Polythioesters

Polythioesters are a class of biodegradable and biocompatible polymers that incorporate both ester and thioester linkages in their repeating units. These materials have garnered significant interest in biomedical and environmental applications due to their tunable mechanical properties, degradability, and potential for controlled drug delivery.

The synthesis of polythioesters typically involves the condensation polymerization of diols with either thiol-functionalized dicarboxylic acids or dithiols with dicarboxylic acids. The resulting polymers often exhibit improved hydrolytic stability compared to traditional polyesters, owing to the presence of sulfur atoms in the backbone. This enhanced stability can be advantageous in applications requiring prolonged degradation times, such as long-term implants or sustained-release formulations.

Polythioesters can be designed with varying degrees of crystallinity, flexibility, and degradation rates by adjusting the monomer composition and molecular weight. Their biodegradability is primarily mediated by enzymatic hydrolysis, particularly by thiol-dependent esterases, which can cleave the thioester bonds under physiological conditions. This property makes them suitable for temporary medical devices, such as sutures or scaffolds for tissue engineering, where gradual resorption is desirable.

In addition to biomedical uses, polythioesters have been explored in eco-friendly packaging and biodegradable plastics due to their potential to replace petroleum-based polymers. Their synthesis often employs renewable feedstocks, further aligning with sustainable material development goals. However, challenges remain in optimizing their mechanical performance and ensuring consistent degradation rates for specific applications. Ongoing research continues to refine their synthesis, characterization, and functionalization to expand their utility in diverse fields.