Research And Application Of Electrochemiluminescence Properties Of New Rare Earth Materials NaYF 4 :Yb,Er

Rare earth doped upconversion nanoparticles(UCNPs)possess many advantages,such as narrow emission peak,long fluorescence lifetime,high photochemical stability,large stokes shift and low toxicity.As a new ECL-emitter,UCNPs have attracted wide interest.Recent decades have witnessed an explosion in research devoted to the electrogenerated chemiluminescence(electrochemiluminescence,ECL),which intrinsically represents a marriage between electrochemistry and spectroscopy.By integrating both advantages,ECL possesses unique superiorities over other optical methods.It does not require a light source,which not only simplifies the detection apparatus but also invalidates background signals from scattered light and luminescent impurities,thus leading to high sensitivity.The ECL technique has also become a powerful analytical tool in the detection of biomolecules,clinical diagnostics,environmental and food monitoring,biowarfare agent detection,etc.ECL-emitters,up to this day,have been through many vicissitudes and evolution.The advances concerning nanoparticles(NPs)-based ECL not only open a promising field for the development of new-generation ECL-emitting species,but also complement the conventional optical utilizations of quantum dots(QDs).Although compare with QDs,Rare earth doped luminescent nanoparticles based ECL have been proposed as a promising new class of ECL-emitter because of their attractive chemical and optical features,including low toxicity,considerable ECL intensity and more stable cathodic signals.The rare earth doped luminescent nanoparticles biofunctional nanoparticles can be used to realize enrichment of trace sample during bio-analytical detection and achieve the targeted labeling of living organisms simultaneously.It not only improves the detection sensitivity,but also expands applications of the materials.As is well known,carcinoembryonic antigen(CEA),an acidic glycoprotein with a molecular weight of about 200 kDa,is recognized as the mainly used tumor marker in clinical cancer screening and early diagnostic applications.Therefore,sensitive,precise,and accurate assays for the determination of CEA with low concentration level in complex biological samples are necessary.Immunoassays are based on the use of an antibody that reacts specifically with an antigen to be tested,which is a powerful analytical tool for CEA determination.Then use are earth doped luminescent nanoparticles for labeling of immunoassays and detection of CEA.The main contents are outlined as below:1.A simple method was used for the preparation of NaYF4:Yb,Er up-conversion nanoparticles,then they were changed into water soluble by oxidizing oleic acid.A simple and sensitive electrochemiluminescence immunosensor with K2S2O8 as a coreactant for detection of carcinoma embryonic antigen(CEA)was constructed by using NaYF4:Yb,Er up-conversion nanoparticles as bionanolabels.The electrochemiluminescence immunosensor provided a good linear range from 0.01 to 40 ng mL-1 with a low detection limit of 3.1 pg mL-1.The ECL immunosensor showed a good reproducibility,stability and high sensitivity and could be used to detect CEA in practical samples.2.We report the ECL behaviors of the Mn2+ doped NaYF4:Yb,Er NPs for the first time.Mn2-doped NaYF4:Yb,Er NPs were synthesized via a facile strategy,and 4-fold ECL intensity enhancement of NaYF4:Yb,Er UCNPs has been achieved by Mn2+ doping.The characteristic of Mn2+ doped NaYF4:Yb.Er nanocomposites were performed by using transmission electron microscopy(TEM),energy dispersive X-ray spectrometer(EDS)and Fluorescence spectra.All the results indicate that NaYF4:Yb,Er upconversion nanoparticles were doped with Mn2+ successfully and the electrochemiluminescence platform was built.the as-prepared UCNPs were rendered water-soluble and then employed as ECL-emitter for CEA determination.The results indicated that the modified electrode can be used to determine CEA without interference from non-specific proteins with the low detection limit of 5.2 pg·mL-1.The biosensor can also be used for quantification of the concentration of CEA in real samples.3.NaYF4:Yb,Er NPs and carbon nanotubes composites were synthesized via a hydrothermal synthesis strategy for the first time.TEM,SEM-EDS and XPS analysis methods observe their morphology and particle size,ECL figure gets the results of its ECL signals.Through analysis of its composition,structure and properties,we obtain the following conclusions:(1)Carbon nanotubes are successfully compounded into NaYF4:Yb,Er nanoparticles.(2)CNT-UCNPs of ECL signals have been greatly improved,and have good ECL stability.