On-chip manipulation and sensing of microorganisms by magnetically driven microtools with a force sensing structure

In this paper, we introduce an untethered type of magnetically driven microtool (MMT) with a force sensing function to investigate the stimulus characteristics of aquatic microorganisms in a microfluidic chip. The microchip is composed of the proposed MMTs, which have a Si-Ni hybrid structure, a transparent cover made of polydimethylsiloxane (PDMS), a glass substrate, and a microspacer to prevent both friction during the force measurement and damage to the micropattern of the MMT. The fabrication and drive performance of the MMT, which is actuated by permanent magnets from the outside of the microchip, verified in basic experiments. Finally, we succeeded in on-chip manipulation and sensing of microorganisms using this MMT, which we found to be easy to use.