Discovery Seminar - Chemical Engineering Department
Professor David Fernandez Rivas, University of Twente
Title : “Ballistic Microfluidics as a platform for Chemical Engineering Applications and Bioengineering”
Abstract :
Our team has developed the BuBble Gun platform to accelerate small liquid volumes with utilization potential in biomedical applications and chemical processes. We have organized the work along three main testing frameworks:
1) Cavitation: the actuation is done with pulsed and continuous wave lasers, where the absorption of the optical energy by a liquid contained in a microchannel lead to an explosively growing bubble. Besides advanced heat transfer studies including additives such as nanoparticles, we are investigating ultrafast contact line dynamics.
2) Jetting: the growing bubble displaces the liquid in the microchannel, resulting in fast traveling droplets that can stretch into jets. The channel geometry and internal coatings influences the jet breakup, the resulting drop size distribution, the trajectory of the jet, and the consistency of jetting across trials.
3) Impact: we have studied jet impacts onto e.g., hydrogels and skin with precise control over volumes (pL to mL) and penetration depths (µm to mm), without changing the microfludic device, by varying parameters such as laser power, beam diameter and filling level of the liquid container. We perform numerical and experimental studies of the fluid dynamics, including the transition from capillary-dominated cavity closure to gas-pressure-dominated closure at higher Weber numbers. We have made also progress in needle-free injection into ex vivo human skin.
Each of these three frameworks offers advantages for manipulating viscous forces, surface tension, thermal gradients, and mass transport. We initiated experiments to demonstrate the ability of microjets to increase the mixing inside droplets. Lastly, we extend our studies on electrolysis at the microscale with the BuBble Gun, with the purpose of controlling mixing, enhance mass transport and to better understand the influence of overpotentials and gaseous bubble formation in the efficiency of electrochemical systems.
Biography:
David Fernandez Rivas (BS: 2004; MSc: 2006 Nuclear Engineering, Higher Institute of Science and Technology, InSTEC, Havana, Cuba) obtained his PhD at the University of Twente UT (2012). Assistant professor (2014-2019), associate professor (2020-2021) and Professor (2021) in the Mesoscale Chemical Systems Group, UT. He is research affiliate at the Mechanical Engineering Department, Massachusetts Institute of Technology, USA (2017) and Visiting Professor at the Dermatology Department, Erasmus MC Hospital, Rotterdam, The Netherlands.
His research interest and expertise are in the areas of microfluidics, transdermal drug delivery alternatives, solar-to-fuel cells, process intensification, acoustic cavitation and sonochemistry. In 2019, he obtained the European Research Council Starting Grant for his project BuBble Gun, aimed at penetrating microjets in soft substrates, towards controlled needle-free injections. David received the prestigious VIDI grant, from the Dutch Research Council in 2023. He has received several recognitions, such as the Young Sonochemist Award, given by the Japan Society of Sonochemistry (JSS) in 2011, the Pieter Langerhuizen Lambertuszoon Fonds prize (2016) awarded by the Royal Holland Society of Sciences and Humanities (KHMW), and elected as Engineer of the Year 2021, and the Prince Friso Award by the Royal Dutch Institute of Engineers (KIVI). His work in Public Outreach earned him the Stairways to Impact Award, granted by the Dutch Scientific Council, and the UT in the Media Award, both in 2021. He was elected to the Global Young Academy (2020) and the Young Academy Europe (2020), elected Secretary in 2023. In 2024, David was installed at the De Jonge Akademie (Dutch Young Academy), Royal Netherlands Academy of Arts and Sciences.
David has co-authored over 60 reviewed journal papers and wrote the book Empathic Entrepreneurial Engineering. He is inventor of a patent commercialized by the spin-off BuBclean (2013) of which he is cofounder. He also founded FlowBeams, a spin-off from the University of Twente (2021) to valorize his research and second patent on needle-free injections. He was co-chair of the COST Action Greenering: Green Chemical Engineering Network towards upscaling sustainable processes, from the European Cooperation in Science & Technology (2019-2022). He also serves in the editorial board of several journals, such as Ultrasonics Sonochemistry, and Biomicrofluidics.
