Polyaniline (PANI), an attractive conductive polymer, has been successfully applied in fabricating various types of enzyme-based biosensors. In this study < we have synthesized mesoporous silicates SBA-15 using nonionic block copolymers and stably entrapped horseradish peroxidase (HRP) , and then deposited the loaded SBA-15(or SBA-15(HRP))on the PANI modified platinum(Pt) electrode to construct a GA/SBA-15(HRP)/PANI/Pt biosensor for the detection of hydrogen peroxide(H2O2). The mesoporous structure and morphology of unloaded and loaded SBA-15 were assesses by X-ray diffraction(XRD),transmission electron microscopy (TEM), scanning electron microscopy (SEM),N2 adsorption-desorption isotherm , and Brunauer-Emmett-Teller (BET) calculation. Protein assay and ABTS enzymatic assay were employed to evaluate the immobilization efficiency. Our resulted demonstrated that the mesoporous SBA-15 provided large surface area (>700m2/g) and suitable pore diameter (80~100A) for HRP immobilization.
Meanwhile, the entrapped HRP did not significantly deform the structure of SBA-15 but retained its bioactivity. The cyclic voltammogram (CV) of constructed GA/SBA-15(HRP)/PANI/Pt biosensor also displayed a fine linear correlation between cathdodic response and H2O2 in the range of 0.02 to 40 mM(R2=0.999) with enhanced sensitivity (87.96 μA·mM-1·cm-2). In particular, this approach by utilizing SBA-15 to entrap HRP allowed the PANI modified biosensor to be performed with multiple measurements as the result of improved stability.
