Paralleled microfluidic droplet generators on slits for mass-producing calcium-alginate microparticles

Abstract

Encapsulation of cells in calcium-alginate (Ca-alginate) hydrogels via droplet microfluidics has been popular for diverse biological applications. However, a limitation of a microfluidic droplet generator (MFDG) is its low throughput. Here, we propose a novel microfluidic platform to achieve the mass production of monodisperse Ca-alginate microgels encapsulating mammal cells. The microfluidic module consists of two distinct compartments: a polydimethylsiloxane (PDMS) microchip containing 16-128 paralleled rectangular microgrooves, and a cubic stainless-steel supporting module having four slits from which corn oil as a continuous phase, an aqueous sodium alginate solution as a disperse phase, and a water-in-oil emulsion phase containing calcium chloride solution are evenly supplied into the parallel and confined microchannels. We produced Ca-alginate hydrogel particles with diameters of 83 µm with a coefficient of variation around 5% at a maximum production rate of 406 s^-1.