Directly photopatterning of polycaprolactone-derived photocured resin by UV-initiated thiol-ene “click” reaction: Enhanced mechanical property and excellent biocompatibility

This paper reports a novel routine for the fabrication of a polycaprolactone-derived (PCL-derived) photocured material cross-linked by pentaerythritol tetra (PETMP) with enhanced mechanical property and excellent biocompatibility. The photocured material is cross-linked via UV irradiation through thiol-ene “click” chemistry. The main novelty of this technique is the facile fabrication of high-resolution patterns (∼5 μm) using photolithography, and without adding photo-initiators. The photocured material is studied regarding to its thermal property, mechanical property and cytocompatibility. DSC and DMA suggest that the flexibility and toughness of PCL-derived photocured material have improved. Accordingly, the PCL-derived photocured material achieves enhanced mechanical property (with the increase of PCL segment content from 0 to 38.0%, the photocured samples monotonically increased their breaking strength from 0.62 to 3.10 MPa and Young's modulus from 1.39 to 9.22 MPa). Due to the incorporation of the PCL-derived copolymer, the material shows excellent affinity to cells, which is demonstrated by the cell proliferation and release of LDH. The hemolysis ratio of PCL-derived photocured materials is all <5%, while the PEGDA photocured material is ∼17%. It can also be observed that PCL-derived photocured material will improve the biocompatibility and reduce biotoxicity compared with PEGDA. This facile route for synthesis of biocompatible photocured resin with micrometer-resolute patterns has a good impact in bioengineering and biomedical fields.