Synthesis and 3D Printing of PEG–Poly(propylene fumarate) Diblock and Triblock Copolymer Hydrogels

PEG-based hydrogels are used widely in exploratory tissue engineering applications but in general lack chemical and structural diversity. Additive manufacturing offers pathways to otherwise unattainable scaffold morphologies but has been applied sparingly to cross-linked hydrogels. Herein, monomethyl ether poly­(ethylene glycol) (PEG) and PEG–diol were used to initiate the ring-opening copolymerization (ROCOP) of maleic anhydride and propylene oxide to yield well-defined diblock and triblock copolymers of PEG–poly­(propylene maleate) (PPM) and ultimately PEG-poly­(propylene fumarate) (PPF) with different molecular mass PEG macroinitiators and block length ratios. Using continuous digital light processing (cDLP), hydrogels were photochemically printed from an aqueous solution which resulted in a 10-fold increase in elongation at break compared to traditional diethyl fumarate (DEF) based printing. Furthermore, PPF–PEG–PPF triblock hydrogels were also found to be biocompatible in vitro across a number of engineered MC3T3, NIH3T3, and primary Schwann cells.