Biodegradable Polyphosphazenes for Biomedical Applications

Polyphosphazenes are an important class of biodegradable polymers with immense biomedical potential. These polymers consist of an inorganic backbone of -P = N- repeating units and variable organic side groups. Inorganic-organic hybrid polyphosphazenes project an ensemble of interesting properties such as biocompatibility, unique degradation behaviour with metabolizable by-products, easy synthesis and chemical modifications, and variable physical and chemical properties, which makes them interesting candidates for regenerative engineering, drug delivery, bioresorbable sutures, bioimaging, coatings, etc. to name a few. This review discusses polyphosphazene synthesis and chemistry, in vitro and in vivo biocompatibility, and degradation behaviour, and summarizes the biomedical advances made using polyphosphazenes in the last few decades. Lay Summary Polymers play a very important role in our daily lives. In the last few decades, polymers are being considered for different biomedical applications like resorbable sutures and degradable implants. Polyphosphazenes are a unique class of biodegradable polymers whose degradation by-products that can be easily absorbed by our bodies. This review introduces polyphosphazene synthesis and its properties and gives an overview of the different biomedical applications for which these polymers have been explored.