| Luminescent quantum dots-semiconductor nanocrystals are a promising technology in the applications of immunoassay as fluorescence probes.There have been numerous reports of conjugating antibody with various different organic fluorescent dyes,including Rare-earth Chelate, FITC,TRITC,and Tetraethyl-Rhodamine.As the result of CdTe nanocrystals have greater exciton Bohr diameter of 15 um,which have unique electronic and optical properties such as high quantum yield,a narrow emission bands continuous broad absorption band,and high resistance to photo-bleaching,receive more concerns in recent years.The experiment results demonstrate that the QDs-based fluorescence probes can exhibit good sensitivity and exceptional phot(?)-stabil(?)ty, which would provide a new probe in detecting Immunoassay Environmental Persistent Organic Pollutants.(â… ) The water-soluble CdTe nanocrystals have been synthesized by using mercapto-acetate acid as stabilizing agent in four refluxing hours.Single factor methods has been used in grouping for the best conditions of the experiment.The products were characterized by using TEM,XRD, UV-Vis and fluorescence spectra.Here,the optical molar ratio of Cd2+:HTe-:TGA is found to be 1.00:0.20:2.40.Maximum fluorescence produced at pH 11.0 and 96℃,with maximum emission wavelength at 696 nm.Under optical conditions,The quantum yield of the red CdTe nanocrystals was measured to be 0.4254 and the half-peak width was.about 17 nm.Recent advances have led to the development of multifunctional nanocrystals probes that are very bright and stable under the complex condition.At the same time,CdTe / CdS core-shell nanocrystals were synthesized in aqueous solution while using the thiourea as to the source of sulfur.As the result of the CdTe nanocrystals were perfectly synthesized,so it can be used to developping a new fluorescent nanocrystals probe for Environmental monitoring and chemical analysis.(â…¡)With the mercaptoethanol as stabilizing agents,the CdTe nanocrystals were prepared under wild condition.A new fluorescence method has been developed for the determination of copper(â…¡) based on the florescence intensity of CdTe nanocrystals in pH = 7.4 phoshate buffer solution.Under optimum condition,when the concentration was 1.25×10-4 mol/L, the relative fluorescence intensity of QDs is linearly proportional to the concentration of copper(â…¡) from 10μg/L to 320μg/L.The linear equation isâ–³I = 0.9093 + 0.0032C(μg/L ) and the limit of detection is 1.06μg/L.The method has been used to determine trace amounts of copper(â…¡) in vegetation with satisfactory results.(â…¢) Luminescent water-soluble CdTe nanocrystals capped with different thiol carboxylic acid were synthesized in aqueous medium and then cross linked to bovine serum albumin(BSA) with NHS.The QDs-BSA conjugates were confirmed,and their stability has been proved.Due to the electrostatic interaction between the CdTe nanocrystals and BSA,it has been investigated with ultraviolet visible absorption spectroscopy and florescence spectroscopy.In addition to the BSA can link carboxyl mercaptoacetic acid on the surface of the CdTe,there were seven adjacent disulfide and cadmium link more closely so that CdTe and BSA can form a stable CdTe / BSA Core-shell nanocrystals.It was also found that the absorption intensity of CdTe nanocrystals significantly decreased after adding BSA solution and just oppersite to the florescence intensity of CdTe nanocrystals,showing that CdTe nanocrystals were bond to BSA.So CdTe nanocrystals could be link the antibody as the fluorescence probe.(â…£) The CdTe nanocrystals has strong fluorescence emission at 696 nm after modified by mercaptoacetic acid.With the effect of EDC and NHS,the binding of the PCB4(PBB,PH,NA) antibody with CdTe nanocrystals was prepared,and this bind had fluorescence characteristics.The results of the F / P is between one and five.Therefore,The CdTe nanocrystals showed that it could be used for determination of PCB4(PBB,PH,NA) antibody as fluorescence immunoassay regent.
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