Core/shell nanoparticles as hybrid platforms for the fabrication of a hydrogen peroxide biosensor

Abstract

Core/shell nanoparticles consisting of a Fe₃O₄ nanoparticle core and a mesoporous silica shell (Fe₃O₄/m-silica) were used as a matrix for immobilization of horseradish peroxidase (HRP) enzyme and subsequent design of an amperometric hydrogen peroxide biosensor. HRP enzyme was immobilized on the core/shell nanoparticles through the electrostatic interaction between oppositely charged HRP enzyme and the silica shell at neutral pH. The enzyme–core/shell nanoparticle hybrid material was deposited on screen printed electrodes and further characterized by ultraviolet–visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). This set up was used as a biosensor to detect hydrogen peroxide. The hydrogen peroxide biosensor showed a detection limit of 4.3 × 10⁻⁷ M, at a signal-to-noise ratio of 3, and a sensitivity of 84.4 μA mM⁻¹ cm².