1
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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.
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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.
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2
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Cattaneo M, Supponen O. Shell viscosity estimation of lipid-coated microbubbles. SOFT MATTER 2023; 19:5925-5941. [PMID: 37490014 DOI: 10.1039/d3sm00871a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Understanding the shell rheology of ultrasound contrast agent microbubbles is vital for anticipating their bioeffects in clinical practice. Past studies using sophisticated acoustic and optical techniques have made enormous progress in this direction, enabling the development of shell models that adequately reproduce the nonlinear behaviour of the coated microbubble under acoustic excitation. However, there have also been puzzling discrepancies and missing physical explanations for the dependency of shell viscosity on the equilibrium bubble radius, which demands further experimental investigations. In this study, we aim to unravel the cause of such behaviour by performing a refined characterisation of the shell viscosity. We use ultra-high-speed microscopy imaging, optical trapping and wide-field fluorescence to accurately record the individual microbubble response upon ultrasound driving across a range of bubble sizes. An advanced model of bubble dynamics is validated and employed to infer the shell viscosity of single bubbles from their radial time evolution. The resulting values reveal a prominent variability of the shell viscosity of about an order of magnitude and no dependency on the bubble size, which is contrary to previous studies. We find that the method called bubble spectroscopy, which has been used extensively in the past to determine the shell viscosity, is highly sensitive to methodology inaccuracies, and we demonstrate through analytical arguments that the previously reported unphysical trends are an artifact of these biases. We also show the importance of correct bubble sizing, as errors in this aspect can also lead to unphysical trends in shell viscosity, when estimated through a nonlinear fitting from the time response of the bubble.
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Affiliation(s)
- Marco Cattaneo
- Institute of Fluid Dynamics, Department of Mechanical and Process Engineering, ETH Zürich, Sonneggstrasse 3, 8092 Zürich, Switzerland.
| | - Outi Supponen
- Institute of Fluid Dynamics, Department of Mechanical and Process Engineering, ETH Zürich, Sonneggstrasse 3, 8092 Zürich, Switzerland.
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3
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Koushki E, Ghasedi A, Tayebee R. Origins of photoacoustic effect in solutions with a single non-pulsed continue wave laser beam; study on the CrTPP solutions. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.113811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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4
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Deurvorst FR, Collado Lara G, Matalliotakis A, Vos HJ, de Jong N, Daeichin V, Verweij MD. A spatial and temporal characterisation of single proton acoustic waves in proton beam cancer therapy. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:1200. [PMID: 35232071 DOI: 10.1121/10.0009567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
An in vivo range verification technology for proton beam cancer therapy, preferably in real-time and with submillimeter resolution, is desired to reduce the present uncertainty in dose localization. Acoustical imaging technologies exploiting possible local interactions between protons and microbubbles or nanodroplets might be an interesting option. Unfortunately, a theoretical model capable of characterising the acoustical field generated by an individual proton on nanometer and micrometer scales is still missing. In this work, such a model is presented. The proton acoustic field is generated by the adiabatic expansion of a region that is locally heated by a passing proton. To model the proton heat deposition, secondary electron production due to protons has been quantified using a semi-empirical model based on Rutherford's scattering theory, which reproduces experimentally obtained electronic stopping power values for protons in water within 10% over the full energy range. The electrons transfer energy into heat via electron-phonon coupling to atoms along the proton track. The resulting temperature increase is calculated using an inelastic thermal spike model. Heat deposition can be regarded as instantaneous, thus, stress confinement is ensured and acoustical initial conditions are set. The resulting thermoacoustic field in the nanometer and micrometer range from the single proton track is computed by solving the thermoacoustic wave equation using k-space Green's functions, yielding the characteristic amplitudes and frequencies present in the acoustic signal generated by a single proton in an aqueous medium. Wavefield expansion and asymptotic approximations are used to extend the spatial and temporal ranges of the proton acoustic field.
