undergoes a phase change to the gaseous state, generating 20- to 40-μm ACT bubbles. An acoustic transmission technique is used to measure absorption and velocity dispersion of the ACT bubbles. An inversion technique computes bubble size population with temporal resolution of seconds. Bubble populations are measured both in vitro and in vivo after activation within the cardiac chambers of a dog model, with catheter-based flow through an extracorporeal measurement flow chamber. Volume-weighted mean diameter in arterial blood after activation in the left ventricle was 22 μm, with no bubbles >44 μm in diameter. After intravenous administration, 24.4% of the oil is activated in the cardiac chambers.
Collapse
|
28
|
Ang KM, Yeo LY, Friend JR, Hung YM, Tan MK. Acoustically enhanced heat transport. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:014902. [PMID: 26827343 DOI: 10.1063/1.4939757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10(6) Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ∼ 10(-9) m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ∼ 10(-8) m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10(-8) m with 10(6) Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.
Collapse
Affiliation(s)
- Kar M Ang
- School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| | - Leslie Y Yeo
- Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001, Australia
| | - James R Friend
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093, USA
| | - Yew Mun Hung
- School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| | - Ming K Tan
- School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| |
Collapse
|
29
|
Droplets, Bubbles and Ultrasound Interactions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 880:157-74. [DOI: 10.1007/978-3-319-22536-4_9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
30
|
Seda R, Li DS, Fowlkes JB, Bull JL. Characterization of Bioeffects on Endothelial Cells under Acoustic Droplet Vaporization. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:3241-52. [PMID: 26403698 PMCID: PMC4794981 DOI: 10.1016/j.ultrasmedbio.2015.07.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/19/2015] [Accepted: 07/16/2015] [Indexed: 05/11/2023]
Abstract
Gas embolotherapy is achieved by locally vaporizing microdroplets through acoustic droplet vaporization, which results in bubbles that are large enough to occlude blood flow directed to tumors. Endothelial cells, lining blood vessels, can be affected by these vaporization events, resulting in cell injury and cell death. An idealized monolayer of endothelial cells was subjected to acoustic droplet vaporization using a 3.5-MHz transducer and dodecafluoropentane droplets. Treatments included insonation pressures that varied from 2 to 8 MPa (rarefactional) and pulse lengths that varied from 4 to 16 input cycles. The bubble cloud generated was directly dependent on pressure, but not on pulse length. Cellular damage increased with increasing bubble cloud size, but was limited to the bubble cloud area. These results suggest that vaporization near the endothelium may impact the vessel wall, an effect that could be either deleterious or beneficial depending on the intended overall therapeutic application.
Collapse
Affiliation(s)
- Robinson Seda
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - David S Li
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Joseph L Bull
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.
| |
Collapse
|
31
|
Guédra M, Coulouvrat F. A model for acoustic vaporization of encapsulated droplets. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:3656-3667. [PMID: 26723321 DOI: 10.1121/1.4937747] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The use of encapsulated liquid nanoparticles is currently largely investigated for medical applications, mainly because their reduced size allows them to enter targeted areas which cannot be reached by large microbubbles (contrast agents). Low-boiling point perfluorocarbon droplets can be vaporized on-site under the action of the ultrasonic field, in order to turn them into echogeneous-eventually cavitating-microbubbles. This paper presents a theoretical model describing this phenomenon, paying particular attention to the finite size of the droplet and its encapsulation by a thin viscoelastic layer. Numerical simulations are done for droplets of radii 1 and 10 μm and for frequencies of 1-5 MHz. Results reveal that droplet surface tension and shell rigidity are responsible for an increase of the acoustic droplet vaporization threshold. Furthermore, this threshold does not vary monotonically with frequency, and an optimal frequency can be found to minimize it. Finally, the role of some physical properties on the dynamics of the particle is analyzed, such as the contrast of inner and outer liquids densities and the mechanical properties of the shell.
