PRODUCTION OF EXTREMELY-SMALL HYDROGEL MICROSPHERES BY UTILIZING WATER-DROPLET DISSOLUTION IN A POLAR SOLVENT

In this study, we demonstrated a new method to produce extremely small hydrogel beads by utilizing water-droplet dissolution in a weak polar solvent. Water droplets containing hydrogel polymer were generated in the continuous phase of the solvent, and water was dissolved from the droplets to the continuous phase while the hydrogel polymer was concentrated. The concentrated droplets were then gelled, forming hydrogel beads significantly smaller than the initial droplet size. We employed methyl acetate as the solvent, having a high solubility of water (8%), and successfully produced Ca-alginate and chitosan microbeads with sizes smaller than 10 ∝m.