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Affiliation(s)
- F R Deurvorst
- Medical Imaging, Imaging Physics, Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - G Collado Lara
- Biomedical Engineering, Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - A Matalliotakis
- Medical Imaging, Imaging Physics, Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - H J Vos
- Biomedical Engineering, Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - N de Jong
- Medical Imaging, Imaging Physics, Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - V Daeichin
- Medical Imaging, Imaging Physics, Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - M D Verweij
- Medical Imaging, Imaging Physics, Applied Sciences, Delft University of Technology, Delft, the Netherlands
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5
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Langeveld SAG, Meijlink B, Beekers I, Olthof M, van der Steen AFW, de Jong N, Kooiman K. Theranostic Microbubbles with Homogeneous Ligand Distribution for Higher Binding Efficacy. Pharmaceutics 2022; 14:pharmaceutics14020311. [PMID: 35214044 PMCID: PMC8878664 DOI: 10.3390/pharmaceutics14020311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 02/05/2023] Open
Abstract
Phospholipid-coated targeted microbubbles are used for ultrasound molecular imaging and locally enhanced drug delivery, with the binding efficacy being an important trait. The use of organic solvent in microbubble production makes the difference between a heterogeneous or homogeneous ligand distribution. This study demonstrates the effect of ligand distribution on the binding efficacy of phospholipid-coated ανβ3-targeted microbubbles in vitro using a monolayer of human umbilical-vein endothelial cells and in vivo using chicken embryos. Microbubbles with a homogeneous ligand distribution had a higher binding efficacy than those with a heterogeneous ligand distribution both in vitro and in vivo. In vitro, 1.55× more microbubbles with a homogeneous ligand distribution bound under static conditions, while this was 1.49× more under flow with 1.25 dyn/cm2, 1.56× more under flow with 2.22 dyn/cm2, and 1.25× more in vivo. The in vitro dissociation rate of bound microbubbles with homogeneous ligand distribution was lower at low shear stresses (1–5 dyn/cm2). The internalized depth of bound microbubbles was influenced by microbubble size, not by ligand distribution. In conclusion, for optimal binding the use of organic solvent in targeted microbubble production is preferable over directly dispersing phospholipids in aqueous medium.
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Affiliation(s)
- Simone A. G. Langeveld
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
- Correspondence:
| | - Bram Meijlink
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
| | - Inés Beekers
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
- Department of Health, ORTEC B.V., 2719 EA Zoetermeer, The Netherlands
| | - Mark Olthof
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
| | - Antonius F. W. van der Steen
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
| | - Nico de Jong
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
- Imaging Physics, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - Klazina Kooiman
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
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6
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Kuriakose M, Borden MA. Microbubbles and Nanodrops for photoacoustic tomography. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101464] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Chattaraj R, Hammer DA, Lee D, Sehgal CM. Multivariable Dependence of Acoustic Contrast of Fluorocarbon and Xenon Microbubbles under Flow. ULTRASOUND IN MEDICINE & BIOLOGY 2021; 47:2676-2691. [PMID: 34112553 PMCID: PMC8355047 DOI: 10.1016/j.ultrasmedbio.2021.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 04/21/2021] [Accepted: 04/25/2021] [Indexed: 06/12/2023]
Abstract
Microbubbles (MBs) are 1 to 10 µm gas particles stabilized by an amphiphilic shell capable of responding to biomedical ultrasound with strong acoustic signals, allowing them to be commonly used in ultrasound imaging and therapy. The composition of both the shell and the core determines their stability and acoustic properties. While there has been extensive characterization of the dissolution, oscillation, cavitation, collapse and therefore, ultrasound contrast of MBs under static conditions, few reports have examined such behavior under hydrodynamic flow. In this study, we evaluate the interplay of ultrasound parameters (five different mechanical indices [MIs]), MB shell parameter (shell stiffness), type of gas (perfluorocarbon for diagnostic imaging and xenon as a therapeutic gas), and a flow parameter (flow rate) on the ultrasound signal of phospholipid-stabilized MBs flowing through a latex tube embedded in a tissue-mimicking phantom. We find that the contrast gradient (CG), a metric of the rate of decay of contrast along the length of the tube, and the contrast peak (CP), the location where the maximum contrast is reached, depend on the conditions of flow, imaging, and MB material. For instance, while the contrast near the flow inlet of the field of view is