Construction Of Time-resolved Luminescence Sensing Platform Based On Two-dimensional Nanomaterials

Since the advent of graphene,two-dimensional nano-materials have attracted wide attention.A variety of two-dimensional nano-materials have been developed.These materials provide potential applications not only in the field of optics,electronics and mechanical,but also in the field of biochemical analysis.In recent years,a large area of blue-green algae outbreaks occurred in southern China,resulting in drinking water to be seriously polluted.Among microcystins,microcystin-LR(MC-LR)is the most widespread.To this regard,the World Health Organization(WHO)provides that the content of MC-LR in drinking water is allowed to be less than 1.0 ?g/L.Therefore,the development of a rapid and highly sensitive analytical method for MC-LR is of great significance.Based on this problem,the research in second chapter of this paper established a highly sensitive homogeneous time-resolved fluoroimmunoassay method for the quantitative detection of MC-LR in water samples,using a fluorescent rare earth complex BHHBCB-Eu3+ as a label and two-dimensional tungsten disulfide nanosheets as a fluorescence quencher.Compared with the traditional immunoassay methods for MC-LR,the whole process of assay was carried out in homogeneous solution without separation,washing steps and time-consuming immobilization of antigen or antibody,which allows the new method to be more convenient for the analysis of MC-LR in water samples.The proposed method has the advantages of wide linear range,good precision and accuracy,high selectivity,and comparable sensitivity with a detection limit of 0.3 ?g/L,which satisfied the World Health Organization(WHO)provisional guideline limit of 1.0 ?g/L for MC-LR in drinking water.In addition,the application of two-dimensional nanomaterials in biosensing was further explored in third chapter of this article.Using a fluorescent rare earth complex BHHBB-Eu3+ as the signal reporter molecule,MnO2 nanosheets as the quenching platform and the precursor of the magnetic resonance signal,a fluorescence/MRI dual-model probe method was developed for the quantitative detection of reduced glutathione(GSH).In the research,the water-soluble MnO2 nanosheets were firstly prepared.After they were mixed with BHHBB-Eu3+ solution,the fluorescence of Eu3+ complex was quenched.In the presence of GSH,MnO2 was reduced to Mn2+,which enabled not only the Eu3+ fluorescence to be restored,but also the Mn2+ magnetic resonance signal to be detectable.The whole process could be completed within 10 min.The results show that the method can be used for the fluorescence and magnetic resonance dual-model detection of GSH with a very fast response speed and a good linear relationship in a certain concentration range of GSH.The new method combines the advantages of high sensitivity and no background fluorescence interference of time-resolved fluorescence detection and high spatial resolution and penetrating depth of magnetic resonance imaging(MRI)detection,which provides a good platform for the fluorescence/MRI dual-model detection of GSH in living samples.