UV-curable, 3D printable and biocompatible silicone elastomers

A biocompatible silicone elastomer that can be UV-cured and 3D printed via thiol-ene photopolymerization between vinyl and thiol functionalized polysiloxanes is explored in this study. The in-situ photo-rheology demonstrates that the photo-crosslinking of silicone elastomer occurs instantaneously upon exposure to UV radiation and its gelation time is influenced synergically by thiol-ene molar ratio, photoinitiator dosage and UV irradiation intensity. Differential scanning photo-calorimeter results indicate that UV-initiated thiol-ene photoreaction preferably follows a second-order reaction kinetics and its activation energy is approximately 23.3 kJ/mol. Moreover, antibacterial assay shows thiol-ene UV-cured silicone elastomer can inhibit the growth of Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria to some extent. Cytotoxicity and biocompatibility results reveal that this silicone elastomer also has good biocompatibility, and it used as wound dressing is conducive to the recovery of wounds. Furthermore, due to excellent spatiotemporal controllability of thiol-ene photoreaction, various elaborate architectures are fabricated by photo-patterning. On the other hand, this UV-curable formulation can also be 3D printed into various structures with smooth surface and good accuracy. These results propose that thiol-ene UV-curable silicone elastomer will be a promising material in biomedical applications as wound dressings or customized soft tissue scaffolds through 3D printing.