The Fabrication And Application Of Immunosensor In The Detection For Tuner Makers Basing On The Carbon Nano-Materials

Terminal cancer of the high mortality rate,but most of the tumors if was timely found that 70%to 80%or even 90%can be cured,therefore,early diagnosis and timely treatment of tumor is the key to improve the recovery rate of cancer patients.Carcinoembryonic antigen（CEA）and Prostate specific antigen（PSA）are mainly used as tumor makers for diagnosing a disease,which have an important relationship with Lung cancer,ovarian cancer,breast cancer and prostate cancer.Thus,it has important clinical value to test the content of CEA or PSA in human serum with a rapid and accurate method.Due to the advantages of low cost,simple preparation,short response time and yet accurate and sensitive platform,the method was widely used to test the content of the tumor markers.The pivotal steps for electrochemical immunosensor are the biological recognition system and the signal transduction between the biorecognition event and detected current signal.A series of immunosensors were fabricated with all kinds of carbon materials and noble metal nanoparticles,and the detailed researches were described as follows:1、Ultrasensitive non-enzymatic immunosensor for carcino-embryonic antigen based on palladium hybrid vanadium pentoxide/multiwalled carbon nanotubesA novel and sensitive sandwich-type non-enzymatic electrochemical immunosensor was fabricated for quantitative monitoring of carcino-embryonic antigen（CEA）.Nanocomposite of stannic oxide/reduced graphene oxide was used as substrate material to increase the specific surface area and enhance the conductivity of the glassy carbon electrode.Gold nanoparticles（Au NPs）were introduced to link substrate materials and primary antibodies（Ab₁）and accelerate the electron transfer in this system.At the same time,the palladium nanoparticles（Pd NPs）-vanadium pentoxide（V₂O₅）/multiwalled carbon nanotubes（MWCNTs）were used as the label of secondary antibodies（Ab₂）.This composite label has shown excellent catalytic activity towards the reduction of H₂O₂.The nanomaterial-based signal amplification can improve the sensitivity and lower the limit of detection.The proposed immunosensor showed wide linear range from 0.5 pg·mL^-1 to 25ng·mL^-1 with limit of detection of 0.17 pg·mL^-1.2、A novel sandwich-type immunosensor for detection of Carcino-embryonic antigen using silver hybrid multiwalled carbon nanotubes/manganese dioxide.A novel sandwich-type nonenzymatical electrochemical immunosensor was fabricated for quantitative determination of the carcino-embryonic antigen（CEA）.β-cyclodextrin/multiwalled carbon nanotubes（β-CD/MWCNTs）were chosen as substrate material to immobilize abundant first antibodies（Ab₁）and enhance the electrical conductivity.The synthetic silver nanoparticles-carbon nanotube/manganese dioxide（Ag NPs-MWCNTs/MnO₂）was used as electrochemical labels of secondary antibodies（Ab₂）towards enhancing the electrochemical signal.MnO₂ and Ag NPs which have high catalytic performance towards the reduction of H₂O₂ were used for fabrication of the immunosensor to achieve dual signal amplification.Under the optimal conditions,the electrochemical immunosensor exhibited a wide linear range of 0.0001⁰.5 ng·mL^-1 and0.5-10 ng·mL^-1 respectively with a low detection limit of 0.03 pg·mL^-1 for CEA.3、Label Electrochemical Immunosensor for Prostate-specific Antigen Based on Graphene and Silver Hybridized Mesoporous Silica.In this study,we fabricated an electrochemical immunosensor for PSA detection using the amino-functionalized graphene sheet-ferrocenecarboxaldehyde composite materials（NH₂-GS@FCA）and silver hybridized mesoporous silica nanoparticles（Ag@NH₂-MCM48）.Under optimum conditions,the fabricated immunosensor showed a wide linear range with PSA concentration(0.01 to 10.0 ng·mL^-1).Low detection limit(2pg·mL^-1)proved the high sensitivity,stability and repeatability.