High speed microrobot actuation in a microfluidic chip by levitated structure with riblet surface

This paper presents the high speed microrobot actuation driven by permanent magnets in a microfluidic chip. The riblet surface, which is regularly arrayed V groove reduces the fluid friction and enables stable actuation in high speed. The comprehensive analysis of fluid force, the optimum design and its fabrication were conducted and proved the friction reduction by riblet. The Ni and Si composite fabrication was employed to form the optimum riblet shape on the microrobot surface by wet and dry etching. The evaluation experiments show the microrobot can actuate up to 90 Hs, which is 10 times higher than the original microrobot. In addition, it can be applied to cell manipulation without harm since the microrobot is covered by Si, which is bio-compatible. One of the applications of developed microrobot was demonstrated by assembling cell aggregation in high speed.