| In recent years, electrochemical immunosensor has been selected as an ideal analysis strategy for biomarkers and it has been widely applied in the clinical diagnostics and biological samples analysis due to its high selectivity, high sensitivity and low-cost. With the development of nanotechnology, the electroactive nanocomposites and metals nanoparticles have potential application in constructing electrochemical immunosensor owing to their unique electrochemical properties and good biocompatibility. Given these advances, we presented a novel electrochemical immunosensor using noble gold nanoparticles (AuNPs) loaded on the Prussian blue (PB)-based hybrid nanocomposite film that sensitively detects β-galactoside a-2, 6-sialyltransferase (ST6Gal-I). The Prussian blue-based (PB) hybrid nanocomposite served as the biosensing platform, which consists of graphene oxide (GO), multi-walled carbon nanotubes (MWCNTs), PTA (a derivative of 3,4,9,10-perylenetetracarboxylicdianhydride, PTC-NH2) and chitosan (CS). With the assistance of the abundance of amino groups from CS and PTA, AuNPs were densely adsorbed onto the surface of the nanocomposite through the strong interaction between -NH2 and Au, providing a large available surface area for the immobilization of abundant anti-ST6Gal-I. As measured by cyclic voltammogram (CV) and differential pulse voltammogram (DPV), PB served as an electroactive and biocompatible redox probe in achieving electrochemical signal. Under the optimal detection conditions, the immunosensor exhibited a good linear response to ST6Gal-I in the range from 0.01 to 250 ng mL"1 and a lower detection limit of 3 pg mL-1 (S/N=3). Furthermore, the method was successfully applied to analyze ST6Gal-I from human serum samples and yielded satisfactory results. In conclusion, our prepared immunosensor presented a high sensitivity and excellent selectivity to ST6Gal-I, indicating its potential in future clinical and experimental analysis. |
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