Research On A New Type Of Biosensor Based On Nanocomposite Signal Enhancement

Introducing nanocomposites to the sensitive interface of biosensors,the immobilization amount of biological molecules increases and detection signal is greatly improved,which can improve the sensitivity and selectivity of biosensor.Nanocomposites-based biosensors for ultrasensitive detection of biological molecules become a promising research field.In this paper a variety of functional nanocomposites were prepared and applied to sensitive interface of biosensors.Details are as follows:1.The Au-F127 strawberry-like nanocomposites were prepared by one-step method and characterized by transmission electron microscopy(TEM),ultra-violet visible(UV-vis)spectra and attenuated total reflection-Fourier transform infrared(ATR-FTIR)spectra,etc.Au-F 127 nanocomposites offered a large surface and multifunctional substrate for the effective immobilization of AuNPs to make electrochemical signal amplied.A simple label-free electrochemical immunosensor for sensitive detection of carcinoembryonic antigen(CEA)was developed by immobilizing anti-CEA antibodies onto the Au-F 127 nanocomposites modified glassy carbon electrode(GCE).The immunosensor showed high sensitivity,good selectivity and fast response.2.The reduced graphene oxide-upconversion nanoparticle composites(rGO-BaYFS:20%Yb,2%Er)with a high and stable ECL signal were synthesized by hydrothermal method and their properties and morphology were characterized by TEM,X-ray diffractometer and fluorescence spectrophotometer,etc.The oil-soluble rGO-BaYF5:20%Yb,2%Er nanocomposites were to be water-soluble by means of ligand exchange and then modified on the surface of GCE.Then,Poly(diallyldimethylammonium chloride)(PDDA)and AuNPs were assemblied layer-by-layer on the surface of modified eledtrode to construct ECL immunosensor for detecting CEA sensitively.3.The water-soluble NaYF4:20%Yb,2%Er nanoparticles were prepared by hydrothermal method.AuNPs on the surface of upconversion nanocomposites can not only enhance ECL intensity of nanomaterials,but also make them surface functionalized to make easier to bind amino,mercapto groups and so on.The Au-NaYF4:20%Yb,2%Er nanocomposites as ECL emitters were used to fabricate a novel biosensor for sensitive detection of Hela cells using folic acid to capture FR overexpressed Hela cells.