Review on polyphosphazenes-based materials for bone and skeleton tissue engineering

The skeleton performs motley of functions. Defected bones and metameric loss of bone are often resulted due to innate abnormalities and accidental injuries. An assessment is made on the diversity of chemistry of phosphazene with an inflection on new developments and their importance in tissue engineering. Tissue engineering mostly uses polymers that can biodegrade in porous/permeable scaffolds form for treating damaged tissues and skeleton. Demand of these polymers is increasing as timely substrates for tissue regeneration in contrast to the mostly used polyethylene terephalate, polyorthoesters, and poly(α-amino acids). Polyphosphazenes as biodegradable polymers have great potential for applications of tissue engineering. Due to biodegradability of P–N backbone, vast diversity of structure and high functional density polyphosphazenes provides many advantages for the formation of biologically compatible macromolecules. However, the nature of the side group determines the degradation ability of such polymers. These biodegradable polymers (polyphosphazenes) provide harmless and pH neutral substances because phosphates and ammonia have high buffer capacity. This review article focuses on the biocompatible polyphosphazenes and their utilization as regeneration of tissues, skeleton, and bones with a particular focus on materials that contains only polyphosphazenes, blends of polyphosphazene, and composites made from polyphosphazene.