Outi Supponen

Last Name

Supponen

First Name

Outi

ORCID

0000-0001-6738-0675

Organisational unit

09708 - Supponen, Outi / Supponen, Outi

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Publications 1 - 10 of 38

Rebounds of deformed cavitation bubbles
Supponen, Outi; Obreschkow, Danail; Farhat, Mohamed (2018)
Physical Review Fluids
Cyclic jetting enables microbubble-mediated drug delivery
Cattaneo, Marco; Guerriero, Giulia; Shakya, Gazendra; et al. (2025)
Nature Physics
The pursuit of targeted therapies capable of overcoming biological barriers, including the blood-brain barrier, has spurred the investigation of stimuli-responsive microagents that can improve therapeutic efficacy and reduce undesirable side effects. Intravenously administered, ultrasound-responsive microbubbles are promising agents with demonstrated potential in clinical trials, but the mechanism underlying drug absorption remains unclear. Here we show that ultrasound-driven single microbubbles puncture the cell membrane and induce drug uptake through stable cyclic microjets. Our theoretical models successfully reproduce the observed bubble and cell dynamic responses. We find that cyclic jets arise from shape instabilities, as opposed to classical inertial jets that are driven by pressure gradients, enabling microjet formation at mild ultrasound pressures below 100 kPa. We also establish a threshold for bubble radial expansion beyond which microjets form and facilitate cellular permeation and show that the stress generated by microjetting outperforms previously suggested mechanisms by at least an order of magnitude. Overall, this work elucidates the physics behind microbubble-mediated targeted drug delivery and provides the criteria for its effective and safe application.
Impulse-driven release of gas-encapsulated drops
Bokman, Guillaume T.; Biasiori-Poulanges, Luc; Lukić, Bratislav; et al. (2024)
Journal of Fluid Mechanics
Gas-encapsulated drops, much like antibubbles, are drops enclosed in a bubble within a liquid. They show potential as payload carriers in fluid transport and mixing techniques where sound waves can be leveraged to induce the collapse of the gas core and the subsequent release of the drop. Here, the interaction of millimetre-sized gas-encapsulated drops with impulsive laser-induced shock waves is investigated to gain fundamental insights into the release process. Experimental synchrotron X-ray phase contrast imaging, which allows the drop dynamics to be visualised inside the encapsulating bubble, is complemented by numerical simulations to study the intricate physics at play. Three drop dynamical release regimes are discovered, namely the drop impact, partial deposition and jet impact regimes. The regime type is mainly dependent on the shape of the bubble interface impacting the drop and the associated Weber and Reynolds numbers. The drop dynamics of the drop impact and partial deposition regimes show similarities with the canonical configuration of drops impacting flat liquid surfaces, whereas the jet impact regime resembles binary drop collisions, which allows existing scaling laws to be applied to describe the underlying processes. The release of the drop is investigated numerically. The time evolution of the drop dissemination within the surrounding liquid discloses enhanced mixing for dynamics involving high Weber and Reynolds numbers such as the drop impact and jet impact regimes.
Jetting Behaviour of Ultrasound-driven Microbubbles in Contact with a Soft Substrate
Cattaneo, Marco; Shakya, Gazendra; Supponen, Outi (2023)
2023 IEEE International Ultrasonics Symposium (IUS)
The use of ultrasound-driven microbubbles presents a promising avenue for facilitating the localised delivery of therapeutics by inducing controlled nanodamage on capillary walls. Despite the tangible clinical evidence of the success of this approach, the underlying physical mechanism leading to nanodamage remains under debate. In this study, time-resolved side-view visualisations elucidate the interplay between soft substrates and microbubbles under clinically relevant ultrasound regimes. Our findings reveal the existence of four distinct regimes of bubble behaviour dependent on the bubble’s size and the role of shape deformations as governing mechanism for the bubble behaviour. Among these regimes, three result in the formation of periodic microjets. The remarkable speed of these microjets indicates their significant contribution in causing surface nanodamage.
The effect of size range on ultrasound-induced translations in microbubble populations
Supponen, Outi; Upadhyay, Awaneesh; Lum, Jordan; et al. (2020)
The Journal of the Acoustical Society of America
Detailed experiments on weakly deformed cavitation bubbles
Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; et al. (2019)
Experiments in Fluids
Synchrotron X-ray phase-contrast imaging of ultrasonic drop atomization
Prasanna, Anunay; Biasiori-Poulanges, Luc; Yu, Ya-Chi; et al. (2024)
International Journal of Multiphase Flow
Ultrasonic atomization is employed to generate size-controllable droplets for a variety of applications. Here, we minimize the number of parameters dictating the process by studying the atomization of a single drop pending from an ultrasonic horn. Spatiotemporally resolved X-ray phase-contrast imaging measurements show that the number-median sizes of the ejected droplets can be predicted by the linear Navier–Stokes equations, signifying that the size distribution is controlled by the fluid properties and the driving frequency. Experiments with larger pendant water drops indicate that the fluid–structure interaction plays a pivotal role in determining the ejection onset of the pendant drop. The atomization of viscoelastic drops is dictated by extended ligament formation, entrainment of air, and ejection of drop-encapsulated bubbles. Existing scaling laws are used to explain the required higher input amplitudes for the complete atomization of viscoelastic drops as compared to inviscid drops. Finally, we elucidate the differences between capillary wave-based and cavitation-based atomization and show that inducing cavitation and strong bubble oscillations quickens the onset of daughter drop ejection but impedes their size control.
The inner world of a collapsing bubble
Supponen, Outi; Kobel, Philippe; Obreschkow, Danail; et al. (2015)
Physics of Fluids
Synchrotron X-ray imaging of the onset of ultrasonic horn cavitation
Biasiori-Poulanges, Luc; Bourquard, Claire; Lukić, Bratislav; et al. (2023)
Ultrasonics Sonochemistry
High-power ultrasonic horns operating at low frequency are known to generate a cone-shaped cavitation bubble cloud beneath them. The exact physical processes resulting in the conical structure are still unclear mainly due to challenges associated with their visualization. Herein, we address the onset of the cavitation cloud by exploiting high-speed X-ray phase contrast imaging. It reveals that the cone formation is not immediate but results from a three-step phenomenology: (i) inception and oscillation of single bubbles, (ii) individual cloud formation under splitting or lens effects, and (iii) cloud merging leading to the formation of a bubble layer and, eventually, to the cone structure due to the radial pressure gradient on the horn tip.
Scaling laws for jets of single cavitation bubbles
Supponen, Outi; Obreschkow, Danail; Tinguely, Marc; et al. (2016)
Journal of Fluid Mechanics

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