highest for a softer shell (dipalmitoylphosphatidylcholine [DPPC], C16) than for stiffer shells (distearoylphosphatidylcholine [DSPC], C18, and dibehenoylphosphatidylcholine [DBPC], C22), the contrast decay is also faster; stiffer shells provide more resistance and hence lead to slower MB dissolution/destruction. At higher flow rates, the CG is low for a fixed length of time because each MB is exposed to ultrasound for a shorter period. The CG becomes high for low flow rates, especially at high incident pressures (high MI), causing more MB destruction closer to the inlet of the field of view. Also, the CP shifts toward the inlet at low flow rates, high MIs, and low shell stiffness. We also report the first demonstration of sustained ultrasound flow imaging of a water-soluble, therapeutic gas MB (xenon). We find that an increased MB concentration is necessary for obtaining the same signal magnitude for xenon MBs. In summary, this study builds a framework depicting how multiple variables simultaneously affect the evolution of MB ultrasound contrast under flow. Depending on the MB composition, imaging conditions, transducer positioning, and image processing, building on such a framework could potentially allow for extraction of additional diagnostic information than is commonly analyzed for physiological flow.
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Affiliation(s)
- Rajarshi Chattaraj
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel A Hammer
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Chandra M Sehgal
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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8
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Collado-Lara G, Heymans SV, Godart J, D'Agostino E, D'hooge J, Van Den Abeele K, Vos HJ, de Jong N. Effect of a Radiotherapeutic Megavoltage Beam on Ultrasound Contrast Agents. ULTRASOUND IN MEDICINE & BIOLOGY 2021; 47:1857-1867. [PMID: 33810887 DOI: 10.1016/j.ultrasmedbio.2021.02.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Collateral damage to healthy surrounding tissue during conventional radiotherapy increases when deviations from the treatment plan occur. Ultrasound contrast agents (UCAs) are a possible candidate for radiation dose monitoring. This study investigated the size distribution and acoustic response of two commercial formulations, SonoVue/Lumason and Definity/Luminity, as a function of dose on clinical megavoltage photon beam exposure (24 Gy). SonoVue samples exhibited a decrease in concentration of bubbles smaller than 7 µm, together with an increase in acoustic attenuation and a decrease in acoustic scattering. Definity samples did not exhibit a significant response to radiation, suggesting that the effect of megavoltage photons depends on the UCA formulation. For SonoVue, the influence of the megavoltage photon beam was especially apparent at the second harmonic frequency, and can be captured using pulse inversion and amplitude modulation (3.5-dB decrease for the maximum dose), which could eventually be used for dosimetry in a well-controlled environment.
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Affiliation(s)
- Gonzalo Collado-Lara
- Biomedical Engineering, Department of Cardiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
| | - Sophie V Heymans
- Department of Physics, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Jeremy Godart
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | | | - Jan D'hooge
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | | | - Hendrik J Vos
- Biomedical Engineering, Department of Cardiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Nico de Jong
- Biomedical Engineering, Department of Cardiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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9
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Daeichin V, Inzunza-Ibarra MA, Lum JS, Borden MA, Murray TW. Photoacoustic Impulse Response of Lipid-Coated Ultrasound Contrast Agents. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2311-2314. [PMID: 33460371 PMCID: PMC8210856 DOI: 10.1109/tuffc.2021.3052140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The utility of ultrasound imaging and therapy with microbubbles may be greatly enhanced by determining their impulse-response dynamics as a function of size and composition. Prior methods for microbubble characterization utilizing high-speed cameras, acoustic transducers and laser-based techniques typically scan a limited frequency range. Here, we report on the use of a novel photoacoustic technique to measure the impulse response of single microbubbles. Individual microbubbles are driven with a broadband photoacoustic wave generated by a nanosecond-pulse laser illuminating an optical absorber. The resulting microbubble oscillations were detected by following transmission of a second laser as it passes twice through the microbubble. The system could even resolve oscillations resulting from a single-shot. As a proof-of-concept study, the size-dependent, linear impulse response of lipid-coated microbubbles was characterized using this technique. This unique method of microbubble characterization with exceptional spatiotemporal resolution opens new avenues for capturing and analyzing microbubble system dynamics.
