Fig. 5From: Preparation of alginate hydrogel microparticles by gelation introducing cross-linkers using droplet-based microfluidics: a review of methodsImage of connected knots formed after mixing Na-alginate and CaCl2 solutions in mineral oil with surfactant, in a PDMS-based microfluidic chip. Figure reprinted with permission from Reference [60]. Copyright 2006 American Chemical SocietyBack to article page