Photocurable Crosslinker from Bio-Based Non-Isocyanate Poly(hydroxyurethane) for Biocompatible Hydrogels

This study explores the synthesis of photocurable non-isocyanate polyhydroxyethylurethanes (BPHUs) derived from renewable sources, designed for biomedical applications and the development towards advanced light curing processes. The following two pathways were developed: an aliphatic route using 1,4-butanediol-derived cyclic carbonates and an aromatic route with resorcinol-based carbonates. Ring-opening polymerization with dodecanediamine produced BPHU intermediates, which were methacrylated to form photoreactive derivatives (aliphatic MAs and aromatic MAs). Comprehensive characterization, including NMR, GPC, and FTIR, confirmed the successful synthesis. The UV curing of these methacrylated compounds yielded hydrogels with swelling properties. Aliphatic BPHUs achieved a gel content of 91.3% and a swelling of 1057%, demonstrating the flexibility and UV stability suitable for adaptable biomedical applications. Conversely, aromatic BPHUs displayed a gel content of 78.1% and a swelling of 3304%, indicating higher rigidity, which is advantageous for load-bearing uses. Cytotoxicity assessments adhering to the DIN EN ISO 10993-5 standard demonstrated non-cytotoxicity, with an >80% cell viability for both variants. This research underscores the potential of green chemistry in crafting biocompatible, versatile BPHUs, paving the way for eco-friendly materials in implantable medical devices.