Biodegradable functional biomaterials exploiting substituted trimethylene carbonates and organocatalytic transesterification

Biodegradable aliphatic carbonyl polymers, such as polylactides, polylactones and polycarbonates, have been studied for application in a broad range of resorbable medical devices. With progress in diagnostic and therapeutic technologies for an aging society, the demand for diverse and highly developed biodegradable biomaterials has increased. A combination of heterocyclic monomers with functional substituents and complex macromolecular architecture has been proposed as a means to produce multifunctional biodegradable polymers. This review mainly highlights the synthesis and application of poly(trimethylene carbonate) (PTMC) analogs with various substituents derived from 2,2-bis(methylol) propionic acid. In addition, organocatalytic transesterification is discussed as an indispensable tool for further functionalization and sophistication of the PTMC analogs. Metal-free controlled polymerization allows for both the safer production of biomedical devices and the precise formation of complex macromolecular structures. The organocatalytic depolymerization of engineering polyesters has also been exploited to efficiently produce valuable aromatic terephthalamides that, in turn, can be used to extend the functionality of PTMC analogs such as mesogen-like motifs. Finally, the use of supramolecular chemistry for further multi-functionalization and hydration-based improvement of biocompatibility is briefly discussed.