A novel strategy for immobilization of thionine based on calcium carbonate-gold nanoparticles inorganic hybrid composite and its application in hydrogen peroxide sensor

Abstract

A novel strategy for efficient immobilization of electroactive Thionine (Th) on the gold (Au) electrode surface based on calcium carbonate-gold nanoparticles (CaCO3-AuNPs) inorganic hybrid composite was proposed and conducted by the strong electrostatic interaction between positively charged Th and negatively charged CaCO3-AuNPs composite. The hybrid composite was obtained by the adsorption of AuNPs onto the surface of CaCO3 microspheres through electrostatic interaction. Due to the microporous architecture, large surface area, and good biocompatibility of CaCO3-AuNPs composite, the amount and stability of the immobilized Th were highly strengthened. The application of the resulting Th modified electrode in the hydrogen peroxide (H2O2) sensor was also investigated. It exhibited rapid response to H2O2 within 3 s. The linear calibration ranged from 8.00 × 10−7 to 1.06 × 10−3 mol/L with a detection limit of 2.00 × 10−7 mol/L.