Preparation of Biologically Active Materials by Biomimetic Process

In order to form the apatite nuclei on a surface of the substrate, the substrate was placed on or in CaO, SiO2-based glass particles which were soaked in a simulated body fluid with ion concentrations nearly e-qual to those of human blood plasma, and to make the apatite nuclei grow on the substrate in situ, the substrate, was soaked in another solution highly supersaturated with respect to the apatite. The induction period for the apatite nucleation varied from 0 to 4 days depending on the kind of the substrate. The thickness of the apatite layer increases linearly with increasing soaking time in the second solution. The rate of growth of the apatite layer increases with increasing degree of the supersaturation and temperature of the second solution, reaching 7um/d in a solution with ion concentrations which is as 1.5 times as those of the simulated body fluid at 60℃. The adhesive strength of the apatite layer to the substrate varies depending on the kind and roughness of the substrate. Polyethyleneterephthalate and polyethersulfone plates abraded with No. 400 diamond paste show adhesive strengths of as high as 4 MPa. This type of composite of the bone-like apatite with metals, ceramics and organic polymers might be useful not only as highly biaactive hard tissue-repairing materials with analogous mechanical properties to those of the hard tissues , but also as highly biocompatible soft tissue-repairing materials with ductility.

Calcium Phosphate Coating on Al_2O_3 Ceramics by a Biomimetic Method Using Electric Pulse Technique

The preparation of calcium phosphate （CP） coating on alumina ceramics using electric pulse stimulating methoe has been investigated. The cup-shaped alumina ceramics were soaked in a simulated body fluid （SBF）, and a square pulse potential with frequency of 1 Hz and voltage of 110 V was applied between the inner and outer surfaces of the alumina cup. Surface morphology of CP coatings during different deposition periods was observed by a Philips XL-30 scanning electron microscope （SEM）. Compositional analysis was examined by EDAX. The mechanism of nucleation and growth of CP coating was discussed. SEM result indicates that the coating comprises of a large number of tiny needle-like grains and has a porous microstructure. There is a strong bond between the deposited layer and Al2O3 substrate, which may be due to the gentle growth of the biomimetic method. The EDAX analysis indicates that main composition of the coating is calcium and phosphor. The formation of CP coating may be contributed to the stimulation of electric pulse and the high ions concentration which is 1.5 times of the concentration of SBF solution （1.5SBF solution）. Such surface functionalization method by electric pulse potential can be used to prepare CP coating on various electric-insulating bioinert materials for improving their bioactive character.

Biomimetic synthesis of all-inclusive organic-inorganic nanospheres for enhanced electrochemical immunoassay

A friendly biomimetic process was adopted for the mild preparation of"all-inclusive"organic-inorganic nanospheres,which effectively integrate biorecognition function and signal amplification function.The resulted Ca3(PO4)2-Ab2-BSA nanospheres were employed as signal labels for enhancing detection of nuclear matrix protein 22(NMP 22).The fabricated electrochemical immunosensor exhibited a linear range(0.08-77.00 U/mL)and an ultralow limit of detection(0.01 U/mL)towards NMP 22,which can be taken as a promising tool for clinical diagnosis of bladder cancer.