Collapse
Affiliation(s)
- Matthieu Guédra
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7190, Institut Jean Le Rond d'Alembert, F-75005 Paris, France
| | - François Coulouvrat
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7190, Institut Jean Le Rond d'Alembert, F-75005 Paris, France
| |
Collapse
|
32
|
Zhou Y. Application of acoustic droplet vaporization in ultrasound therapy. J Ther Ultrasound 2015; 3:20. [PMID: 26566442 PMCID: PMC4642755 DOI: 10.1186/s40349-015-0041-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/02/2015] [Indexed: 12/20/2022] Open
Abstract
Microbubbles have been used widely both in the ultrasonic diagnosis to enhance the contrast of vasculature and in ultrasound therapy to increase the bioeffects induced by bubble cavitation. However, due to their large size, the lifetime of microbubbles in the circulation system is on the order of minutes, and they cannot penetrate through the endothelial gap to enter the tumor. In an acoustic field, liquefied gas nanoparticles may be able to change the state and become the gas form in a few cycles of exposure without significant heating effects. Such a phenomenon is called as acoustic droplet vaporization (ADV). This review is intended to introduce the emerging application of ADV. The physics and the theoretical model behind it are introduced for further understanding of the mechanisms. Current manufacturing approaches are provided, and their differences are compared. Based on the characteristic of phase shift, a variety of therapeutic applications have been carried out both in vitro and in vivo. The latest progress and interesting results of vessel occlusion, thermal ablation using high-intensity focused ultrasound (HIFU), localized drug delivery to the tumor and cerebral tissue through the blood-brain barrier, localized tissue erosion by histotripsy are summarized. ADV may be able to overcome some limitations of microbubble-mediated ultrasound therapy and provide a novel drug and molecular targeting carrier. More investigation will help progress this technology forward for clinical translation.
Collapse
Affiliation(s)
- Yufeng Zhou
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798 Singapore
| |
Collapse
|
33
|
Sheeran PS, Rojas JD, Puett C, Hjelmquist J, Arena CB, Dayton PA. Contrast-enhanced ultrasound imaging and in vivo circulatory kinetics with low-boiling-point nanoscale phase-change perfluorocarbon agents. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:814-31. [PMID: 25619781 PMCID: PMC5599113 DOI: 10.1016/j.ultrasmedbio.2014.10.020] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 05/03/2023]
Abstract
Many studies have explored phase-change contrast agents (PCCAs) that can be vaporized by an ultrasonic pulse to form microbubbles for ultrasound imaging and therapy. However, few investigations have been published on the utility and characteristics of PCCAs as contrast agents in vivo. In this study, we examine the properties of low-boiling-point nanoscale PCCAs evaluated in vivo and compare data with those for conventional microbubbles with respect to contrast generation and circulation properties. To do this, we develop a custom pulse sequence to vaporize and image PCCAs using the Verasonics research platform and a clinical array transducer. Results indicate that droplets can produce contrast enhancement similar to that of microbubbles (7.29 to 18.24 dB over baseline, depending on formulation) and can be designed to circulate for as much as 3.3 times longer than microbubbles. This study also reports for the first time the ability to capture contrast washout kinetics of the target organ as a measure of vascular perfusion.
Collapse
Affiliation(s)
- Paul S Sheeran
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Connor Puett
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Jordan Hjelmquist
- Department of Biomedical Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Christopher B Arena
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
| |
Collapse
|
34
|
Doinikov AA, Sheeran PS, Bouakaz A, Dayton PA. Vaporization dynamics of volatile perfluorocarbon droplets: a theoretical model and in vitro validation. Med Phys 2014; 41:102901. [PMID: 25281982 PMCID: PMC4290562 DOI: 10.1118/1.4894804] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/01/2014] [Accepted: 08/20/2014] [Indexed: 01/10/2023] Open
Abstract
