Study On The Electrochemical Immunosensors Based On Noblemetal Nanocomposites

It is well known cancer presents a serious problem to threat human health.Early detection anddiagnosis are the key factors toimprove the cure rate of cancer and the quality of postoperative life.Therefore,the establishment of sensitive detection methods has important academic significance and application value for the diagnosis and treatment of cancer.In this paper,we prepared a series of nanocomposite sensing materials based on the excellent performance of noble metal nanocomposites and advantages of electrochemical immunoassay.The as-proposed immunosensor exhibited high sensitivity for the detection of various tumor markers.?1?The silver nanoflower-molybdenum disulfide/multiwalled carbon nanotubes?SNFs-NH2-MoS2/MWCNTs?were used as a label to design electrochemical immunosensor.MWCNTs inserted between the MoS₂ layers can restrain agglomeration of MoS₂ and improve the conductivity.SNFs-NH₂-MoS₂/MWCNTs provided an excellent sensing interface and improved the sensitivity of the electrochemical immunosensor.The proposed electrochemical immunosensor showed a limit detection of 0.03 pg/mL for squamous cell carcinoma antigen?SCCA?.?2?Based on good catalytic performance of gold and silver core-shell structure nanoparticles?Au@AgNPs?,Au@AgNPs loaded on the amino functionalized magnetic graphene with high specific surface area can conjugate with more antibodies.To further improve the sensitivity of the electrochemical immunosensor,the Ni²⁺was adsorbed on the surface of composite and the as-synthesized GS-Fe₃O₄/Au@Ag/Ni²⁺was used as a novel label.The proposed immunosensor displayed enhanced sensitivity for detection of carcino-embryonic antigen with a limit detection of 0.0697 pg/mL compared to similar methods.?3?In order to improve the sensitivity of the electrochemical immunosensor,using gold platinum?Au@Pt?,transition metal oxide Co₃O₄ and the semiconductor oxide CeO₂,we synthesized Co₃O₄@CeO₂-Au@Pt nanocomposite.Due to the synergetic effect of Co₃O₄,CeO₂,Au NPs and PtNPs,the Co₃O₄@CeO₂-Au@Pt possessed excellent conductivity,superb catalytic performance and good biocompatible and was used as labels.The fabricated immunosensor achieved sensitive detection of SCCA with a low detection limit of 33 fg/mL.?4?Novel nanocomposite TH/Ag@KIT-6/CMC/ILs by combining with silver nanoparticle?AgNPs?,thionine?TH?,ionic liquids?ILs?,CMC and KIT-6 have been prepared.TH/Ag@KIT-6/CMC/ILs showed good electrocatalytic performance and adsorption performance owing to the good electron transfer capability of TH,excellent conductivity of ILs and unique pore structure of KIT-6.In addition,CMC can effectively improve the dispersion of composite materials.Based on synergetic effect existing in TH/Ag@KIT-6/CMC/ILs,the sensitivity of the designed immunosensor has been further improved,and the low detection limit for SCCA is 17 fg/mL.In this paper,the designed four kinds of electrochemical immunosensors might provide new methods and ideas for sensitive determination of tumor marker and further expand the application range of different types of nanocomposite materials.It has laid good foundation for the further development of biomedical application of this kind of materials and devices.