In-vitro apatite formation on phosphorylated bamboo.

Natural self-reinforced composite, bamboo, was surface modified by phosphorylation with urea-H3PO4 and NaOH-H3PO4 methods; then precalcification was performed by immersing samples in saturated Ca(OH)2 solution. After that, calcium phosphate can be formed on the surface of bamboo samples in calcification media: simulated body fluid (1.5 SBF) and accelerated calcification solution (ACS). Experimental results reveal that pre-calcification is an inevitable step for the formation of calcium phosphate. The calcium phosphate formed in 1.5 SBF was identified by thin-film X-ray diffraction as apatite which was not well crystallized. Compared with the urea-H3PO4 method, the NaOH-H3PO4 method has the advantages of quicker and continuous apatite formation and stronger adhesive between apatite and bamboo.