Comprehensive study of Inorganic Polyphosphates for Biomedical Engineering applications

New and innovative materials and devices are needed to combat challenging clinical applications such as chronic bone infections and cancerous tumors that are difficult to eradicate, with many current biomaterials being adapted where possible or applied sub-optimally to meet these needs. Our research program investigates whether a group of materials known as inorganic polyphosphates can be used to fill this critical role. ***Inorganic polyphosphates are long chains of phosphate molecules that can be formed into a variety of gels and glasses. Our previous research has shown that calcium polyphosphates have the potential to be used as drug delivery systems; drugs can be loaded into the calcium polyphosphate glass matrix as it forms into a gel and are later released as the matrix degrades. ***Two program streams are planned. In the first stream we will investigate the structure, composition and flow properties of polyphosphate gels and glasses made with sodium polyphosphates of different chain lengths in combination with different charged metal ions (such as calcium, strontium, and aluminum). We will examine as well the interaction of large, positively charged molecules (chitosan) with these polyphosphates to determine the processing conditions required for gelling. ***Based on the understanding gained from this research and from earlier observations, a second program stream will focus on transforming these inorganic polyphosphates into various forms, such as very small micro-beads and injectable materials having physical properties and drug delivery capability tailored to the particular treatment needs. A longer-term goal of this research is to investigate how new and advanced manufacturing processes such as electrospinning and 3-D printing might be used to create scaffolds made of inorganic polyphosphates. Such scaffolds would provide unique three-dimensional structures to direct cell attachment and growth in order to form new tissues. ***As inorganic polyphosphates play a role in many biological functions, including bone formation and blood clotting, and are also used in the manufacture of fire retardant materials and in many industrial applications such as environmental decontamination, advancing our basic understanding of inorganic polyphosphates and their manipulation through this proposed program of research may have implications beyond the development of new biomaterials and biomedical devices.**