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10
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Thomas AN, Song KH, Upadhyay A, Papadopoulou V, Ramirez D, Benninger RKP, Lowerison M, Song P, Murray TW, Borden MA. Contrast-Enhanced Sonography with Biomimetic Lung Surfactant Nanodrops. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2386-2396. [PMID: 33566623 PMCID: PMC8988746 DOI: 10.1021/acs.langmuir.0c03349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nanodrops comprising a perfluorocarbon liquid core can be acoustically vaporized into echogenic microbubbles for ultrasound imaging. Packaging the microbubble in its condensed liquid state provides some advantages, including in situ activation of the acoustic signal, longer circulation persistence, and the advent of expanded diagnostic and therapeutic applications in pathologies which exhibit compromised vasculature. One obstacle to clinical translation is the inability of the limited surfactant present on the nanodrop to encapsulate the greatly expanded microbubble interface, resulting in ephemeral microbubbles with limited utility. In this study, we examine a biomimetic approach to stabilize an expanding gas surface by employing the lung surfactant replacement, beractant. Lung surfactant contains a suite of lipids and proteins that provide efficient shuttling of material from bilayer folds to the monolayer surface. We hypothesized that beractant would improve stability of acoustically vaporized microbubbles. To test this hypothesis, we characterized beractant surface dilation mechanics and revealed a novel biophysical phenomenon of rapid interfacial melting, spreading, and resolidification. We then harnessed this unique functionality to increase the stability and echogenicity of microbubbles produced after acoustic droplet vaporization for in vivo ultrasound imaging. Such biomimetic lung surfactant-stabilized nanodrops may be useful for applications in ultrasound imaging and therapy.
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Affiliation(s)
- Alec N Thomas
- Department of Mechanical Engineering, University of Colorado, Boulder 80309, Colorado, United States
- Institute of Biomedical Engineering, Oxford University, Oxford OX3 7DQ, U.K
| | - Kang-Ho Song
- Department of Mechanical Engineering, University of Colorado, Boulder 80309, Colorado, United States
| | - Awaneesh Upadhyay
- Department of Mechanical Engineering, University of Colorado, Boulder 80309, Colorado, United States
| | - Virginie Papadopoulou
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill & North Carolina State University, Chapel Hill 27514, North Carolina, United States
| | - David Ramirez
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder 80045, Colorado, United States
| | - Richard K P Benninger
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder 80045, Colorado, United States
| | - Matthew Lowerison
- Department of Electrical and Computer Engineering, University of Illinois, Urbana-Champaign 61801, Colorado, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign 61801, Colorado, United States
| | - Pengfei Song
- Department of Electrical and Computer Engineering, University of Illinois, Urbana-Champaign 61801, Colorado, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign 61801, Colorado, United States
| | - Todd W Murray
- Department of Mechanical Engineering, University of Colorado, Boulder 80309, Colorado, United States
- Department of Biomedical Engineering, University of Colorado, Boulder 80309, Colorado, United States
| | - Mark A Borden
- Department of Mechanical Engineering, University of Colorado, Boulder 80309, Colorado, United States
- Department of Biomedical Engineering, University of Colorado, Boulder 80309, Colorado, United States
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11
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The Impact of Lipid Handling and Phase Distribution on the Acoustic Behavior of Microbubbles. Pharmaceutics 2021; 13:pharmaceutics13010119. [PMID: 33477843 PMCID: PMC7832861 DOI: 10.3390/pharmaceutics13010119] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/20/2022] Open
Abstract
Phospholipid-coated microbubbles are ultrasound contrast agents that can be employed for ultrasound molecular imaging and drug delivery. For safe and effective implementation, microbubbles must respond uniformly and predictably to ultrasound. Therefore, we investigated how lipid handling and phase distribution affected the variability in the acoustic behavior of microbubbles. Cholesterol was used to modify the lateral molecular packing of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)-based microbubbles. To assess the effect of lipid handling, microbubbles were produced by a direct method, i.e., lipids directly dispersed in an aqueous medium or indirect method, i.e., lipids first dissolved in an organic solvent. The lipid phase and ligand distribution in the microbubble coating were investigated using confocal microscopy, and the acoustic response was recorded with the Brandaris 128 ultra-high-speed camera. In microbubbles with 12 mol% cholesterol, the lipids were miscible and all in the same phase, which resulted in more buckle formation, lower shell elasticity and higher shell viscosity. Indirect DSPC microbubbles had a more uniform response to ultrasound than direct DSPC and indirect DSPC-cholesterol microbubbles. The difference in lipid handling between direct and indirect DSPC microbubbles significantly affected the acoustic behavior. Indirect DSPC microbubbles are the most promising candidate for ultrasound molecular imaging and drug delivery applications.
