Publications
77 results found
Achakulwisut K, Tam C, Huerre A, et al., 2017, Stability of clay particle-coated microbubbles in alkanes against dissolution induced by heating, Langmuir, Vol: 33, Pages: 3809-3817, ISSN: 1520-5827
We investigated the dissolution and morphological dynamics of air bubbles in alkanes stabilized by fluorinated colloidal clay particles when subjected to temperature changes. A model for bubble dissolution with time-dependent temperature reveals that increasing the temperature enhances the bubble dissolution rate in alkanes, opposite to the behavior in water, because of the differing trends in gas solubility. Experimental results for uncoated air bubbles in decane and hexadecane confirm this prediction. Clay-coated bubbles in decane and hexadecane are shown to be stable in air-saturated oil at constant temperature, where dissolution is driven mainly by the Laplace pressure. When the temperature increases from ambient, the particle-coated bubbles are prone to dissolution as the oil phase becomes undersaturated. The interfacial layer of particles is observed to undergo buckling and crumpling, without shedding of clay particles. Increasing the concentration of particles is shown to enhance the bubble stability by providing a higher resistance to dissolution. When subjected to complex temperature cycles, for which the effect of time-dependent temperature is dominant, the clay-coated bubbles can resist long-term dissolution in conditions under which uncoated bubbles dissolve completely. These results underpin the design of ultrastable oil foams stabilized by solid particles with improved shelf life under changing environmental conditions.
Pouliopoulos A, Caiqin L, Tinguely M, et al., 2016, Rapid short-pulse sequences enhance the spatiotemporal uniformity of acoustically driven microbubble activity during flow conditions, Journal of the Acoustical Society of America, Vol: 140, ISSN: 0001-4966
Despite the promise of microbubble-mediated focused ultrasound therapies, in vivo findings have revealed over-treated and under-treated regions distributed throughout the focal volume. This poor distribution cannot be improved by conventional pulse shapes and sequences, due to their limited ability to control acoustic cavitation dynamics within the ultrasonic focus. This paper describes the design of a rapid short-pulse (RaSP) sequence which is comprised of short pulses separated by μs off-time intervals. Improved acoustic cavitation distribution was based on the hypothesis that microbubbles can freely move during the pulse off-times. Flowing SonoVue® microbubbles (flow velocity: 10 mm/s) were sonicated with a 0.5 MHz focused ultrasound transducer using RaSP sequences (peak-rarefactional pressures: 146–900 kPa, pulse repetition frequency: 1.25 kHz, and pulse lengths: 5–50 cycles). The distribution of cavitation activity was evaluated using passive acoustic mapping. RaSP sequences generated uniform distributions within the focus in contrast to long pulses (50 000 cycles) that produced non-uniform distributions. Fast microbubble destruction occurred for long pulses, whereas microbubble activity was sustained for longer durations for shorter pulses. High-speed microscopy revealed increased mobility in the direction of flow during RaSP sonication. In conclusion, RaSP sequences produced spatiotemporally uniform cavitation distributions and could result in efficient therapies by spreading cavitation throughout the treatment area.
Poulichet V, Huerre A, Garbin V, 2016, Shape oscillations of particle-coated bubbles and directional particle expulsion, Soft Matter, Vol: 13, Pages: 125-133, ISSN: 1744-6848
Bubbles stabilised by colloidal particles can find applications in advanced materials, catalysis anddrug delivery. For applications in controlled release, it is desirable to remove the particles fromthe interface in a programmable fashion. We have previously shown that ultrasound waves excitevolumetric oscillations of particle-coated bubbles, resulting in precisely timed particle expulsiondue to interface compression on a ultrafast timescale [Poulichet et al., Proc. Natl. Acad. Sci.USA, 2015, 112, 5932]. We also observed shape oscillations, which were found to drive directionalparticle expulsion from the antinodes of the non-spherical deformation. In this paper weinvestigate the mechanisms leading to directional particle expulsion during shape oscillations ofparticle-coated bubbles driven by ultrasound at 40 kHz. We perform high-speed visualisation ofthe interface shape and of the particle distribution during ultrafast deformation at a rate of upto 105 s−1. The mode of shape oscillations is found to not depend on the bubble size, in contrastwith what has been reported for uncoated bubbles. A decomposition of the non-sphericalshape in spatial Fourier modes reveals that the interplay of different modes determines the locationsof particle expulsion. The n-fold symmetry of the dominant mode does not always leadto desorption from all 2n antinodes, but only those where there is favourable alignment with thesub-dominant modes. Desorption from the antinodes of the shape oscillations is due to different,concurrent mechanisms. The radial acceleration of the interface at the antinodes can be upto 105 − 106 ms−2, hence there is a contribution from the inertia of the particles localised at theantinodes. In addition, we found that particles migrate to the antinodes of the shape oscillation,thereby enhancing the contribution from the surface pressure in the monolayer.
