Ionic Polymerization-Based\nSynthesis of Bioinspired\nAdhesive Hydrogel Microparticles with Tunable Morphologies from Microfluidics

Abstract

Shape-anisotropic hydrogel microparticles have attracted\nconsiderable\nattention for drug-delivery applications. Particularly, nonspherical\nhydrogel microcarriers with enhanced adhesive and circulatory abilities\nhave demonstrated value in gastrointestinal drug administration. Herein,\ninspired by the structures of natural suckers, we demonstrate an ionic\npolymerization-based production of calcium (Ca)-alginate microparticles\nwith tunable shapes from Janus emulsion for the first time. Monodispersed\nJanus droplets composed of sodium alginate and nongelable segments\nwere generated using a coflow droplet generator. The interfacial curvatures,\nsizes, and production frequencies of Janus droplets can be flexibly\ncontrolled by varying the flow conditions and surfactant concentrations\nin the multiphase system. Janus droplets were ionically solidified\non a chip, and hydrogel beads of different shapes were obtained. The\nin vitro and in vivo adhesion abilities of the hydrogel beads to the\nmouse colon were investigated. The anisotropic beads showed prominent\nadhesive properties compared with the spherical particles owing to\ntheir sticky hydrogel components and unique shapes. Finally, a novel\ncomputational fluid dynamics and discrete element method (CFD-DEM)\ncoupling simulation was used to evaluate particle migration and contact\nforces theoretically. This review presents a simple strategy to synthesize\nCa-alginate particles with tunable structures that could be ideal\nmaterials for constructing gastrointestinal drug delivery systems.