(217eb) Chemically Triggered Degradable Poly(amides) for Biomaterial Applications

Degradable synthetic polymers are useful for applications such as drug delivery systems and tissue engineering scaffolds. In many such applications, it is important to control when and where the degradation of a polymer occurs. This has led to the development of materials that degrade when exposed to specific mechanistic triggers. One way to control polymer degradation is to incorporate a cleavable functionality that responds to a trigger that would normally be absent in the system of implementation. At present, there are very few examples of polymeric biomaterials with such features, and their applications are restricted because of issues related to accessibility and the nature of triggers. Here, we present the development of new chemically degradable poly(amides) by incorporating α-azido ether functional groups along the polymer backbone that can be cleaved in the presence of reducing agents such as dithiols and phosphines. Water-soluble and hydrophobic poly(amides) were synthesized and their physical properties were characterized. Chemically triggered degradation of the polymers was characterized using proton NMR spectroscopy, size exclusion chromatography, mass-loss studies and time-lapse photography. The degradation timescale of each polymer could be tuned by controlling the nature of the degrading trigger and its concentration. In principle, the triggered degradation method described here could be incorporated into biomedical materials where external control over polymer degradation is preferred.