Udoh C, Garbin V, Cabral JP, 2016, Microporous polymer particles via phase inversion in microfluidics: impact of non-solvent quality, Langmuir, Vol: 32, Pages: 8131-8140, ISSN: 0743-7463
We investigate the impact of ternary phase behavior on the microstructure of porous polymer particles produced by solvent extraction of polymer solution droplets by a nonsolvent. Microfluidic devices fabricated by frontal photopolymerization are employed to produce monodisperse polymer (P)/solvent (S) droplets suspended in a carrier (C) phase before inducing solvent extraction by precipitation in a nonsolvent (NS) bath. Model systems of sodium poly(styrenesulfonate) (P), water (S), hexadecane (C), and either methyl ethyl ketone (MEK) or ethyl acetate (EA) as NS are selected. Extraction across the liquid–liquid interface results in a decrease in the droplet radius and also an ingress of nonsolvent, leading to droplet phase demixing and coarsening. As the concentration of the polymer-rich phase increases, droplet shrinkage and solvent exchange slow down and eventually cease, resulting in microporous polymer particles (of radius ≃50–200 μm) with a smooth surface. The internal structure of these capsules, with pore sizes of ≃1–100 μm, is found to be controlled by polymer solution thermodynamics and the extraction pathway. The ternary phase diagrams are measured by turbidimetry, and the kinetics of phase separation is estimated by stopped-flow small-angle neutron scattering. The higher solubility of water in MEK results in faster particle-formation kinetics than in EA. Surprisingly, however, the lower polymer miscibility with EA/water results in a deeper quench inside the phase boundary and small phase sizes, thus yielding particles with small pores (of narrow distribution). The effects of droplet size, polymer content, and nonsolvent quality provide comprehensive insight into porous particle and capsule formation by phase inversion, with a range of practical applications.
Tinguely M, Hennessy MG, Pommella A, et al., 2016, Surface waves on a soft viscoelastic layer produced by an oscillating microbubble, Soft Matter, Vol: 12, Pages: 4247-4256, ISSN: 1744-6848
Ultrasound-driven bubbles can cause significant deformation of soft viscoelastic layers, for instance in surface cleaning and biomedical applications. The effect of the viscoelastic properties of a boundary on the bubble–boundary interaction has been explored only qualitatively, and remains poorly understood. We investigate the dynamic deformation of a viscoelastic layer induced by the volumetric oscillations of an ultrasound-driven microbubble. High-speed video microscopy is used to observe the deformation produced by a bubble oscillating at 17–20 kHz in contact with the surface of a hydrogel. The localised oscillating pressure applied by the bubble generates surface elastic (Rayleigh) waves on the gel, characterised by elliptical particle trajectories. The tilt angle of the elliptical trajectories varies with increasing distance from the bubble. Unexpectedly, the direction of rotation of the surface elements on the elliptical trajectories shifts from prograde to retrograde at a distance from the bubble that depends on the viscoelastic properties of the gel. To explain these behaviours, we develop a simple three-dimensional model for the deformation of a viscoelastic solid by a localised oscillating force. By using as input for the model the values of the shear modulus obtained from the propagation velocity of the Rayleigh waves, we find good qualitative agreement with the experimental observations.
Tinguely M, Matar OK, Garbin V, 2015, Tracking the deformation of a tissue phantom induced by ultrasound-driven bubble oscillations, 9th International Symposium on Cavitation (CAV2015), Publisher: IOP Publishing Ltd, ISSN: 1742-6588
Poulichet V, Garbin V, 2015, Cooling particle-coated bubbles: destabilization beyond dissolution arrest, Langmuir, Vol: 31, Pages: 12035-12042, ISSN: 1520-5827
Emulsions and foams that remain stable under varying environmental conditions are central in the food, personal care, and other formulated products industries. Foams stabilized by solid particles can provide longer-term stability than surfactant-stabilized foams. This stability is partly ascribed to the observation that solid particles can arrest bubble dissolution, which is driven by the Laplace pressure across the curved gas–liquid interface. We studied experimentally the effect of changes in temperature on the lifetime of particle-coated air microbubbles in water. We found that a decrease in temperature destabilizes particle-coated microbubbles beyond dissolution arrest. A quasi-steady model describing the effect of the change in temperature on mass transfer suggests that the dominant mechanism of destabilization is the increased solubility of the gas in the liquid, leading to a condition of undersaturation. Experiments at constant temperature confirmed that undersaturation alone can drive destabilization of particle-coated bubbles, even for vanishing Laplace pressure. We also found that dissolution of a particle-coated bubble can lead either to buckling of the coating or to gradual expulsion of particles, depending on the particle-to-bubble size ratio, with potential implications for controlled release.
