Mesoporous silica hollow sphere (MSHS) for the bioelectrochemistry of horseradish peroxidase

In this work, novel mesoporous silica hollow spheres (MSHS) were chosen as an immobilization matrix, to construct a mediator-free third-generation HRP biosensor. UV-vis spectroscopy revealed that horseradish peroxidase (HRP) entrapped in MSHS could retain its native Structure. FTIR spectroscopy and nitrogen adsorption-desorption isotherms indicated that HRP are intercalated into the mesopores. The direct electron transfer of HRP entrapped in MSHS was observed. A pair of stable and well-defined redox peaks of HRP with a formal potential of about -0.150V (vs. Ag/AgCl) in 0.1 M pH 7.0 phosphate-buffered solution (PBS) were obtained. The biosensor exhibited a fast amperometric response to H2O2 with a linear range of 3.9 x 10(-6) to 1.4 x 10(-4) M (R = 0.997, N = 20). The detection limit was 1.2 x 10(-6) M based S/N = 3. (C) 2008 Published by Elsevier B.V.