Structural engineering of polyurethanes for biomedical applications

Polyurethane, a synthetic polymer distinguished by its urethane (carbamate, -NHCOO-) and/or urea (-NHCONH-) linkages, has been applied in various industries since its discovery in 1937 by Bayer and colleagues. The successful in vivo use of segmented multiblock thermoplastic polyurethane in 1967 marked the beginning of its development for biomedical applications. Over the past few decades, research on polyurethane biomaterials has evolved from focusing on biostable to biodegradable forms, exploring multifunctionality and application in areas like functional medical devices, tissue engineering scaffolds, drug delivery systems, etc. This review aims to summarize the recent advancements in engineering polyurethane structures for biomedical applications, presenting the main methods utilized in their preparation, biological functions, and their main biomedical applications. In addition, we proposed four general strategies for engineering polyurethane structures in the biomedical field, offering a structured methodology for researchers and engineers engaged in polyurethane biomaterials work. Concluding the review, we spotlight future development directions, emphasizing multifunctional programmable polyurethane, peptide-mimicking polyurethane, and poly (hydroxyl urethane).