Size-dependent microparticle filtration using magnetically driven microtool for producing gel-microtool

In this study, we successfully produced a functional microtool made of gel microbeads using size-dependent microparticle classification. Gel microbeads are made by salting-out hydrophilic photo-crosslinkable resin ENT-3400. These gel microbeads were separated according to their size using microfilters made of polydimethylsiloxane (PDMS). The first filter is a row of fluidic microchannels that block microbeads with a size greater than the channel's width. Another filtration method has been examined using a 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 filtration and used to fabricate functional microtools, for example, a tether-shaped gel tool, by contact with other gel microbeads under UV illumination. The produced gel tool is manipulated using optical tweezers in a microchip. We successfully achieved size-dependent separation of gel microbeads and production of a tether-shaped gel tool.