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12
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13
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Supponen O, Upadhyay A, Lum J, Guidi F, Murray T, Vos HJ, Tortoli P, Borden M. The effect of size range on ultrasound-induced translations in microbubble populations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:3236. [PMID: 32486824 PMCID: PMC7205472 DOI: 10.1121/10.0001172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/17/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Microbubble translations driven by ultrasound-induced radiation forces can be beneficial for applications in ultrasound molecular imaging and drug delivery. Here, the effect of size range in microbubble populations on their translations is investigated experimentally and theoretically. The displacements within five distinct size-isolated microbubble populations are driven by a standard ultrasound-imaging probe at frequencies ranging from 3 to 7 MHz, and measured using the multi-gate spectral Doppler approach. Peak microbubble displacements, reaching up to 10 μm per pulse, are found to describe transient phenomena from the resonant proportion of each bubble population. The overall trend of the statistical behavior of the bubble displacements, quantified by the total number of identified displacements, reveals significant differences between the bubble populations as a function of the transmission frequency. A good agreement is found between the experiments and theory that includes a model parameter fit, which is further supported by separate measurements of individual microbubbles to characterize the viscoelasticity of their stabilizing lipid shell. These findings may help to tune the microbubble size distribution and ultrasound transmission parameters to optimize the radiation-force translations. They also demonstrate a simple technique to characterize the microbubble shell viscosity, the fitted model parameter, from freely floating microbubble populations using a standard ultrasound-imaging probe.
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Affiliation(s)
- Outi Supponen
- Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
| | - Awaneesh Upadhyay
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, Colorado 80309, USA
| | - Jordan Lum
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, Colorado 80309, USA
| | - Francesco Guidi
- Department of Information Engineering, University of Florence, Via di S. Marta 3, 50139 Florence, Italy
| | - Todd Murray
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, Colorado 80309, USA
| | - Hendrik J. Vos
- Department of Biomedical Engineering, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Piero Tortoli
- Department of Information Engineering, University of Florence, Via di S. Marta 3, 50139 Florence, Italy
| | - Mark Borden
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, Colorado 80309, USA
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14
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Ilhan-Ayisigi E, Saglam-Metiner P, Manzi G, Giannasi K, van Hoeve W, Yesil-Celiktas O. One-Step Microfluidic Coating of Phospholipid Microbubbles with Natural Alginate Polymer as a Delivery System for Human Epithelial Lung Adenocarcinoma. Macromol Biosci 2020; 20:e2000084. [PMID: 32346989 DOI: 10.1002/mabi.202000084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 03/24/2020] [Indexed: 12/14/2022]
Abstract
In this study, the neoplastic drug frequently used in the treatment of lung cancer, carboplatin is loaded to microbubbles via a microfluidic platform. In order to increase the drug loading capacity of microbubbles, carboplatin is encapsulated into alginate polymer layer. The phospholipid microbubbles (MBs) are synthesized by MicroSphere Creator, which is connected with T-junction and micromixer for the treatment with CaCl2 solution to provide gelation of the alginate coated phospholipid microbubbles (AMBs). The carboplatin loaded alginate coated phospholipid microbubbles (CAMBs) result in 12.2 ± 0.21 µm mean size, obtained by mixing with 0.05% CaCl2 using T-junction. The cytotoxic activities of the synthesized MBs, AMBs, and CAMBs are also investigated with the 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) (MTT) and live/dead fluorescent dying assays in the A549 and BEAS-2B cell lines. The one-step microfluidic coating of lipid microbubbles with natural alginate polymer appears to be a promising strategy for enhanced drug reservoir properties.
