Exploring Thiol-Yne Based Monomers as Low Cytotoxic Building Blocks for Radical Photopolymerization

The last decade has seen a remarkable interest in the development of biocompatible monomers for the realization of patient specific medical devices by means of UV-based additive manufacturing technologies. This contribution deals with the synthesis and investigation of novel thiol-yne based monomers with a focus on their biocompatibility and also the mechanical properties in their cured state. It could be successfully shown that propargyl and but-1-yne-4-yl ether derivatives have a significant lower cytotoxicity than the corresponding (meth)acrylates with similar backbones. Together with appropriate thiol monomers, these compounds show reactivities in the range of (meth)acrylates and almost quantitative triple bond conversions. A particular highlight is the investigation of the network properties of photo cured alkynyl ether/thiol resins by means of low field solid state nuclear magnetic resonance spectroscopy. Additionally, dynamic mechanical analysis of those polymers revealed that monomers containing rigid backbones lead to moduli and glass transition temperatures (Tg's), sufficiently high for the fabrication of medical devices by UV based additive manufacturing methods.