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A sandwich-type electrochemical immunosensor was designed for quantitative detection of prostate specific antigen (PSA). Gold-platinum bimetallic functionalized tin oxide graphene (GS-SnO2-Au@Pt) has a large specific surface area, good conductivity and biocompatibility, which was used as the sensing interface to capture PSA coating antibody (Ab1). The copper ions doped Ag-Au nanospheres (Cu2+@Ag-Au) was prepared and used as a label of PSA labeling antibody (Ab2), which generated high intensive electrochemical redox signal based on the reduction reaction of Cu2+. The L-cysteine was applied as a bridge to connect Au nanoparticles (NPs) and Ag NPs, and to keep the nanosized gap between Au nuclear and Ag shell. This structure not only makes full advantage of space effect to load more Ag NPs but also increases the specific surface area for loaded more Cu2+. The proposed immunosensor with a wide range (10 pg mL[?]1 to 100 ng mL[?]1) and a low detection limit (3.84 pg mL[?]1) shows excellent performance in the detection of PSA. The results indicate that proposed immunosensor provides a promising application for the quantitative detection of biomolecules in serum samples.

Polytetraphenylporphyrin Co(II) (PTPPCo) is obtained by heat-treating 5,10,15,20-tetra(4-carboxyphenyl)-porphyrin Co(II) at in an argon atmosphere. Thermogravimetric analysis is used to evaluate the thermal stability of PTPPCo. Oxidation resistance of PTPPCo is measured by refluxing in Fentons reagent for . The ultraviolet-visible spectra indicate that PTPPCo is not decomposed and cobalt ion is not exfoliated. Polytetraphenylporphyrin is obtained by the heat-treatment of PTPPCo, which is adsorbed on Vulcan XC-72 with loading, at in an Ar atmosphere. Cyclic voltammetry, linear sweep voltammetry, and chronoamperometry tests are performed in order to observe the catalyst durability in different conditions. Almost no performance deficiency is observed after 10,000 continuous voltammetric cycles, 200 potentiometric cycles, and of chronoamperometry test. catalysts display significant chemical stability and electrocatalytic durability. These catalysts may be useful for polymer electrolyte membrane fuel cells.