Microgels On Demand

Most methods for forming hydrogels result in a collection of materials that have the same composition and aren’t individually addressable. To add flexibility to the fabrication method, Aaron R. Wheeler, Irwin A. Eydelnant, and Bingyu Betty Li of the University of Toronto have used a digital microfluidic system to make arrays of individually addressable hydrogel microparticles—so-called microgels—with arbitrary shape and composition (Nat. Commun. 2014, DOI: 10.1038/ncomms4355). In digital microfluidics, reagent-filled droplets are manipulated on an open surface by applying electrical potentials to underlying electrodes. Wheeler and coworkers dispensed droplets of various gel-forming materials on the device surface to make particles with controllable shapes and compositions. The researchers used the arrays for the three-dimensional cell culture of kidney cells, which they kept alive for five days by periodically adding droplets of culture media to select microgel particles. “This work represents a significant advance in the fabrication and utility of microgel arrays,” says MIT’s Patrick A. Doyle, who also develops microparticle synthesis methods. “I see the work having a strong impact on the field of tissue engineering.”