Hydrolyzable and biocompatible aliphatic polycarbonates with ether-functionalized side chains attached via amide linkers

Abstract

Investigating polymer degradation mechanisms enables the establishment of controlled degradation techniques for the development of sustainable and recyclable materials. Hydration can play a crucial role in controlling the hydrolysis of polymers. Here, ether-functionalized aliphatic polycarbonates (APCs) susceptible to nonenzymatic hydrolysis were developed for application as biocompatible biomaterials. Among these polymers, those grafted with 2-methoxyethyl and 3-methoxypropyl side chains via an amide group were highly wettable, strongly interacted with water, and experienced almost complete hydrolysis in phosphate-buffered saline over 30 days, which was attributed to the hydrogen bonding between water and the amide/methoxy groups. In an alkaline medium, all amide-linked APCs were completely hydrolyzed within 30 days, regardless of the side-chain structure. In contrast, the nonamide-linked APCs and a representative aliphatic polycarbonate, poly(trimethylene carbonate), were minimally degraded in the buffer and experienced <31% degradation under alkaline conditions. The APC with the 3-methoxypropyl side chain exhibited platelet adhesion properties comparable to those of ether-functionalized APCs previously reported as blood-compatible polymers. Thus, our results demonstrate the effects of an amide linker on the hydration and hydrolytic properties of APCs and can help establish new design concepts for degradable polymers.