A Novel Approach to Prepare Nano-Hydroxyapatite / Silk Fibroin Composite to Increase Nucleation Sites

A composite of needle-like nano-Hydroxyapatite / silk fibroin (n-HA/SF) with strong interfacial bonding was successfully prepared from calcium chloride (CaCl2) and diammonium phosphate ((NH4)2HPO4) as starting materials of HA in the presence of SF powders dissolved in a ternary solvent system of CaCl2-C2H5OH-H2O (1:2:8 in molar ration) at 80 °C for 30 min prior to preparation of n-HA/SF composite. The n-HA crystals in the composite were poorly crystallized and uniformly distributed in the composite with a crystal size of 4~6 nm in diameter and 20~40 nm in length, which was smaller than that of pure nano-HA. Molecular interaction and strong chemical bonds were formed between n-HA and SF in the composite, which were revealed by Fourier transform infrared spectrometric analysis (FTIR). The synthetic n-HA/SF composite had a good homogeneity and preferential orientation along c-axis and would have a great potential for bone tissue engineering.