Amino Acid/calcium Phosphate Composite Material Preparation And Its Biocompatibility

Calcium phosphate (CP), the most important mineral in the body, has been paid a lot ofattentions in the fields of biomineralization and biomaterials. Controlled synthesize of CP crystalwith different morphology, structure and size is a hot issue due to their different bioactivity,biocompatibility and other physical-chemical properties. Recently, vital influence of organicmatrix on the formation of CP crystal in bone and tooth has been proved with more and moreevidences, but the detailed progress and mechanism for the formation of biominerals in vivo isunclear to this day. In this paper, nanometer-size CP crystals were prepared by a chemicalprecipitation method with L-Aspartate (L-Asp) and L-Serine (L-Ser) and L-Lysine (L-Lys) andL-Tyrosine (L-Tyr) as organic matrix, respectively. The products were characterized by X-raydiffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy., thermo gravimetricanalyzer(TGA), transmission electron microscopy (TEM), high Resolution transmissionelectron Microscopy(HRTEM), cell assay, etc. some results have been obtained as follows:1. The concentration of amino acid obviously affected morphologies of CP crystal. With theincrease of amino acid concentration, morphology of CP crystal changed from sheet-like tospindle-like in the presence of L-Asp, from irregular sheet-like to sheet-like in the presence ofL-Ser, from rod-like to spindle-like in the presence of L-Tyr and from needle-like to shuttle-likein the presence of L-Lys respectively.2. Different amino acids have a various influence on the size of CP crystal. The size of CPcrystals was similar to control in the presence of L-Asp or L-Ser, but the growth of CP crystalswas inhibited in the presence of L-Lys while promoted in the presence of L-Tyr.3. Effect of reaction time on the CP crystal formation was investigated at pH12and50℃.With the extension of reaction time, morphology of CP crystal changed from needle-like in theabsence of amino acid, from rod-like to spindle-like in the presence of L-Tyr and from sheet-liketo shuttle-like in the presence of L-Lys respectively.It was found that reaction time mainlyaffected samples in terms of size and shape.4. Obtained samples were cocultured with MG-63cells and then the morphology,proliferation and differentiation of cells were examined to evaluate biocompatibility of thematerials. Results showed that CP crystals obtained in the presence of L-Try and L-Lys holdbetter biocompatibility due to their higher ability to improve the differentiation and proliferation of cells, both of which had a huge potential for biomedical application.