Composite soft-template method synthesis and biosensing application of hedgehog-like bismuth sulfide micro-nanostructures

Taking a novel composite soft-template combining a cationic surfactant CTAB and trimellitic acid, the uniform hedgehog-like bismuth sulfide micro-nanostructures were successfully fabricated through a hydrothermal method, using Bi(NO3)3 as a bismuth source and thiourea as a sulfur source to slowly release S2− ions. The as-synthesized hedgehog-like bismuth sulfide micro-nanostructures, taking the outer diameter size of about 4 μm, were assembled by Bi2S3 thin nanorods possessed nano-scale cross-section. The length of Bi2S3 thin nanorods is up to 2 μm and the tip diameter size is around 50 nm, compared to the larger root diameter. XRD characterization of the as-prepared hedgehog-like bismuth sulfide nanomaterial testified its quadrature-phase crystal. The effects of the concentrations of reactants and additives on the morphology and size of Bi2S3 particles were studied and the possible formation mechanism of the hedgehog-like Bi2S3 micro-nanostructures was explored. The resulting hedgehog-like bismuth sulfide sample was employed to manufacture immune sensor and the testing result indicated that micro-nanostructures could not only enhance reaction current by employing the electrode reduction of hydrogen peroxide thionine by a HRP catalysis, but also the catalytic current intensity was linearly proportional to the AFP concentration in the range of 0.01∼20 ng/mL, with a linear correlation coefficient of 0.9974 and a slope of 0.2878. It is worth mentioning that the proposed-manner can be applied to detect serum AFP antigen.