Opto-fluidically multiplexed assembly and micro-robotics

Abstract

Techniques for high-definition micromanipulations, such as optical tweezers, hold substantial interest across a wide range of disciplines. However, their applicability remains constrained by material properties and laser exposure. And while microfluidic manipulations have been suggested as an alternative, their inherent capabilities are limited and further hindered by practical challenges of implementation and control. Here we show that the iterative application of laser-induced, localized flow fields can be used for the relative positioning of multiple micro-particles, irrespectively of their material properties. Compared to the standing theoretical proposal, our method keeps particles mobile, and we show that their precision manipulation is non-linearly accelerated via the multiplexing of temperature stimuli below the heat diffusion limit. The resulting flow fields are topologically rich and mathematically predictable. They represent unprecedented microfluidic control capabilities that are illustrated by the actuation of humanoid micro-robots with up to 30 degrees of freedom, whose motions are sufficiently well-defined to reliably communicate personal characteristics such as gender, happiness and nervousness. Our results constitute high-definition micro-fluidic manipulations with transformative potential for assembly, micro-manufacturing, the life sciences, robotics and opto-hydraulically actuated micro-factories.

Light-deformable microrobots shape up for the biological obstacle course

“…Precise optogenetic activation of individual cells requires the control of high spatial frequencies of light that may be maintained within shallow (~100 µm) sections, which could be further extended with promising adaptive optics approaches 12 . Interestingly, indirect optical trapping through opto-fluidic streaming was also recently demonstrated in Light, Science & Applications , overcoming issues with trapping instability 13 . Much deeper, millimeter-deep control could be achieved in the optically diffuse regime if the collective behavior of microrobots can be statistically predicted and controlled.…”