A novel immunosensor for detection of beta-galactoside alpha-2, 6-sialyltransferase in serum based on gold nanoparticles loaded on Prussian blue-based hybrid nanocomposite film

• For the first time, a sensitive ST6Gal-I electrochemical immunosensor was developed.
• PB-based hybrid conductive nanocomposite was synthesized utilizing a simple method.
• The developed immunosensor possessed excellent sensitivity and selectivity.
• The proposed immunosensor was successfully applied for the analysis of ST6Gal-I in serum samples.

In this paper, we presented a novel electrochemical immunosensor using gold nanoparticles (AuNPs) loaded on the Prussian blue (PB)-based hybrid nanocomposite film that sensitively detects β-galactoside α-2, 6-sialyltransferase (ST6Gal-I). The immunosensor was fabricated based on a Prussian blue-based (PB) hybrid nanocomposite, consisting 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, 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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