PURPOSE Perfluorocarbon (PFC) microdroplets, called phase-change contrast agents (PCCAs), are a promising tool in ultrasound imaging and therapy. Interest in PCCAs is motivated by the fact that they can be triggered to transition from the liquid state to the gas state by an externally applied acoustic pulse. This property opens up new approaches to applications in ultrasound medicine. Insight into the physics of vaporization of PFC droplets is vital for effective use of PCCAs and for anticipating bioeffects. PCCAs composed of volatile PFCs (with low boiling point) exhibit complex dynamic behavior: after vaporization by a short acoustic pulse, a PFC droplet turns into a vapor bubble which undergoes overexpansion and damped radial oscillation until settling to a final diameter. This behavior has not been well described theoretically so far. The purpose of our study is to develop an improved theoretical model that describes the vaporization dynamics of volatile PFC droplets and to validate this model by comparison with in vitro experimental data. METHODS The derivation of the model is based on applying the mathematical methods of fluid dynamics and thermodynamics to the process of the acoustic vaporization of PFC droplets. The used approach corrects shortcomings of the existing models. The validation of the model is carried out by comparing simulated results with in vitro experimental data acquired by ultrahigh speed video microscopy for octafluoropropane (OFP) and decafluorobutane (DFB) microdroplets of different sizes. RESULTS The developed theory allows one to simulate the growth of a vapor bubble inside a PFC droplet until the liquid PFC is completely converted into vapor, and the subsequent overexpansion and damped oscillations of the vapor bubble, including the influence of an externally applied acoustic pulse. To evaluate quantitatively the difference between simulated and experimental results, the L2-norm errors were calculated for all cases where the simulated and experimental results are compared. These errors were found to be in the ranges of 0.043-0.067 and 0.037-0.088 for OFP and DFB droplets, respectively. These values allow one to consider agreement between the simulated and experimental results as good. This agreement is attained by varying only 2 of 16 model parameters which describe the material properties of gaseous and liquid PFCs and the liquid surrounding the PFC droplet. The fitting parameters are the viscosity and the surface tension of the surrounding liquid. All other model parameters are kept invariable. CONCLUSIONS The good agreement between the theoretical and experimental results suggests that the developed model is able to correctly describe the key physical processes underlying the vaporization dynamics of volatile PFC droplets. The necessity of varying the parameters of the surrounding liquid for fitting the experimental curves can be explained by the fact that the parts of the initial phospholipid shell of PFC droplets remain on the surface of vapor bubbles at the oscillatory stage and their presence affects the bubble dynamics.
Collapse
Affiliation(s)
| | - Paul S Sheeran
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599
| | - Ayache Bouakaz
- Inserm U930, Université François Rabelais, Tours 37044, France
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599
| |
Collapse
|
35
|
Kang ST, Lin YC, Yeh CK. Mechanical bioeffects of acoustic droplet vaporization in vessel-mimicking phantoms. ULTRASONICS SONOCHEMISTRY 2014; 21:1866-74. [PMID: 24690297 DOI: 10.1016/j.ultsonch.2014.03.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/10/2014] [Accepted: 03/10/2014] [Indexed: 05/13/2023]
Abstract
This study investigated the mechanical bioeffects exerted by acoustic droplet vaporization (ADV) under different experimental conditions using vessel phantoms with a 200-μm inner diameter but different stiffness for imitating the microvasculature in various tumors. High-speed microscopy, passive cavitation detection, and ultrasound attenuation measurement were conducted to determine the morphological characteristics of vascular damage and clarify the mechanisms by which the damage was initiated and developed. The results show that phantom erosion was initiated under successive ultrasound exposure (2 MHz, 3 cycles) at above 8-MPa peak negative pressures (PNPs) when ADV occurred with inertial cavitation (IC), producing lesions whose morphological characteristics were dependent on the amount of vaporized droplets. Slight injury occurred at droplet concentrations below (2.6±0.2)×10(6) droplets/mL, forming shallow and rugged surfaces on both sides of the vessel walls. Increasing the droplet concentration to up to (2.6±0.2)×10(7) droplets/mL gradually suppressed the damage on the distal wall, and turned the rugged surface on the proximal wall into tunnels rapidly elongating in the direction opposite to ultrasound propagation. Increasing the PNP did not increase the maximum tunnel depth after the ADV efficiency reached a plateau (about 71.6±2.7% at 10 MPa). Increasing the pulse duration effectively increased the maximum tunnel depth to more than 10 times the diameter of the vessel even though there was no marked enhancement in IC dose. It can be inferred that substantial bubble generation in single ADV events may simultaneously distort the acoustic pressure distribution. The backward ultrasound reinforcement and forward ultrasound shielding relative to the direction of wave propagation augment the propensity of backward erosion. The results of the present work provide information that is valuable for the prevention or utilization of ADV-mediated mechanical bioeffects in clinical applications.