Ja'afar F, Leow CH, Garbin V, et al., 2015, Surface Charge Measurement of SonoVue, Definity and Optison: A Comparison of Laser Doppler Electrophoresis and Micro-Electrophoresis, Ultrasound in Medicine and Biology, Vol: 41, Pages: 2990-3000, ISSN: 0301-5629
Microbubble (MB) contrast-enhanced ultrasonography is a promising tool for targeted molecular imaging. It is important to determine the MB surface charge accurately as it affects the MB interactions with cell membranes. In this article, we report the surface charge measurement of SonoVue, Definity and Optison. We compare the performance of the widely used laser Doppler electrophoresis with an in-house micro-electrophoresis system. By optically tracking MB electrophoretic velocity in a microchannel, we determined the zeta potentials of MB samples. Using micro-electrophoresis, we obtained zeta potential values for SonoVue, Definity and Optison of −28.3, −4.2 and −9.5 mV, with relative standard deviations of 5%, 48% and 8%, respectively. In comparison, laser Doppler electrophoresis gave −8.7, +0.7 and +15.8 mV with relative standard deviations of 330%, 29,000% and 130%, respectively. We found that the reliability of laser Doppler electrophoresis is compromised by MB buoyancy. Micro-electrophoresis determined zeta potential values with a 10-fold improvement in relative standard deviation.
Pommella A, Brooks NJ, Seddon JM, et al., 2015, Selective flow-induced vesicle rupture to sort by membrane mechanical properties, Scientific Reports, Vol: 5, ISSN: 2045-2322
Garbin V, Jenkins I, Sinno T, et al., 2015, Erratum: Interactions and Stress Relaxation in Monolayers of Soft Nanoparticles at Fluid-Fluid Interfaces (Physical Review Letters (2015) 114:108301), Physical Review Letters, Vol: 115, ISSN: 0031-9007
Poulichet V, Garbin V, 2015, Ultrafast desorption of colloidal particles from fluid interfaces, Proceedings of the National Academy of Sciences, Vol: 112, Pages: 5932-5937, ISSN: 1091-6490
The self-assembly of solid particles at fluid-fluid interfaces is widely exploited to stabilize emulsions and foams, and in materials synthesis. The self-assembly mechanism is very robust owing to the large capillary energy associated with particle adsorption, of the order of millions of times the thermal energy for micrometer-sized colloids. The microstructure of the interfacial colloid monolayer can also favor stability, for instance in the case of particle-stabilized bubbles, which can be indefinitely stable against dissolution due to jamming of the colloid monolayer. As a result, significant challenges arise when destabilization and particle removal are a requirement. Here we demonstrate ultrafast desorption of colloid monolayers from the interface of particle-stabilized bubbles. We drive the bubbles into periodic compression-expansion using ultrasound waves, causing significant deformation and microstructural changes in the particle monolayer. Using high-speed microscopy we uncover different particle expulsion scenarios depending on the mode of bubble deformation, including highly directional patterns of particle release during shape oscillations. Complete removal of colloid monolayers from bubbles is achieved in under a millisecond. Our method should find a broad range of applications, from nanoparticle recycling in sustainable processes to programmable particle delivery in lab-on-a-chip applications.
Garbin V, 2015, Remotely triggered colloidal disassembly from particle-laden microbubble, Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Garbin V, Jenkins I, Sinno T, et al., 2015, Interactions and stress relaxation in monolayers of soft nanoparticles at fluid-fluid interfaces, Physical Review Letters, Vol: 114, ISSN: 0031-9007
Pommella A, Lantz J, Poulichet V, et al., 2013, High-frequency capillary waves excited by oscillating microbubbles
This fluid dynamics video shows high-frequency capillary waves excited by thevolumetric oscillations of microbubbles near a free surface. The frequency ofthe capillary waves is controlled by the oscillation frequency of themicrobubbles, which are driven by an ultrasound field. Radial capillary wavesproduced by single bubbles and interference patterns generated by thesuperposition of capillary waves from multiple bubbles are shown.
