Attinger D. – TechConnect Briefs

Generation of picoliter and nanoliter drops on-demand in a microfluidic chip

Xu J., Attinger D., Columbia University, US

In this work, we introduce the novel technique of in-chip drop-on-demand, which consists in dispensing picoliter to nanoliter drops on demand directly in the liquid-filled channels of a polymer microfluidic chip. The technique involves a [...]

Ultrasound-driven viscous streaming, modelled via momentum injection

Packer J., Attinger D., Ventikos Y., University of Oxford, UK

Mixing, particle transport, and lysis of biological cells can be performed in microfluidic chips by actuators based on the controlled motion of a gas-liquid interface. There is strong motivation to develop practical and tractable computational [...]

Modeling evaporation and ring-shaped particle deposition of a colloidal microdroplet, with applications in biological assays

Bhardwaj R., Attinger D., Columbia University, US

Colloidal drops evaporating on a solid substrate can be used as vehicles for dispensing or organizing small particles suspended within them. The pattern left after evaporation can be a ring-like structure such as the dried [...]

A Bio-Inspired Rotor Powered by a Micro-Bubble

Kao J., Warren J., Xu J., Attinger D., Columbia University, US

We present and characterize a novel micro-rotor actuation concept, where acoustic oscillations of a micro-bubble produce a steady fluid flow driving a microfabricated rotor at a rotating speed as high as 600 rpm. Developing micro-machines [...]

On the Motion of a Bubble through Microchannel Contractions

Chio H., Jensen M.J., Wang X., Bruus H., Attinger D., Columbia University, US

We present the first transient pressure measurements and high-speed visualizations of a gas bubble passing through liquid-filled microchannel contractions. Results are compared with a simple theoretical model taking into account the Young-Laplace pressure drop, the [...]

Clogging Pressures of Bubbles in Microchannel Contractions: Theory and Experiments

Jensen M.J., Wang X., Attinger D., Bruus H., Mikroelektronik Centret, DTU, DK

We present a theoretical, numerical, and experimental study of bubbles passing through a microchannel contraction. A certain pressure, the so-called clogging pressure, is needed to push a bubble through a microchannel contraction. We present the [...]