Collapse
Affiliation(s)
- Shih-Tsung Kang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Chen Lin
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Chih-Kuang Yeh
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan.
| |
Collapse
|
36
|
Reznik N, Lajoinie G, Shpak O, Gelderblom EC, Williams R, de Jong N, Versluis M, Burns PN. On the acoustic properties of vaporized submicron perfluorocarbon droplets. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1379-84. [PMID: 24462162 DOI: 10.1016/j.ultrasmedbio.2013.11.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/19/2013] [Accepted: 11/20/2013] [Indexed: 05/22/2023]
Abstract
The acoustic characteristics of microbubbles created from vaporized submicron perfluorocarbon droplets with fluorosurfactant coating are examined. Utilizing ultra-high-speed optical imaging, the acoustic response of individual microbubbles to low-intensity diagnostic ultrasound was observed on clinically relevant time scales of hundreds of milliseconds after vaporization. It was found that the vaporized droplets oscillate non-linearly and exhibit a resonant bubble size shift and increased damping relative to uncoated gas bubbles due to the presence of coating material. Unlike the commercially available lipid-coated ultrasound contrast agents, which may exhibit compression-only behavior, vaporized droplets may exhibit expansion-dominated oscillations. It was further observed that the non-linearity of the acoustic response of the bubbles was comparable to that of SonoVue microbubbles. These results suggest that vaporized submicron perfluorocarbon droplets possess the acoustic characteristics necessary for their potential use as ultrasound contrast agents in clinical practice.
Collapse
Affiliation(s)
- Nikita Reznik
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
| | - Guillaume Lajoinie
- Physics of Fluids Group and MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Oleksandr Shpak
- Physics of Fluids Group and MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Erik C Gelderblom
- Physics of Fluids Group and MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Ross Williams
- Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Nico de Jong
- Biomedical Engineering Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Michel Versluis
- Physics of Fluids Group and MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Peter N Burns
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Toronto, Ontario, Canada
| |
Collapse
|
37
|
Ozcelik A, Ahmed D, Xie Y, Nama N, Qu Z, Nawaz AA, Huang TJ. An acoustofluidic micromixer via bubble inception and cavitation from microchannel sidewalls. Anal Chem 2014; 86:5083-8. [PMID: 24754496 PMCID: PMC4033639 DOI: 10.1021/ac5007798] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
During the deep reactive ion etching process, the sidewalls of a silicon mold feature rough wavy structures, which can be transferred onto a polydimethylsiloxane (PDMS) microchannel through the soft lithography technique. In this article, we utilized the wavy structures of PDMS microchannel sidewalls to initiate and cavitate bubbles in the presence of acoustic waves. Through bubble cavitation, this acoustofluidic approach demonstrates fast, effective mixing in microfluidics. We characterized its performance by using viscous fluids such as poly(ethylene glycol) (PEG). When two PEG solutions with a resultant viscosity 54.9 times higher than that of water were used, the mixing efficiency was found to be 0.92, indicating excellent, homogeneous mixing. The acoustofluidic micromixer presented here has the advantages of simple fabrication, easy integration, and capability to mix high-viscosity fluids (Reynolds number: ~0.01) in less than 100 ms.
Collapse
Affiliation(s)
- Adem Ozcelik
- Department of Engineering Science and Mechanics, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | | | | | | | | | | | | |
Collapse
|
38
|
Xu S, Zong Y, Li W, Zhang S, Wan M. Bubble size distribution in acoustic droplet vaporization via dissolution using an ultrasound wide-beam method. ULTRASONICS SONOCHEMISTRY 2014; 21:975-983. [PMID: 24360840 DOI: 10.1016/j.ultsonch.2013.11.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/26/2013] [Accepted: 11/28/2013] [Indexed: 06/03/2023]
Abstract
Performance and efficiency of numerous cavitation enhanced applications in a wide range of areas depend on the cavitation bubble size distribution. Therefore, cavitation bubble size estimation would be beneficial for biological and industrial applications that rely on cavitation. In this study, an acoustic method using a wide beam with low pressure is proposed to acquire the time intensity curve of the dissolution process for the cavitation bubble population and then determine the bubble size distribution. Dissolution of the cavitation bubbles in saline and in phase-shift nanodroplet emulsion diluted with undegassed or degassed saline was obtained to quantify the effects of pulse duration (PD) and acoustic power (AP) or peak negative pressure (PNP) of focused ultrasound on the size distribution of induced cavitation bubbles. It was found that an increase of PD will induce large bubbles while AP had only a little effect on the mean bubble size in saline. It was also recognized that longer PD and higher PNP increases the proportions of large and small bubbles, respectively, in suspensions of phase-shift nanodroplet emulsions. Moreover, degassing of the suspension tended to bring about smaller mean bubble size than the undegassed suspension. In addition, condensation of cavitation bubble produced in diluted suspension of phase-shift nanodroplet emulsion was involved in the calculation to discuss the effect of bubble condensation in the bubble size estimation in acoustic droplet vaporization. It was shown that calculation without considering the condensation might underestimate the mean bubble size and the calculation with considering the condensation might have more influence over the size distribution of small bubbles, but less effect on that of large bubbles. Without or with considering bubble condensation, the accessible minimum bubble radius was 0.4 or 1.7 μm and the step size was 0.3 μm. This acoustic technique provides an approach to estimate the size distribution of cavitation bubble population in opaque media and might be a promising tool for applications where it is desirable to tune the ultrasound parameters to control the size distribution of cavitation bubbles.
