Research On A New Type Of Electrochemiluminescence Sensor Based On Rare Earth Nanomaterials

Rare-earth(RE)-based nanoparticals are important among luminescent materials due to its high luminescent quantum yields,narrow emission peaks,wide emission spectrum bands,long fluorescence lifetime and low toxicity.Up to now,upconversion nanoparticles(UCNPs)is proposed as a new promising class of biological luminescent labels.Recently,RE-based luminescent nanoparticals as a new electrogenerated chemiluminescence(eletrochemiluminescence,ECL)material is attracting broad attention in the world.The ECL performance of RE nanoparticals has low toxicity,considerable ECL intensity and more stable cathodic signals.Accordingly,in this paper,three types of functional nanoparticals were prepared and applied to construct label-Free immune biosensors on the surface of glassy carbon electrode(GCE).This work not only broadens the range of application of RE-based luminescent materials,but also plays a great role in the clinical diagnosis and treatment of diseases.In this paper,three types of RE nanoparticals were synthesized and modified to obtain functional nanoparticals,then they were used to construct biosensor on the surface of GCE.The details outline as follows:1.We present a thermal decomposition method to synthesize hydrophobic core-shell BaGdF5:Yb,Er@BaGdF5:Yb(BGF@BGFY)NPs modified via folic acid(FA)to form hydrophilic BGF@BGFY NPs(FA-BGF@BGFY NPs).Moreover,the ECL immunosensor was constructed by a layer-by-layer modification of FA-BGF@BGFY NPs,EDC/NHS,BSA.We have designed a molecular recognition mediated ECL strategy for label-free and sensitive detection of folate receptor(FR)cells(HeLa cell as a model)on FA functionalized,according to the specific recognition between FA and over-expressed FR anchored to the cell membrane.Importantly,the cell biosensor exhibited good stability and acceptable fabrication reproducibility and accuracy,showing great promising for clinical application.2.EuS nanoparticles doped with manganese ion(Mn2+),Eu0.9Mn0.1S nanoparticles,resulting in an enhancement of their ECL property was prepared by thermal decomposition method.Additionally,by exchanging the ligand on the surface of NPs,the as-prepared NPs was rendered water-soluble and then employed as ECL immunosensor for carcinoembryonic antigen(CEA)detection.The ECL intensity of Eu0.9Mn0.1S NPs was about 4-fold as strong as that of pure EuS NPs and its signal response was stable.The proposed immunosensor exhibited acceptable stability and reproducibility,and the assay results of serum samples were in acceptable agreement with the reference values.3.In this work,we prepared copper ion(Cu2+)doped europium sulfides,Eu1-xCuxS NPs by thermal decomposition.All materials were characterized by transmission electronic microscope(TEM),X-ray powder diffraction(XRD),inductively coupled plasma atomic emission spectroanalysis(ICP-AES),ultraviolet visible light absorption spectroscopy(UV-vis)and fluorescence emission spectra(PL).We have compared the influence of different doping amount of the Cu2+on the PL and the ECL property of EuS NPs.Interestingly,both PL and ECL intensity of Eu1-xCuxS NPs were the strongest when x=0.05.We obtained FA-Eu0.95Cu0.05S NPs after surface modification and designed a molecular recognition-mediated ECL strategy for label-free and sensitive detection of FR(+)cell(HeLa cell as a model)on FA functionalized Eu0.95Mn0.05S NPs-modified GCE.The as-prepared cell sensor showed a high sensitivity and good stability,a widely detection range from 3.25×102 to 5.2×105 cells/mL with a detection limit as low as 246 cells/mL for the detection of cancer cells,showing great promising for clinical application.