Mesoporous MnO2 as enzyme immobilization host for amperometric glucose biosensor construction

Mesoporous MnO₂ (mesoMnO₂) is synthesized facilely through sol–gel process using nonionic surfactant polyxyethylene fatty alcohol (AEO₉) as template. Transmission electron microscopy (TEM) image and N₂ adsorption/desorption isotherm show that the obtained mesoMnO₂ material presents disordered porous structure and appropriate pore size suitable for the immobilization of glucose oxidase (GOx). An amperometric glucose biosensor based on GOx entrapped in mesoMnO₂ is fabricated, in which mesoMnO₂ also acts as a catalyst for the electrochemical oxidation of H₂O₂ produced by enzyme reaction. The biosensor shows fast and sensitive current response to glucose in the linear range of 0.0009–2.73 mM. The response time (t_95%) is less than 7 s. The sensitivity and detection limit are 24.2 μA cm⁻² mM⁻¹ and 1.8 × 10⁻⁷ M (S/N = 3), respectively. This indicates that mesoMnO₂ has promising application in enzyme immobilization and biosensor construction.