Collapse
Affiliation(s)
- Shanshan Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Yujin Zong
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Wusong Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Siyuan Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
| |
Collapse
|
39
|
Kang ST, Huang YL, Yeh CK. Characterization of acoustic droplet vaporization for control of bubble generation under flow conditions. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:551-61. [PMID: 24433748 DOI: 10.1016/j.ultrasmedbio.2013.10.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 10/20/2013] [Accepted: 10/21/2013] [Indexed: 05/14/2023]
Abstract
This study investigated the manipulation of bubbles generated by acoustic droplet vaporization (ADV) under clinically relevant flow conditions. Optical microscopy and high-frequency ultrasound imaging were used to observe bubbles generated by 2-MHz ultrasound pulses at different time points after the onset of ADV. The dependence of the bubble population on droplet concentration, flow velocity, fluid viscosity and acoustic parameters, including acoustic pressure, pulse duration and pulse repetition frequency, was investigated. The results indicated that post-ADV bubble growth spontaneously driven by air permeation markedly affected the bubble population after insonation. The bubbles can grow to a stable equilibrium diameter as great as twice the original diameter in 0.5-1 s, as predicted by the theoretical calculation. The growth trend is independent of flow velocity, but dependent on fluid viscosity and droplet concentration, which directly influence the rate of gas uptake by bubbles and the rate of gas exchange across the wall of the semipermeable tube containing the bubbles and, hence, the gas content of the host medium. Varying the acoustic pressure does not markedly change the formation of bubbles as long as the ADV thresholds of most droplets are reached. Varying pulse duration and pulse repetition frequency markedly reduces the number of bubbles. Lengthening pulse duration favors the production of large bubbles, but reduces the total number of bubbles. Increasing the PRF interestingly provides superior performance in bubble disruption. These results also suggest that an ADV bubble population cannot be assessed simply on the basis of initial droplet size or enhancement of imaging contrast by the bubbles. Determining the optimal acoustic parameters requires careful consideration of their impact on the bubble population produced for different application scenarios.
Collapse
Affiliation(s)
- Shih-Tsung Kang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Luan Huang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Chih-Kuang Yeh
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan.
| |
Collapse
|
40
|
Li DS, Kripfgans OD, Fabiilli ML, Brian Fowlkes J, Bull JL. Formation of toroidal bubbles from acoustic droplet vaporization. APPLIED PHYSICS LETTERS 2014; 104:063706. [PMID: 24711672 PMCID: PMC3965339 DOI: 10.1063/1.4864289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 01/23/2014] [Indexed: 05/24/2023]
Abstract
Acoustic droplet vaporization (ADV) is the selective vaporization of liquid microdroplets using ultrasound to produce stable gas bubbles. ADV is the primary mechanism in an ultrasound based cancer therapy, called gas embolotherapy, where the resulting bubbles are used to create localized occlusions leading to tumor necrosis. In this investigation, early time scale events including phase change are directly visualized using ultra-high speed imaging. Modulating elevated acoustic pressure or pulse length resulted in toroidal bubbles. For sufficiently short pulses (4 cycles at 7.5 MHz), toroidal bubble formation could be avoided, regardless of acoustic pressures tested.
