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

Core/shell nanoparticles consisting of a Fe(3)O(4) nanoparticle core and a mesoporous silica shell (Fe(3)O(4)/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 x 10(-7) M, at a signal-to-noise ratio of 3, and a sensitivity of 84.4 mu A mM(-1) cm(2).