The Fabrication And Application Of Immunosensor In The Detection Of Tuner Makers Based On The Functionalized Au Nanoparticals

With the development of electroanalytical chemistry,some new methods and techniques have emerged,such as electrochemical biosensors.An electrochemical biosensor is a device that converts biochemical reactions into electrical signals,which usually acting as a biomolecule recognition or biochemical receptor throw modifying biological components,such as antigen-antibody,to the surface of an electrode.The immunoassay is established using a highly selective reaction between an antibody and an antigen,which has a high selectivity and a low detection limit.An electrochemical immunosensor is an integrated element that performs specific quantitative or semi-quantitative analysis based on the antigen-antibody reaction,wherein the antigen and the antibody are molecular recognition units that are linked to an electrochemical transconductance unit.The concentrations of the measured material are corresponding to electrical signal,which can be applied to the detection of multiple antigens,haptens or antibodies.The rapid development of nanotechnology has greatly improved the sensitivity of disease detection,in which gold nanoparticles have been widely concerned due to its special physical and chemical properties.In this paper,a series of electrochemical immunosensors were constructed by using carbon nanocomposites,metal oxides,noble metal nanoparticles and gold nanoparticles.The main contents are as follows:1.An ultrasensitive sandwich-type electrochemical immunosensor based on Cr³⁺@Au@OMC for IgG detectionIn this study,a sensitive and novel sandwich-type electrochemical immunosensor was used to quantitatively detect IgG.A non-enzyme-based immunosensor based on carbon material and noble metal was prepared.The ability of the sensor to capture and load the antibody was controled by the ratio of Cr³⁺ and Au nanoparticles,which can improve the catalytic ability of immunosensor.The detection range is 10-100 ng/mL and the minimum detection limit is 3.33 fg/m L.The immunosensor exhibits a low detection limit,a wide detection range and good reproducibility,selectivity,and stability.2.A novel label-free electrochemical immunosensor based on functionalized nitrogen-doped graphene quantum dots for carcinoembryonic antigenThe novel PtPd/N-GQDs nanocomposites were synthesized by in-situ synthesis method.Then,the PtPd/N-GQDs nanocomposites were supported on the surface of gold nanoparticles by self-assembly of amino groups and gold nanoparticles.The obtained PtPd/N-GQDs@Au has good electrocatalytic performance,large specific surface area,good dispersion properties and electron transfer ability.These properties are beneficial to capture antibodies and improve the sensitivity of the constructed immunosensor to achieve quantitative detection of CEA.The detection range of the constructed immunosensor is from 5 fg/m L to 50 ng/m L and the detection limit is 2 fg/mL.3.An ultrasensitive sandwich-type electrochemical immunosensor based on the signal amplification strategy of echinoidea-shaped Au@Ag-Cu2 O nanoparticles for prostate specific antigen detectionIn this process gold nanoparticles functionalized nitrogen-doped graphene quantum dots（Au@N-GQDs）was synthesized through a simple and green hydrothermal procedure to enhance conductivity,specific electrode surface area and quantity of immobilized primary antibodies（Ab1）.Subsequently,the prepared echinoidea-shaped nanocomposites（Au@Ag-Cu2O）composed of Au@Ag core-shell nanoparticles and disordered cuprous oxide was prepared successfully to label the secondary antibodies（Ab₂）,which convened the advantages of good biocompatibility and high specific surface area.Because of the synergetic effect present in Au,Ag and Cu2 O,the novel nanocomposites exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide（H2O2）for the amplified detection of PSA.Therefore,the as-proposed immunosensor for the detection of PSA possessed wide dynamic range in the range from 0.01 pg/m L to 100 ng/m L with a low detection limit of 3 fg/m L.Furthermore,this sandwich-type immunosensor revealed high sensitivity,special selectivity and long-term stability,which had promising application in bioassay analysis.