Collapse
Affiliation(s)
- David S Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Oliver D Kripfgans
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Joseph L Bull
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| |
Collapse
|
41
|
Li DS, Kripfgans OD, Fabiilli ML, Brian Fowlkes J, Bull JL. Initial nucleation site formation due to acoustic droplet vaporization. APPLIED PHYSICS LETTERS 2014; 104:063703. [PMID: 24711671 PMCID: PMC3970834 DOI: 10.1063/1.4864110] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/02/2014] [Indexed: 05/20/2023]
Abstract
Acoustic droplet vaporization (ADV) is the selective vaporization of liquid microdroplets using ultrasound, resulting in gas bubbles. The ADV process has been proposed as a tool in biomedical applications such as gas embolotherapy, drug delivery, and phase-change contrast agents. Using a 7.5 MHz focused transducer, the initial gas nucleus formed in perfluorocarbon microdroplets was directly visualized using ultra-high speed imaging. The experimental results of initial nucleation site location were compared to a 2D axisymmetric linear acoustic model investigating the focal spot of the acoustic wave within the microdroplets. Results suggest a wavelength to droplet diameter dependence on nucleation site formation.
Collapse
Affiliation(s)
- David S Li
- University of Michigan, Ann Arbor, Michigan 48109, USA
| | | | | | | | - Joseph L Bull
- University of Michigan, Ann Arbor, Michigan 48109, USA
| |
Collapse
|
42
|
Acoustic droplet vaporization is initiated by superharmonic focusing. Proc Natl Acad Sci U S A 2014; 111:1697-702. [PMID: 24449879 DOI: 10.1073/pnas.1312171111] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acoustically sensitive emulsion droplets composed of a liquid perfluorocarbon have the potential to be a highly efficient system for local drug delivery, embolotherapy, or for tumor imaging. The physical mechanisms underlying the acoustic activation of these phase-change emulsions into a bubbly dispersion, termed acoustic droplet vaporization, have not been well understood. The droplets have a very high activation threshold; its frequency dependence does not comply with homogeneous nucleation theory and localized nucleation spots have been observed. Here we show that acoustic droplet vaporization is initiated by a combination of two phenomena: highly nonlinear distortion of the acoustic wave before it hits the droplet and focusing of the distorted wave by the droplet itself. At high excitation pressures, nonlinear distortion causes significant superharmonics with wavelengths of the order of the droplet size. These superharmonics strongly contribute to the focusing effect; therefore, the proposed mechanism also explains the observed pressure thresholding effect. Our interpretation is validated with experimental data captured with an ultrahigh-speed camera on the positions of the nucleation spots, where we find excellent agreement with the theoretical prediction. Moreover, the presented mechanism explains the hitherto counterintuitive dependence of the nucleation threshold on the ultrasound frequency. The physical insight allows for the optimization of acoustic droplet vaporization for therapeutic applications, in particular with respect to the acoustic pressures required for activation, thereby minimizing the negative bioeffects associated with the use of high-intensity ultrasound.
Collapse
|
43
|
Sheeran PS, Dayton PA. Improving the performance of phase-change perfluorocarbon droplets for medical ultrasonography: current progress, challenges, and prospects. SCIENTIFICA 2014; 2014:579684. [PMID: 24991447 PMCID: PMC4058811 DOI: 10.1155/2014/579684] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/02/2014] [Indexed: 05/12/2023]
Abstract
Over the past two decades, perfluorocarbon (PFC) droplets have been investigated for biomedical applications across a wide range of imaging modalities. More recently, interest has increased in "phase-change" PFC droplets (or "phase-change" contrast agents), which can convert from liquid to gas with an external energy input. In the field of ultrasound, phase-change droplets present an attractive alternative to traditional microbubble agents for many diagnostic and therapeutic applications. Despite the progress, phase-change PFC droplets remain far from clinical implementation due to a number of challenges. In this review, we survey our recent work to enhance the performance of phase-change agents for ultrasound through a variety of techniques in order to provide increased efficacy in therapeutic applications of ultrasound and enable previously unexplored applications in diagnostic and molecular imaging.
