Production of Functional Microtool Using Size-Classified Gel-Microbeads

In this study, we succeeded in producing functional microtool made of gel-microbead using size-dependent microparticle classification. Gel-microbead, which is used as the material for the microtool, is made by salting-out of hydrophilic photo-crosslinkable resin, ENT-3400. These gel-microbeads were separated according to their size by microfilters made of polydimethylsiloxane (PDMS). A first on is a row of fluidic micro-channels which block microbeads with a size over the width of the channel. Another filtering method has been experimented, using Magnetically driven MicroTool (MMT) to separate the beads using the centrifugal force created by this MMT actuated with a DC motor. Separated gel-microbeads were recovered after filtering step and then used to fabricate functional microtools, for example tether-shaped gel-tool, by contact to other gel-microbeads under UV illumination. Produced gel-tool is manipulated by optical tweezers in a microchip. We succeeded in getting size-dependent separation of the gel-microbeads and production of the tether-shaped gel-tool.