Garbin V, 2013, Colloidal particles: Surfactants with a difference, Physics Today, Vol: 66, Pages: 68-69, ISSN: 0031-9228
Yao L, Botto L, Cavallaro M, et al., 2013, Near field capillary repulsion, Soft Matter, Vol: 9, Pages: 779-786
Kokhuis TJA, Garbin V, Kooiman K, et al., 2013, SECONDARY BJERKNES FORCES DEFORM TARGETED MICROBUBBLES, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 39, Pages: 490-506, ISSN: 0301-5629
- Author Web Link
- Cite
- Citations: 32
Garbin V, Crocker JC, Stebe KJ, 2012, Nanoparticles at fluid interfaces: Exploiting capping ligands to control adsorption, stability and dynamics, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 387, Pages: 1-11, ISSN: 0021-9797
- Author Web Link
- Cite
- Citations: 155
Garbin V, Crocker JC, Stebe KJ, 2012, Forced desorption of nanoparticles from an oil-water interface, 11th International Biorelated Polymer Symposium / 243rd National Spring Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Garbin V, Crocker JC, Stebe KJ, 2012, Forced Desorption of Nanoparticles from an Oil-Water Interface, LANGMUIR, Vol: 28, Pages: 1663-1667, ISSN: 0743-7463
- Author Web Link
- Open Access Link
- Cite
- Citations: 83
Garbin V, Overvelde M, Dollet B, et al., 2011, Unbinding of targeted ultrasound contrast agent microbubbles by secondary acoustic forces, PHYSICS IN MEDICINE AND BIOLOGY, Vol: 56, Pages: 6161-6177, ISSN: 0031-9155
- Author Web Link
- Cite
- Citations: 36
Overvelde M, Garbin V, Dollet B, et al., 2011, DYNAMICS OF COATED MICROBUBBLES ADHERENT TO A WALL, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 37, Pages: 1500-1508, ISSN: 0301-5629
- Author Web Link
- Cite
- Citations: 53
Stebe KJ, Garbin V, Crocker J, 2011, Ligand-mediated repulsion enables nanoparticle desorption from compressed oil-water interfaces, 242nd National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Aubin-Tam M-E, Appleyard DC, Ferrari E, et al., 2011, Adhesion through Single Peptide Aptamers, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 115, Pages: 3657-3664, ISSN: 1089-5639
- Author Web Link
- Cite
- Citations: 16
Sijl J, Overvelde M, Dollet B, et al., 2011, "Compression-only" behavior: A second-order nonlinear response of ultrasound contrast agent microbubbles, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 129, Pages: 1729-1739, ISSN: 0001-4966
- Author Web Link
- Cite
- Citations: 61
Kokhuis TJA, Garbin V, Kooiman K, et al., 2011, Probing microbubble adhesion using secondary acoustic radiation force, IEEE International Ultrasonics Symposium (IUS), Publisher: IEEE, Pages: 947-950, ISSN: 1948-5719
- Author Web Link
- Cite
- Citations: 1
Overvelde M, Garbin V, Sijl J, et al., 2010, NONLINEAR SHELL BEHAVIOR OF PHOSPHOLIPID-COATED MICROBUBBLES, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 36, Pages: 2080-2092, ISSN: 0301-5629
- Author Web Link
- Cite
- Citations: 133
Sijl J, Dollet B, Overvelde M, et al., 2010, Subharmonic behavior of phospholipid-coated ultrasound contrast agent microbubbles, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 128, Pages: 3239-3252, ISSN: 0001-4966
- Author Web Link
- Cite
- Citations: 91
Lewandowski EP, Cavallaro M, Botto L, et al., 2010, Orientation and Self-Assembly of Cylindrical Particles by Anisotropic Capillary Interactions, LANGMUIR, Vol: 26, Pages: 15142-15154, ISSN: 0743-7463
- Author Web Link
- Cite
- Citations: 141
Aubin-Tam M-E, Appleyard DC, Garbin V, et al., 2010, Single Molecule Force Spectroscopy of Peptide Aptamers, Publisher: CELL PRESS, Pages: 617A-618A, ISSN: 0006-3495
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.