| Tumor biomarkers,as biomolecules for cancer screening,can be accurately detected by studying sensitive detection methods,which can provide guidance for cancer diagnosis,treatment,and prognosis judgment,and have important application value and significance.Electrochemical immunosensors combine the advantages of specific immunity and electrochemical analysis technology,possessing high sensitivity and strong specificity,and have been widespread studied in the detection of tumor markers.In this paper,systematic research work has been carried out on the preparation,characterization,modification,performance testing,and application in electrochemical immunosensors of porous carbon based materials derived from MOFs.The main achievements are as follows:（1）A sandwich electrochemical immunosensor for prostate specific antigen（PSA）detection was constructed using trimetallic mesoporous nanospheres（Pd Ag Cu MNSs）as signal label and gold nanoparticles modified nitrogen doped porous carbon（Au/NPC）as the substrate.Using amphiphilic dioctadecyl dimethyl ammonium chloride as surfactant and micelle,Pd Ag Cu MNSs with uniform size,cylindrical open mesoporous channel and continuous crystal frame structure were synthesized through electrostatic adsorption and ascorbic acid co-reduction self-assembly.Its unique structure maximizes the use of multi-atoms to expose the catalytic sites,showing good biocompatibility and catalytic ability.NPC was prepared by a simple one-step pyrolysis strategy of biomimetic phyllite imidazole framework nanosheets,and the graphitization of microcrystalline structure enhanced the conductivity.In addition,gold nanoparticles are used to modify NPC,optimize electron transport and immobilize and capture antibody（Ab1）,further improving the stability and sensitivity of the immunosensor.Under the optimal conditions,the immunosensor showed excellent sensitivity,wide dynamic detection range and low detection limit of 3.29 fg mL-1,and good selectivity,reproducibility and stability.（2）With the trimetallic platinum palladium copper mulberry-like nanospheres functionalized boron and nitrogen double-doped carbon nanosheets（Pt Pd Cu/BNC）as the signal labels,gold nanoparticles modified sulfur and nitrogen doped hollow carbon（Au@SNHC）as the substrate,a sandwich electrochemical immunosensor was constructed for detecting cardiac troponin I（c Tn I）.Pt Pd Cu MBNSs were prepared by the"green"seed strategy,avoiding the use of surfactants,organic solvents and polymers that are difficult to remove.Its unique mulberry structure improves the utilization of atoms,significantly increases the number of electrically active centers,and improves the catalysis of H2O2.BNC,designed with sodium chloride as the loading dispersion material of Pt Pd Cu MBNS,is a microporous product with high density of electronic states and a large number of free electrons,which can further catalyze and enrich H2O2.Due to the additional transport channel provided by the hollow pyrolysis micro-ZIF-8 and the uniform growth of gold nanoparticles in situ,Au@SNHC realizes high-performance electronic transmission,mass transfer and Ab1fixation,and significantly enhances the signal transmission of the whole system.Under the optimized conditions,the designed immunosensor realized the sensitive detection of c Tn I,with good stability,reproducibility and selectivity.The linear detection range is 10 fg mL-1～100 ng mL-1,and the detection limit is 4.27 fg mL-1. |