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Affiliation(s)
- Esra Ilhan-Ayisigi
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova-Izmir, 35100, Turkey.,Genetic and Bioengineering Department, Faculty of Engineering and Architecture, Ahi Evran University, Kirsehir, 40100, Turkey.,Tide Microfluidics B.V., Capitool 41, Enschede, 7521 PL, The Netherlands
| | - Pelin Saglam-Metiner
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova-Izmir, 35100, Turkey
| | - Giuliana Manzi
- Tide Microfluidics B.V., Capitool 41, Enschede, 7521 PL, The Netherlands
| | - Katharine Giannasi
- Tide Microfluidics B.V., Capitool 41, Enschede, 7521 PL, The Netherlands
| | - Wim van Hoeve
- Tide Microfluidics B.V., Capitool 41, Enschede, 7521 PL, The Netherlands
| | - Ozlem Yesil-Celiktas
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova-Izmir, 35100, Turkey
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15
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Lum JS, Daeichin V, Kienle DF, Schwartz DK, Murray TW, Borden MA. Changes in microbubble dynamics upon adhesion to a solid surface. APPLIED PHYSICS LETTERS 2020; 116:123703. [PMID: 32231399 PMCID: PMC7093207 DOI: 10.1063/1.5135017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
The interaction between an acoustically driven microbubble and a surface is of interest for a variety of applications, such as ultrasound imaging and therapy. Prior investigations have mainly focused on acoustic effects of a rigid boundary, where it was generally observed that the wall increases inertia and reduces the microbubble resonance frequency. Here we investigate the response of a lipid-coated microbubble adherent to a rigid wall. Firm adhesion between the microbubble and a glass surface was achieved through either specific (biotin/avidin) or nonspecific (lipid/glass) interactions. Total internal reflection fluorescence microscopy was used to verify conditions leading to either adhesion or non-adhesion of the bubble to a glass or rigid polymer surface. Individual microbubbles were driven acoustically to sub-nanometer-scale radial oscillations using a photoacoustic technique. Remarkably, adherent microbubbles were shown to have a higher resonance frequency than non-adherent microbubbles resting against the wall. Analysis of the resonance curves indicates that adhesion stiffens the bubble by an apparent increase in the shell elasticity term and decrease in the shell viscosity. Based on these results, we conclude that surface adhesion is dominant over acoustic effects for low-amplitude microbubble oscillations.
