| Biomineralization is the forming process of biomineral with special advanced structure and assembly mode in the bio-system. During biomineralization, the self-assembly organic materials excreted by cells can act as templates for inorganic materials, inducing the formation of inorganic minerals with certain shape, size, orientation and structure. The main purpose of this study is to synthesize multi-shaped nano-hydroxyapatite (n-HA) as well as magnesium and titanium phosphate through biomimetic methods. The biomineralization mechanism was explored through characterizing the microstructures and properties of the samples.We introduced the nano-biomaterials and biotechnology in the paper. The studies and applications of n-HA at home and abroad were also analyzed, as well as some preparation methods. The multi-shaped n-HA particles were synthesized by using biomineralization method and the mechanism of biomineralization was further explored particularly.In the experimental section,various samples were synthesized through designing orthogonal experiments and choosing different conditions, such as, the variety of surfactants, the pH value of the solution, the time of biomineralization, the calcining temperature and the time of heat-preservation. The BET surface areas of the samples were measured to choose the best synthetic conditions. The results showed that the nano-powders with high BET surface areas were obtained when calcined at 300℃. At low pH value of 5.5-6.5, calcium phosphate materials with BET value at 100 m2 /g could be obtained by using ovalbumin as template. With the increase of pH value, its influence on the BET was lowed gradually. The bioactivity of the biosurfactant could be affected by the pH value of the solution greatly. It showed that the powders with high BET value of 129m~2/g could be obtained by using alkaloid as template which had higher activity in alkaline condition than ovalbumin and microbe. While using ovalbumin as template, the BET value was about 80m~2/g because of the short biomineralizing time and the high pH value. If given enough long biomineralizating time or thermal treated at 300℃, the BET value of the powders could reach 90-115 m~2/g. On the whole, there are rich and cheap original materials while choosing ovalbumin as template. Moreover, it provides a mild reactive condition and simple method and can help to obtain n-HA with high BET value.According to the results obtained from the orthogonal experiments, we synthesized the hydroxyapatite-pyrophosphate calcium (HA-CPP), hydroxyapatite/protein (HA/protein) composite with low phase transformation temperature, large hydroxyapatite particles, and the bobierrite and amorphous titanium phosphate using microbe as template. The micro-structure of the powders were characterized by Brunauer–Emmett–Teller (BET) surface areas, wide-angle and low-angle x-ray powder diffraction (XRD) patterns, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), atom force microscope(AFM), ultra-violate visible spectroscopy (UV-VIs) and the thermal gravity/differential scanning calorimetry (TG/DSC). The results showed that the HA-CPP polycrystals with ordered mesopores sized at 6.67 nm were synthesized, and the forming mechanism was further discussed by using the theory of lyotropic calcium liquid crystal (CLC). Moreover, HA/protein composites using ovalbumin as biotemplate could transform toβ-tricalcium phosphate (TCP) nanocrystals as low as about 550℃, and the biomineralizing mechanism of HA mediated by the ovalbumin was analyzed. The synthesis of large HA particles and the synthesis of the bobierrite and amorphous titanium phosphate showed that the macro-biomolecules had great effects on the nucleation, growth, crystallinity and morphology of the inorganic materials.The electrical conductivities, electric dielectric constants and the adsorption and the emission spectra of the powders synthesized through different methods were characterized. It showed from the zeta potential value that the positive surface charges had great relation to the preparation methods but the thermal treatment and the heat-preservation time. The n-HA had positive charges after a long biomineralization time because of the chemical bond between the surfactant and the particles and the substitution of CO2 to the PO43-. The conductivities of the powders were changed with the increase of the calcining temperature, indicating that the connection of the surfactant and the particles were changed. The electric dielectric constants of the samples without surfactant which had the biggest value of 330 were much larger than that with surfactant as shown in the control experiment. The microwave power had the similar effect on the electric dielectric constants of the powders with biosurfactant. The adsorption and the emission spectra of the powders were measured on the purpose of developing new properties for the powders prepared by the biomineralizing routes.The main innovations of this paper are the synthesis of multi-shaped nano-HA by using the green biomineralization method in the mild condition. Mesoporous HA-CPP polycrystal has wide prospect in the application of drug deliverys. The HA/protein composite with low phase transformation temperature is expected to be used to prepare the active bone cement. The studies on the photic and electric properties are to explore the new use of the materials, such as, the fluorescent marking and fluorescence imaging technology.
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