In Vitro Biocompatibility of Diazirine-Grafted Biomaterials

Photoactivation of aryl-diazirines is an emerging method of rapid, covalent crosslinking under ambient conditions. These attributes make those compounds candidates for grafting onto inert polymer backbones in order to produce stimuli-sensitive biomaterials. However, no risk assessments are available to gauge the toxicity of the leachable components after crosslinking activation. Herein, a stimuli-sensitive biomaterial is formulated from diazirine-grafted polycaprolactone tetrol. Also known as CaproGlu, this biomaterial undergoes UVA-activated crosslinking, with many positive attributes toward bioadhesive applications; hydrophobic, solvent-free, liquid at room temperature, and transitions into a foam biorubber after mild UVA illumination. As a model diazirine-grafted biomaterial, hydrolyzed CaproGlu leachates are evaluated for genotoxicity and skin sensitization, namely, Ames test, direct peptide reactivity, and ARE-Nrf2 luciferase assays. The degradation products of diazirine-mediated crosslinking observe little to no risk of in vitro genotoxicity or skin sensitization.