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Affiliation(s)
- Jordan S. Lum
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | | | - Daniel F. Kienle
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Daniel K. Schwartz
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | | | - Mark A. Borden
- Author to whom correspondence should be addressed:. Tel.: 303.492.7750
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16
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Borden MA. Intermolecular Forces Model for Lipid Microbubble Shells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10042-10051. [PMID: 30543753 DOI: 10.1021/acs.langmuir.8b03641] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lipid-coated microbubbles are currently used clinically as ultrasound contrast agents for echocardiography and radiology and are being developed for many new diagnostic and therapeutic applications. Accordingly, there is a growing need to engineer specific formulations by employing rational design to guide lipid selection and processing. This approach requires a quantitative relationship between lipid chemistry and interfacial properties of the microbubble shell. Just such a model is proposed here on the basis of lateral Coulomb and van der Waals interactions between lipid head- and tailgroups, using previous coarse graining and force fields developed for molecular dynamics simulations. The model predicts with sufficient accuracy the monolayer permeability, the elasticity as a function of either lipid composition or temperature, and the equilibrium spreading surface tension of the lipid onto an air/water interface. In the future, the intermolecular forces model could be employed to elucidate more complex phenomena and to engineer novel microbubble formulations.
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Affiliation(s)
- Mark Andrew Borden
- Mechanical Engineering , University of Colorado , Boulder , Colorado 80309-0427 , United States
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17
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Helfield B. A Review of Phospholipid Encapsulated Ultrasound Contrast Agent Microbubble Physics. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:282-300. [PMID: 30413335 DOI: 10.1016/j.ultrasmedbio.2018.09.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/11/2018] [Accepted: 09/20/2018] [Indexed: 06/08/2023]
Abstract
Ultrasound contrast agent microbubbles have expanded the utility of biomedical ultrasound from anatomic imaging to the assessment of microvascular blood flow characteristics and ultrasound-assisted therapeutic applications. Central to their effectiveness in these applications is their resonant and non-linear oscillation behaviour. This article reviews the salient physics of an oscillating microbubble in an ultrasound field, with particular emphasis on phospholipid-coated agents. Both the theoretical underpinnings of bubble vibration and the experimental evidence of non-linear encapsulated bubble dynamics and scattering are discussed and placed within the context of current and emerging applications.
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Affiliation(s)
- Brandon Helfield
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
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18
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Segers T, Gaud E, Versluis M, Frinking P. High-precision acoustic measurements of the nonlinear dilatational elasticity of phospholipid coated monodisperse microbubbles. SOFT MATTER 2018; 14:9550-9561. [PMID: 30357244 DOI: 10.1039/c8sm00918j] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The acoustic response of phospholipid-coated microbubble ultrasound contrast agents (UCA) is dramatically affected by their stabilizing shell. The interfacial shell elasticity increases the resonance frequency, the shell viscosity increases damping, and the nonlinear shell viscoelasticity increases the generation of harmonic echoes that are routinely used in contrast-enhanced ultrasound imaging. To date, the surface area-dependent interfacial properties of the phospholipid coating have never been measured due to the extremely short time scales of the MHz frequencies at which the microscopic bubbles are driven. Here, we present high-precision acoustic measurements of the dilatational nonlinear viscoelastic shell properties of phospholipid-coated microbubbles. These highly accurate measurements are now accessible for the first time by tuning the surface dilatation, that is, the lipid packing density, of well-controlled monodisperse bubble suspensions through the ambient pressure. Upon compression, the shell elasticity of bubbles coated with DPPC and DPPE-PEG5000 was found to increase up to an elasticity of 0.6 N m-1 after which the monolayer collapses and the elasticity vanishes. During bubble expansion, the elasticity drops monotonically in two stages, first to an elasticity of 0.35 N m-1, and then more rapidly to zero. Integration of the elasticity vs. surface area curves showed that, indeed, a phospholipid-coated microbubble is in a tensionless state upon compression, and that it reaches the interfacial tension of the surrounding medium upon expansion. The measurements presented in this work reveal the detailed features of the nonlinear dilatational shell behavior of micron-sized lipid-coated bubbles.
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Affiliation(s)
- Tim Segers
- Bracco Suisse S.A., Route de la Galaise 31, 1228 Geneva, Switzerland.
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19
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Pellow C, Acconcia C, Zheng G, Goertz DE. Threshold-dependent nonlinear scattering from porphyrin nanobubbles for vascular and extravascular applications. ACTA ACUST UNITED AC 2018; 63:215001. [DOI: 10.1088/1361-6560/aae571] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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