| Biomedical materials,as an important foundation of biotechnology and biomedical engineering,is a cross-multidiscipline concerned to the most widely research fields involving materials,biology and medicine.The current development of biomedical materials is facing many challenges and opportunities,requiring to establish new research strategies which are able to break through the traditional empirical and semi-empirical research models,on the basis of molecular level of design and assembly,according to relationship between structure and performance of materials,and finally by means of in-situ and high-throughput evaluation technology.It is necessary and urgent to develop various,novel,efficient and precise methods for studying biomedical systems due to the basic characteristics and extreme complexity of interactions between cells and surfaces of biomaterials.High-throughput evaluation has recently become an attractive technology in biomedical assessments in the world,because of obvious advantages such as high efficiency,accuracy and low-cost.Based on the excellent photocatalytic property and controllable constructions of TiO2 nanotube,we have developed an approach to fabricate superhydrophobic-superhydrophilic micro-patterns on medical titanium by molecular self-assembly and photocatalytic lithography,which can be a template to further build all kinds of micro-patterned biological material with gradient chemical composition and morphology by controlled electrochemical deposition/etching and chemical approaches like surface assembly technology.It is helpful,which can enable high efficient study of interaction mechanism of cells and biomaterial surface and accurate evaluation of the relationship between structure and property of biomaterial interface.In this thesis,we concentrated(1)to develop a novel approach for fabricating several biocompatible coatings with gradient structure and property on the micro-patterned TiO2 nanotube on medical Ti substrate,(2)to explore high-throughput evaluations of structures and properties of biomaterials,and to further understand the relationship of structures-properties based on such gradient micro-patterned biomaterials.Various advanced physicochemical methods were employed to high-throughput characterize structure and chemical composition of the gradient biomaterials.The biological responses of the biocompatible coatings were high-throughput evaluated by in vitro biomineralization tests,in vitro cell culture and bactericidal test.The main progresses and achievements of this study are outlined as follows:(1)Based on the superhydrophobic-superhydrophilic micro-patterned template,a facile construction of gradient micro-patterned octacalcium phosphate(OCP)coatings on titanium has been successfully developed for high-throughput evaluation of biocompatibility.The gradient OCP coatings with tunable crystal morphologies involving scattered-flower-like,scattered-flower-ribbon-like,short-ribbon-like and long ribbon-like were constructed at the different micro-units on the same surface.The significant difference of mineralization behaviour of the gradient OCP coatings at the micro-patterns was observed visually and efficiently.The in vitro culture of MC3T3-E1 cell showed that the number and morphology of cells selectively adhered on the micro-units of gradient structure of OCP coatings were distinctly different,indicating that the cells are sensitive to the different structures of OCP coatings on medical titanium.It has been demonstrated that the gradient micro-patterned constructions can be a powerful method for high-throughput screening the biocompatibility of biomaterials.(2)The gradient micro-patterned OCP/Ala-Gln composit coatings has been constructed on titanium.Compared with OCP coatings,adding of Ala-Gln which makes crystal whisker of OCP deposition more orderly and slight can effectively improve activity of cells in contact with material and biocompatibility of biomaterial.Here the Ala-Gln was firstly used to modify the gradient micro-patterned OCP coatings of biomedical materials interface.It is found that the Ala-Gln can not only tune the crastal structure of OCP precipitation,but also improve the microenvironment at the cell/materials interface.(3)A tunable construction of micro-patterned TiO2/Ag coatings with Ag nanoparticles of gradient morphologies and diameters has been developed on the superhydrophobic-superhydrophilic micro-patterned template by consecutive pulling combined with pulsed electrodeposition,silver mirror reaction,ultraviolet light radiation and dopamine reduction.The as-prepared gradient micro-patterned TiO2/Ag coatings was used for high-throughput evaluation of bacteriostatic ring formation and bacterial adhesion.The significant difference of antibacterial property of the gradient TiO2/Ag coatings constructed by four ways was observed visually and efficiently,indicating the Ag nanoparticles prepared by ultraviolet light radiation was of the best antibacterial property,which is helpful to screen out the preparation and properties of biomaterials.(4)Construction of gradient micro-patterned TiO2/Ag Ala-Gln composite coatings has been developed imitating the preparation of the gradient micro-patterned TiO2/Ag coatings by consecutive pulling combined with pulsed electrodeposition,silver mirror reaction,ultraviolet light radiation and dopamine reduction.Compared with TiO2/Ag coatings,it indicated that the Ala-Gln can make Ag nanoparticles more tunable and well-spreaded on surface,and can effectively reduce the Ag cytotoxicity and improve the antibacterial property of biometerial at the same time.(5)A tunable gradient structure TiO2 nanotube array films(NTAs)on titanium with sponge-like NTAs and NTAs with gradient diameter of 30nm,60nm and 90nm has been constructed by pull-stop-pull electrochemically anodization.And the formation mechanism of TiO2 NTAs with different nanostructure formed on a single titanium surface was discussed in detail.It is found that the gradient structure of TiO2 NTAs behaved similarity in wettability translation and different properties in crystalline structure transition by evaluation on the gradient TiO2 NTAs as a high-throughput template.The in vitro culture of MC3T3-E1 cells showed that the number and morphology of cells adhered on the gradient TiO2 NTAs were distinctly different,indicating that the cells is highly sensitive to the structures of TiO2 nanotubes.The significant difference of the formation of biofilm of Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)onto the gradient TiO2 NTAs was also observed visually and efficiently.It has been demonstrated that the construction of the gradient TiO2 NTAs can be an efficient platform for high-throughput screening the relationship of structure-properties on surface,especially for bioproperties.(6)The micro-patterned OCP coatings was constructed on the substrate with gradient TiO2 NTAs as the superhydrophobic-superhydrophilic micro-patterned templates.The gradient structure of TiO2 NTAs surface was able to induce the difference in electro-depositing of OCP crystal,resulting in different OCP morphologies.Therefore,an alternative way for high-throughput constructing diversified morphologies of OCP coatings can be proposed.(7)The effects of the preparing conditions of pulsed electrodeposition,silver mirror reaction and ultraviolet light radiation and the nanostructure of TiO2 NTAs on the morphologies and diameters of Ag nanoparticles were systematically evaluated by the gradient TiO2 NTAs as a high-throughput template.It is found that preparation conditions play a crucial role in the formation of Ag nanoparticles.Meanwhile,Ag nanoparticles with different diameters and quantities were formed respectively on the sponge-like TiO2 NTAs and TiO2 NTAs with gradient diameter of 30nm,60nm and 90nm at completely the same preparation condition. |
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