Enhancing the mechanical properties and physical stability of biomimetic polymer hydrogels for micro-patterning and tissue engineering applications

Abstract

Low mechanical strength and rapid degradation of photo-crosslinkable polymers are the major obstacles for their applications. The aim of this study was to address these issues by fabricating hybrid polymeric hydrogels from a biopolymer (gelatin) and a synthetic polymer. Methacrylated gelatin (GelMA) and poly(lactic-ethylene oxide fumarate) (PLEOF) were photo-crosslinked, using Irgacure and poly(ethylene glycol)-diacrylate. The optimum hybrid hydrogel was produced when using 200mg/ml PLEOF and 100mg/ml GelMA. These hydrogels possessed porosity in the range of 90%, also comprised of micro (∼20μm) and macro pores (540μm), which are suitable for nutrients mass transfer and osteoblast cell proliferation, respectively. The compression modulus of GelMA-PLEOF hydrogels was more than 200kPa, which is paramount compared to GelMA hydrogels. Moreover, fabrication of hybrid hydrogel substantially enhanced the structural stability of gelatin in simulated physiological environment from one week to more than 28days. In vitro studies showed that primary human osteoblast cells adhered and proliferated into PLEOF/GelMA hydrogel. Additionally, micro-patterns with 10×100μm dimensions were created on the surface of these hydrogels to promote the cellular alignment. These results demonstrated the potential of using this hybrid construct for in vitro regeneration of load-bearing tissues.