Fatty-acid-derived ester-urethane macromonomers synthesized using bismuth and zinc catalysts

Injectable and photocurable macromonomers synthesized using a heterometallic magnesium-titanium metal-organic catalyst for elastomeric polymer networks

Injectable and in situ photocurable biomaterials are receiving a lot of attention due to their ease of application via syringe or dedicated applicator and ability to be used in laparoscopic and robotic minimally invasive procedures. The aim of this work was to synthesize photocurable ester-urethane macromonomers using a heterometallic magnesium-titanium catalyst, magnesium-titanium(iv) butoxide for elastomeric polymer networks. The progress of the two-step synthesis of macromonomers was monitored using infrared spectroscopy. The chemical structure and molecular weight of the obtained macromonomers were characterized using nuclear magnetic resonance spectroscopy and gel permeation chromatography. The dynamic viscosity of the obtained macromonomers was evaluated by a rheometer. Next, the photocuring process was studied under both air and argon atmospheres. Both the thermal and dynamic mechanical thermal properties of the photocured soft and elastomeric networks were investigated. Finally, in vitro cytotoxicity screening of polymer networks based on ISO10993-5 revealed high cell viability (over 77%) regardless of curing atmosphere. Overall, our results indicate that this heterometallic magnesium-titanium butoxide catalyst can be an attractive alternative to commonly used homometallic catalysts for the synthesis of injectable and photocurable materials for medical applications.

Bio-Based Photoreversible Networks Containing Coumarin Groups for Future Medical Applications

Photocurable biomaterials that can be delivered as liquids and rapidly (within seconds) cured in situ using UV light are gaining increased interest in advanced medical applications. Nowadays, fabrication of biomaterials that contain organic photosensitive compounds have become popular due to their self-crosslinking and versatile abilities of changing shape or dissolving upon external stimuli. Special attention is paid to coumarin due to its excellent photo- and thermoreactivity upon UV light irradiation. Thus, by modifying the structure of coumarin to make it reactive with a bio-based fatty acid dimer derivative, we specifically designed a dynamic network that is sensitive to UV light and able to both crosslink and re-crosslink upon variable wave lengths. A simple condensation reaction was applied to obtain future biomaterial suitable for injection and photocrosslinking in situ upon UV light exposure and decrosslinking at the same external stimuli but at different wave lengths. Thus, we performed the modification of 7-hydroxycoumarin and condensation with fatty acid dimer derivatives towards a photoreversible bio-based network for future medical applications.