The Synthesis Of Bionic Nano TiO₂ And The Research Of Interface Characteristics Between Bionic Nano TiO₂ Andlipase

Dopamine is a kind of material with bionic adhesion properties,the research showed that it not only has excellentability to cover all kinds of materials, but also canprovide sites for the combination of many organic molecules.Therefore,The use of dopamine on the preparation of Bionic nano material with adhesive performance to the immobilized enzyme has a good research prospects.Firstly,the nano TiO₂ was preparation by hydrolysis, controlling the added amount of water to adjustthe particle size and specific surface area of nano titanium dioxide. AndSEM, EDS, XRD, FT-IR, thermal analysis, specific surface area analysis were used to characterize the prepared nano oxide titanium and commercial production of TiO₂ （P25） respectively,and compared the difference of their property.The results showed that the synthesized TiO₂ nanoparticles is a spherical shape with a regular morphology, uniform particles and better dispersion, the size reaches200nm when the water adding amount was 1.59mL, and the specific surface area reaches the maximum value for 133.684m/g; XRD showed that the crystal is anatase; energy spectrum analysis and thermal analysis showed that the nano TiO₂ microspheres has morewaterexists in the structurethan P25.By controlling the amount of water added to control the nano TiO₂ particle size, and achieve high specific surface area of nano titanium dioxide, in order to lay the experimental foundation for the later use of titanium dioxide as carrier for immobilized lipase.The bionic nano TiO₂ was synthesised by using dopamine to modify the TiO₂ nanoparticles which was synthesised on the former chapter.And study the effect of pH value, dopamine concentration, reaction time, stirring speed, reaction temperature on the synthesis of composite materials by using the lipase immobilization rate as indexes.The results show thatthe optimal conditions were as follows:pH,8.79; dopamine concentration,1.98mg/mL; reaction time,7.42h. On this conditions, the lipaseis immobilization rate of the bionic nano TiO₂ reaches 274.26mg/g, SEM analysis showed that dopamine modified on the surface of nano-TiO₂, formed a modified layer of 15-20nm;XRD characterization showed that dopamine modification of nano TiO₂ Crystal type had little effect;FT-IR characterization showed the peaks of dopamine at 1277cm-1 and 1483cm-1,thermal analysis showed that dopamine begin to decomposeat about 300℃. By the use of dopamine,the nano TiO₂ can effectively improve the lipase immobilization rate.The bionic nano TiO₂ was synthesised by using dopamine to modify the P25 which is a commercialized production. And then the bionic nano TiO₂ was used to immobilized lipase.The SEM,FT-IR,XRD were used to study the interface characteristics of bionic nano titanium dioxide adsorption lipase.The SEM and XRD characterization showed that the size of the TiO₂ particles increased about 20nm after the adsorption of enzyme, and the crystalline structure of the nano material was not affected by the adsorption; the IR spectra of samples show bands at 1647cm-1 and 1629cm-1 can be assigned to the C=N and the aromatic C=C stretching vibration, respectively, the thermal decomposition of dopamine and lipase in the temperature range of 200～500 was also analyzed. The immobilization of lipase was ascribed to the covalent binding of enzymes with the quinone groups.By optimizing the synthesis processes of adhesion biomimetic nano titanium dioxide,the solid loading rate of lipase was effectively improved, and the interfacial adsorption characteristics and adsorption mechanism of biomimetic adhesive nano titanium dioxide were studied. So that,a novel, simple, and universal application of biological enzyme immobilization technology was established.