Stereochemistry and stoichiometry in aliphatic polyester photopolymers for 3D printing tailored biomaterial scaffolds

Abstract

Stereoselective aliphatic polyesters were synthesized through the ring opening copolymerization of cyclic anhydrides and epoxides using a tin catalyst to yield M_n ∼ 10–13 kDa macromolecules (Đ < 1.6). Isomerization of the cis poly(maleate-co-phenyl glycidol ether) (PMPGE) to the trans isomer poly(fumarate-co-phenyl glycidol ether) (PFPGE) may be used to tune physical properties such as viscosity, which displays an order of magnitude increase as PMPFE is isomerized to PFPGE. However, the formulated photopolymer resins consisting of a 4-arm thiol and the polyester photopolymer display Newtonian fluid behavior and viscosities of ∼0.5 Pa s, ideal for digital light processing (DLP) 3D printing. Enhancement of the thermal, thermomechanical, mechanical, and gravimetric properties was achieved through off-stoichiometric imbalances in the photosets. For example, with a 20% excess of alkene both photopolymers display gelation times comparable with commercial resins (∼5 s) and were 3D printed via DLP into complex porous tissue scaffolds. Finally, cytocompatibility with murine macrophages over 7 days demonstrated superior material surfaces compared to control tissue culture polystyrene, as determined by statistically increased aspect ratios (cell spreading) and proliferation, indicating the biomedical application potential of these materials.