Spherical Calcium Alginate Microgels Synthesized Using a Microfluidic Chip

Abstract

Calcium alginate particles are usually generated by the cross-linking reaction between sodium alginate droplets and solution of divalent cations like CaCl2. The previous works using aqueous mixture solution as reactants would definitely induced the deformation of sodium alginate droplets and produce gel particles with un-uniform shapes. To solve this problem, here we present a method using CaCl2 emulsions as reactant. We fabricated a glass microfluidic chip consisting of two cross-shape junctions for generating Na-alginate droplets and cross-linking gelation respectively. We successfully produce gel particles using this device and also investigate the influential factors of CaCl2 emulsions on the gel particles′ shapes. Through controlling the properties of CaCl2 emulsions, we can generate calcium alginate particles with roundness over 0.95.