Fabricating Biodegradable Tissue Scaffolds Through a New Aggregation Triggered Physical Cross-Linking Strategy of Hydrophilic and Hydrophobic Polymers

Abstract

In the study, a new strategy is presented to make PLGA (poly lactic-co-glycolic acid) and POEGMEMA (poly(oligo(ethylene glycol) methyl ether methacrylate)) based biodegradable and biocompatible tissue scaffold via a new physical cross-linking method. The advantage of brushed structure of POEGMEMA polymer and the hydrophobic character of PLGA polymer is taken to make physically entangled network in aqueous media. The hydrophobic nature of PLGA allows to get scaffolds even at low ratio of PLGA (25%, w/w) when using POEGMEMA (yield: 86%). This strategy gives robust polymeric networks in aqueous media without using chemical reactions through high hydrophilic polymer content. Scaffolds with high POEGMEMA ratio (75%, w/w) show two times higher water uptake ratio (approximate to 300%) and two times lower compression strength (19 kPa) compared to the ones with lower POEGMEMA content (50%, w/w). They also show desired degradation profiles in various aqueous solutions. While the scaffolds prepared with 25% and 50% PLGA are almost stable in first 20 days, they completely degrade in 40-50 days. Both scaffold formulations (25% PLGA-75% POEGMEMA and 50% PLGA-50% POEGMEMA) have similar proliferative properties for fibroblast cells. The scaffolds also do not show toxicity compared to control group according to live-dead assay. Taking the advantage of hydrophobic nature of PLGA and branched structure of POEGMEMA, enables to get physically cross-linked scaffolds. Physical cross-linking is achieved by aggregation of PLGA in aqueous media and formation of intra- and inter-molecular entangles between aggregated PLGA and branched POEGMEMA polymers. Thus, though high hydrophilic POEGMEMA content, robust polymeric scaffolds are obtained without using toxic reactions. image