Study On Preparation Mechanism And Performance Of SiC Quantum Dots Fabricated Controllably By Chemical Corrosion

Long-term-distant tagging of living cells and their elaborate intercellular structure can provide important technical support for the biological theory analysis.Such method might find wide applications in monitoring cell growth mechanisms,tracking of transgenic processes,and efficient treatment of animal diseases.However,conventional fluorescent materials(e.g.fluorescent proteins,organic fluorescent dyes,CdX quantum dots(QDs)etc.)can not match all the qualities and conditions desired for fluorescence labeling living cells and its dynamic.Presently,as being a new material with excellent optical properties and biological compatibility that can provide both fluorescent labeling and imaging material at the same time,silicon carbide quantum dots(SiC-QDs)have been intensively studied in the material and biological societies.But so far,process and performance optimization of controllable preparation of SiC-QDs by chemical corrosion,preparation mechanism,living cell labeling mechanism and other issues have been systematically studied.In this paper,we did some efforts on the issues and conclusions were drawn as following:(1)The homogeneous silicon carbide nanoparticles as raw material,microstructure evolvement in the process of SiC-QDs preparing and the effect of fabrication parameters on the optical properties of SiC-QDs were investigated by multiple chemical etching,mechanical milling with ultrasonic cavitation and tomographic clipping in ultra-gravity field.Preparation mechanism and correlative relationships among the fabrication procedure,the microstructure and the fluorescent characteristics of SiC-QDs were revealed.Optimized process fabricated for SiC-QDs marking material was developed as the following steps: nanometer homogenous SiC via combustion synthesis?preparation of corrosion liquid?SiC particles etched in corrosion liquid ? decreasing acidity ? drying ? mechanical triturating treatment ? SiC particles secondly etched in corrosion liquid?decreasing acidity?drying?mechanical triturating treatment ? ultrasonic cavitation ? centrifugation chromatography in an ultra-gravity field?obtain the SiC-QDs in aqueous solution.(2)Fluorescence characteristics of SiC-QDs prepared by optimized chemical corrosion method and labeling mechanism for the living cells of pathogenic fusarium were explored.The results indicated that SiC-QDs photoluminescence intensity reached the maximum value when excitation wavelength of 340 nm.Red shift phenomenon of emission wavelength will occur with the increasing excitation wavelength.Because of larger Stokes shift and tunable color fluorescent,near ultraviolet detection for living cells with SiC-QDs fluorescent marking was achieved,which can be used as effective detection and quantitative analysis the autofluorescence cells.The results of labeling mechanism for living cells of pathogenic fusarium with SiC-QDs exhibited that quantum dots can reach the interior of the cells and homogeneous distributed in the cells through the clathrin endocytsis action,which achieved the stable fluorescent labeling.Moreover,model for living cells with SiC-QDs was established based on the experimental results and theoretical analysis.(3)The influence of physical growth for pathogenic fusarium with marking quantum dots was researched.The results showed that the growth speed,spore production and capacity of pigment production exhibited no inhibition phenomena with the control group.The results further indicated the excellent biological compatibility and stable fluorescent properties of SiC-QDs possess.Finally,the pathogenic mechanism of Fusarium oxysporum was studied by means of SiC-QDs labeling.And pathogenic mechanism of Fusarium wilt by pathogenic Fusarium oxysporum was proposed.