Setting mechanism of a new injectable Dicalcium Phosphate Dihydrate (DCPD) forming cement.

We previously described the gelation mechanism of calcium polyphosphate (CPP) in the presence of water. In this study, we developed novel and injectable poly-dicalcium phosphate dihydrate (P-DCPD) forming cement by the reaction of acidic CPP gel with alkali tetracalcium phosphate (TTCP). The setting reaction mechanism of P-DCPD is due to the intermolecular interaction between CPP gel and TTCP that was supported by XRD, AFM, Raman spectra analysis and SEM. The setting mechanism of P-DCPD is completely different from the classical calcium phosphate cement (CPC) that achieves crystallization by monophosphates reaction. P-DCPD represents a new type of poly-CPCs with significant advantages, including strong mechanical strength, excellent cohesion and easy of handling. More extensive experiments are currently underway to further evaluate the performance of P-DCPD cements, including biocompatibility, degradation behavior and bone defect hearing efficacy, among others.