Thermally stable, photocrossinkable and biocompatible copolymers for melt electrowriting

Melt electrowriting (MEW) is capable of generating highly defined microarchitectures suitable for tissue engineering applications. The main biodegradable polymer typically utilized for MEW processing, poly(ϵ-caprolactone), is prone to creep under dynamic loads and plasticization due to water absorption, making its use problematic for situations demanding dynamic loading in aqueous media. Photocrosslinking during processing can eliminate these problems while also allowing for manipulation of mechanical properties. However, photocrosslinking strategies utilized to date have either limited processing time or require prolonged UV irradiation. Herein we demonstrate the potential of a cyclic trimethylene carbonate monomer bearing a pendant coumarin moiety (MUM) for creating MEW processable copolymers that are thermally stable and photocrosslinkable. The MUM was copolymerized with caprolactone to form copolymers that were MEW processed into both linear and crimped fiber structures followed by long-wave UV photocrosslinking yielding high modulus scaffolds with very low sol content. The photocrosslinked scaffolds were also cytocompatible. The ability to copolymerize MUM with other cyclic lactone monomers allows for the generation of a variety of MEW processable polymers with tunable properties. Collectively, the findings demonstrate the potential of MUM containing copolymers for MEW generation of scaffolds for a range of tissue engineering applications.