Electrochemical Immunosensor Based On Platinum Nanocomposites And Its Performance Research

Cancer is still the main cause of the human death.The studies found that early diagnosis and treatment is an effective way to reduce the mortality of malignant tumors,and tumor markers for the early diagnosis of the disease provides an important clinical value.This thesis focuses on constructing a series of sensitive electrochemical immunosensors for tumor markers detection through screening some unique properties of nanocomposite materials for signal amplification.The paper try to exploit new approaches that can improve sensitivity of single tumor markers of the immunosensor,develop multiple tumor markers detection.The research is as follows:An electrochemical immunosensor based on triple signal amplification strategy was constructed and used for the detection of alpha-fetoprotein.The process of electrochemical immunosensor was as follows: First,the ferrocene dicarboxylic acid was irradiated with light to synthesize the infinite coordination polymer nanospheres with electroactive activity.Then Pt NP_S(platinum nanoparticles)and heme/G-quadruple(a DNAzyme)was used to modify the polymer nanospheres.The electrochemical signal was further enhanced by the high efficiency catalysis of H2O2.Finally,the composite was constructed as a signal marker modified secondary antibody to construct a sandwich electrochemical immunosensor.The results show that the peak currents of the electrochemical immunosensor were proportional to the logarithm of AFP concentration over 0.1 pg/mL to 100 ng/mL,and the detection limit is 0.086 pg/mL.The preparation method of the electrochemical sensor is simple and sensitive,and it has good selectivity to AFP.The experimental signal amplification mode can be effectively used for protein detection,which improve the sensitivity of electrochemical immunosensor,and it is expected to provide a good platform for real sample testing.On the basis of the above research,an electrochemical immunosensor for simultaneous detection ofalpha-fetoprotein(AFP)and Carcinoembryonic antigen(CEA)was further constructed.The 1,1'-ferrocene dicarboxylic acid/gold-platinum nanocomposites(Fc/Au@Pt)and thionine/gold-platinum nanocomposites(Thi/Au @Pt)were prepared by Au-Pt shell-like nanoparticles.Then synthesized nanotags labeled anti-AFP and anti-CEA to construct sandwich-type immune sensors.The single was monitored through the labelling Au@Pt toward catalytic reduction of H2O2 at various peak potencials in the presence of thionine and ferrocene.Under the optimal conditions,the detection limits of AFP and CEA were 2.6 pg/mL and 3.2 pg/mL,respectively.In addition,the electrochemical immunosensor also exhibits good selectivity,stability and reproducibility.