Controlled network structures of chitosan-poly(ethylene glycol) hydrogel microspheres and their impact on protein conjugation

Abstract

We demonstrate a facile approach to manufacture hydrogel microspheres with controlled and macroporous network structures via a simple yet versatile micromolding-based technique. Specifically, highly uniform poly(ethylene glycol) (PEG) hydrogel microspheres containing chemically functional chitosan are readily fabricated using the micromolding-based technique that utilizes surface tension-induced droplet formation of aqueous prepolymer solution followed by photo-induced interfacial polymerization. Network structures of the hydrogel microspheres are readily controlled by simple addition of inert porogen, which induces phase separation during the polymerization. Fluorescent labeling studies reveal tunable distribution of the chitosan within the PEG networks (i.e., uniform and core-shell like distributions) depending on the content of the porogen in the prepolymer solution. In addition, protein conjugation studies show tunable pore sizes and 3D network structures by adjusting content of the porogen, and formation of macroporous networks leading to significantly improved protein conjugation kinetics. The macroporous network structures are further supported with scanning electron microscopy (SEM) results that correspond well with confocal microscopy results. We believe that our fabrication strategy offers a simple and robust route to construct diverse 3D hydrogel network structures with chemical functionality, enabling production of a variety of biofunctionalized hydrogel microspheres that can be utilized in various biomedical applications.