The micro total analysis system (μTAS) has seen great interest and advances since its definition over two decades ago. By harnessing the fabrication tools of the semiconductor industry and exploiting the unique physical phenomena that dominate at the micro- to nano-scale, these devices aim to address applications ranging from point-of-care diagnostics to pharmaceutical development. A truly versatile μTAS technology platform will enable reconfigurable, parallel, and high resolution analysis, processing, and sorting/purification. To this end, we present the concept of light-induced electrokinetics, which enables the patterning of electric fields using low-intensity light. This platform allows for the manipulation of both fluids (optoelectrowetting (OEW)) and particles (optoelectronic tweezers (OET)) over a featureless substrate. In this work, we will discuss three examples of how this technology demonstrates each of the μTAS requirements. Specifically, we will use this platform to assess the developmental potential of preimplantation-stage embryos, perform high throughput light-induced electroporation of single cells, and, finally, demonstrate the ability to unify the OET and OEW device enabling both droplet and particle manipulation on a single device. Within the context of these examples, the potential of light-induced electrokinetics as a generic μTAS platform is elucidated.

The authors demonstrate an optical manipulation mechanism of gas bubbles for microfluidic applications. Air bubbles in a silicone oil medium are manipulated via thermocapillary forces generated by the absorption of a laser in an amorphous silicon thin film. In contrast to previous demonstrations of optically controlled thermally driven bubble movement, transparent liquids can be used, as the thermal gradient is formed from laser absorption in the amorphous silicon substrate, and not in the liquid. A variety of bubbles with volumes ranging from 19 pl to 23 nl was transported at measured velocities of up to 1.5 mm/s.