Comparative study of visible light polymerized gelatin hydrogels for 3D culture of hepatic progenitor cells

Abstract

ABSTRACT Photopolymerization techniques have been widely used to create hydrogels for biomedical applications. Visible light‐based photopolymerizations are commonly initiated by type II (i.e., noncleavage‐type) photoinitiator in conjunction with a coinitiator. On the other hand, type I photoinitiators (i.e., cleavage type) are rarely compatible with visible light‐based initiation due to their limited molar absorbability in the visible light wavelengths. Here, we report visible light initiated orthogonal photoclick crosslinking to fabricate gelatin‐norbornene and poly(ethylene glycol)‐tetra‐thiol hydrogels using either cleavage‐type (i.e., lithium acylphosphinate, LAP) or noncleavage‐type photoinitiator (i.e., eosin‐Y, EY) without the use of a coinitiator. Regardless of the initiator type, the step‐growth gelatin‐PEG hybrid hydrogels crosslinked and degraded similarly. While both systems exhibited similar cytocompatibility for hepatic progenitor HepaRG cells, gelation initiated by noncleavage‐type initiator EY afforded slightly higher degree of hepatic gene expression. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44585.