Mn-doped Phosphorescent Quantum Dot And Its Imprinted Materials For Microcystins Detection

Microcystins analysis has attracted wide attention in various countries owing to its high toxicity and stable chemical properties.And it is also a strong liver tumor promoter.Doped phosphorescent quantum dots have unique properties.The QDs targeting at room temperature phosphorescence(RTP)signals have been used in environmental detection,biosensor,food detection,photoelectric equipments and so on.QDs can be functionlized by modifying the surface environment.The functionlized QDs can be used for specific analytes by exploiting different modifiers.Through binding Molecular imprinting and RTP-based doped QDs,characteristic recognition sites can be synthesized.The detection process can also be conducted in phosphorescence mode,which has attracted increasing interest.Based on the research of Mn-doped phosphorescent quantum dots,the synthesis of different Mn-doped phosphorescent materials was discussed in this paper.And we studied the detection of microcystins by the combination of RTP quantum dots and fragment molecular imprinting techniques.We have assembled Zn Se:Mn/Zn S QDs-monoclonal anti-microcystin-LR(anti-MC-LR)antibody bioconjugates as a RTP probe using EDC/NHS chemistry for detecting MC-LR.Once the specific interactions occurred between these Microcystins(MCs)and their antibodies on the surface of Zn Se:Mn/Zn S Q Ds,the RTP of Zn Se:Mn/Zn S QDs was quenched with the increased concentration of MC-LR.Under the optimized conditions,the linear range of MC-LR was determined to be 0.9-8.8 n M.The linear relationship between(P₀-P)/P₀ and concentration of MC-LR was observed with the regression equation(P₀-P)/P₀=0.03908C+0.0456 with the detection limit of 0.038 n M.The results are in good agreement with those obtained using the chromatographic method.This method was also applied to the determination of MC-LR in water samples in the environment,indicating the practicability of the developed RTP immunoassay.By combining RTP Mn-Zn S QDs and double dummy fragment imprinting,a new RTP probe was constructed based on quenching L-Cys-Mn:Zn S imbedded fragment imprinting silica(LIFIS).A fragment or a structurally similar portion of the target analyte microcystins are used as dummy templates,Mn:Zn S Q Ds coated with L-cysteine are embedded in the Si O₂ by hydrolysis of tetraethoxysilane and can serve as the phosphorescence signal for detection.L-arginine and amylbenzene were used as double dummy fragment molecular templates to form recognition sites to detect a series of MCs.This new method require no derivatization and inducer.Under optimized conditions,the linear range of MC-LR was determined to be 0.0025-0.165 n M and the regression equation was?P/P₀=0.0150+24.70C_MC-LR(R²=0.9886).The imprinting factors of the double dummy fragment phosphorescent QDs imprinted material and the two single dummy fragment imprinted materials were 11.2,2.2,and 1.3,respectively.At the same time,the real samples analysis of MC-LR in the Yangtze River and lake water proved the practicability of the method.