Collapse
Affiliation(s)
- Paul S. Sheeran
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC 27599, USA
| | - Paul A. Dayton
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC 27599, USA
- *Paul A. Dayton:
| |
Collapse
|
44
|
Sheeran PS, Matsunaga TO, Dayton PA. Phase change events of volatile liquid perfluorocarbon contrast agents produce unique acoustic signatures. Phys Med Biol 2013; 59:379-401. [PMID: 24351961 DOI: 10.1088/0031-9155/59/2/379] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Phase-change contrast agents (PCCAs) provide a dynamic platform to approach problems in medical ultrasound (US). Upon US-mediated activation, the liquid core vaporizes and expands to produce a gas bubble ideal for US imaging and therapy. In this study, we demonstrate through high-speed video microscopy and US interrogation that PCCAs composed of highly volatile perfluorocarbons (PFCs) exhibit unique acoustic behavior that can be detected and differentiated from standard microbubble contrast agents. Experimental results show that when activated with short pulses PCCAs will over-expand and undergo unforced radial oscillation while settling to a final bubble diameter. The size-dependent oscillation phenomenon generates a unique acoustic signal that can be passively detected in both time and frequency domain using confocal piston transducers with an 'activate high' (8 MHz, 2 cycles), 'listen low' (1 MHz) scheme. Results show that the magnitude of the acoustic 'signature' increases as PFC boiling point decreases. By using a band-limited spectral processing technique, the droplet signals can be isolated from controls and used to build experimental relationships between concentration and vaporization pressure. The techniques shown here may be useful for physical studies as well as development of droplet-specific imaging techniques.
Collapse
Affiliation(s)
- Paul S Sheeran
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC 27599, USA
| | | | | |
Collapse
|
45
|
Lin CY, Pitt WG. Acoustic droplet vaporization in biology and medicine. BIOMED RESEARCH INTERNATIONAL 2013; 2013:404361. [PMID: 24350267 PMCID: PMC3853706 DOI: 10.1155/2013/404361] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/17/2013] [Accepted: 10/03/2013] [Indexed: 01/20/2023]
Abstract
This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV) in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but its use declined rapidly with the advent of other imaging agents. In the last decade, ADV was proposed and explored for embolic occlusion therapy, drug delivery, aberration correction, and high intensity focused ultrasound (HIFU) sensitization. Vessel occlusion via ADV has been explored in rodents and dogs and may be approaching clinical use. ADV for drug delivery is still in preclinical stages with initial applications to treat tumors in mice. Other techniques are still in preclinical studies but have potential for clinical use in specialty applications. Overall, ADV has a bright future in clinical application because the small size of nanodroplets greatly reduces the rate of clearance compared to larger contrast agent bubbles and yet provides the advantages of ultrasonographic contrast, acoustic cavitation, and nontoxicity of conventional perfluorocarbon contrast agent bubbles.
Collapse
Affiliation(s)
- Chung-Yin Lin
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
- Department of Neurosurgery, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
- Division of Clinical Toxicology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
| | - William G. Pitt
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| |
Collapse
|
46
|
Sheeran PS, Matsunaga TO, Dayton PA. Phase-transition thresholds and vaporization phenomena for ultrasound phase-change nanoemulsions assessed via high-speed optical microscopy. Phys Med Biol 2013; 58:4513-34. [PMID: 23760161 DOI: 10.1088/0031-9155/58/13/4513] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ultrasonically activated phase-change contrast agents (PCCAs) based on perfluorocarbon droplets have been proposed for a variety of therapeutic and diagnostic clinical applications. When generated at the nanoscale, droplets may be small enough to exit the vascular space and then be induced to vaporize with high spatial and temporal specificity by externally-applied ultrasound. The use of acoustical techniques for optimizing ultrasound parameters for given applications can be a significant challenge for nanoscale PCCAs due to the contributions of larger outlier droplets. Similarly, optical techniques can be a challenge due to the sub-micron size of nanodroplet agents and resolution limits of optical microscopy. In this study, an optical method for determining activation thresholds of nanoscale emulsions based on the in vitro distribution of bubbles resulting from vaporization of PCCAs after single, short (<10 cycles) ultrasound pulses is evaluated. Through ultra-high-speed microscopy it is shown that the bubbles produced early in the pulse from vaporized droplets are strongly affected by subsequent cycles of the vaporization pulse, and these effects increase with pulse length. Results show that decafluorobutane nanoemulsions with peak diameters on the order of 200 nm can be optimally vaporized with short pulses using pressures amenable to clinical diagnostic ultrasound machines.
Collapse
Affiliation(s)
- Paul S Sheeran
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, NC 27599, USA
| | | | | |
Collapse
|