Electrochemical Immunosensor Based On Functional Nanocomposite For Detection Of Tumor Markers

Metal nanometer materials(gold nanoparticles,silver nanoparticles,platinum nanoparticles)and carbon nanomaterials(graphene oxide,carbon nanotubes),due to their excellent physical and chemical performance,i.e.super conductivity,good biocompatibility and huge surface area and so on,are widely applied in the construction of immunosensor.After functional nanocomposite material are formed by them,their various performance will be greatly enhanced.In this paper,functional composites modified electrodes are used to establish a new method for detection of tumor markers,here are five chapters in this thesis,and main contents are listed as follows:Charpter 1: introduction.A brief overview of cancer occurrence principle and its detection methods,the classification immunosensor and detection principle.The application of metal nanometer materials and carbon nanomaterials in immunosensors were reviewed in detail.In addition,we also introduced the research content of this paper.Charpter 2: A simple,sensitive and untagged impedance type immunosensor is formed by platinum nanoparticles/single-walled carbon nanotubes/chitosan composites(PtNPs-SWCNTs-CS)modified glassy carbon electrode,the platinum nanoparticles and single-walled carbon nanotubes functionlized with carboxylic group are used to capture anti-CEA.Under optimal conditions,experiment choose carcinoembryonic antigen(CEA)as the analysis model,impedance value increase follow the concentration of CEA from 0.01 to 12 ng/mL,they show a good linear relationship with a relative-low detection limit of 0.0042 ng/mL.The immunesensor has good stability and selectivity,the recovery rate is 94% to 108.6%.Charpter 3: a sandwich-signal suppression electrochemical method was developed for determination of prostate specific antigen(PSA).The excellent performance of dodecahedron Au-Ag Core-Shell nanocrystals(Au12@Ag)are synthesized as signal labels,under the presence of PSA,a sandwich electrochemical immunocomplex are formed on the surface of anti-PSA/AuNPs/GO/CS cryogel/AgNFs modified Au electrode.Silver nanoflower(AgNFs)as REDOX electronic media,and with the increase of concentration of PSA,the more the more immune complex formed on immunesensor,which inhibit the electrochemical response of silver and lead to DPV peak current signal decreases.Under optimal conditions,the formed immunosensor has a linearity range from 1.0 × 10-5 ng/m L to 20.0 ng/m L for the detection of PSA,and the detection limit is 3.6 × 10-6 ng/m L(S/N = 3)Charpter 4: Synthesised functional gold nanorods as molecular tags are used to label alpha-fetoprotein antibody(anti-AFP)to form anti-AFP-FGNRs immune conjugates,then droped on silver nano flowers(AgNFs)modified gold electrode surface to construct a sensitive electrochemical immunosensor for the determination of alpha-fetoprotein(AFP).The increase in the current was proportional to the concentration of AFP from 0.001 ng/m L to 20 ng/m L with a low detection limit of 0.5 pg/mL AFP at S/N = 3.The analysis results of clinical samples in accordance with commercial electrochemical luminescence method.Charpter 5: A novel sandwich type immune analysis method for sensitive detection of AFP in human serum was developed using popcorn shape of gold nanoparticles combined with anti-AFP and HRP(anti-AFP/popcorn-shaped GNP/HRP)as a biomarker for signal amplification.At the same time,the prepared graphene oxide-methylene blue-gold nanoparticles(GO-MB-AuNPs)nanocomposites dropped onto the surface of glassy carbon electrode(GCE)for capturing AFP antibody(anti-AFP)to build the immune sensing platform(anti-AFP/GO-MB-AuNPs/GCE).Under the optimized experimental conditions,the immunosensor has a detection limit of 0.32 pg/mL(S/N = 3)and can be used in the detection of real samples.