Direct synthesis of metal oxide incorporated mesoporous SBA-15, and their applications in non-enzymatic sensing of glucose

One-step direct synthetic route is reported for the preparation of M-SBA-15 materials (M=Cu, Ni, Co, Fe, and Mn) with nSi/nM ratios ranging from 100 to 10 under mild acidic condition than conventionally employed for the synthesis of Si-SBA-15. Materials were characterized by a complementary combination of X-ray diffraction, nitrogen sorption, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, and UV-visible spectroscopy. Experimental evidences show that metal oxides are incorporated in the pore wall of SBA-15 matrices. A non-enzymatic electrochemical sensor device was fabricated for glucose detection based on M-SBA-15 materials. Cyclic voltammetry and linear sweep voltammetry were used to evaluate the catalytic activity of the M-SBA-15 modified electrode toward glucose. It was found that the Cu-SBA-15 (Si/Cu=20) modified electrode showed enhanced electrocatalytic activity toward the oxidation of glucose in alkaline solution compared to that of the conventional CuO and other M-SBA-15 materials investigated in this study. Under the optimal detection conditions, the Cu-SBA-15 (Si/Cu=20) exhibited linear behavior in the concentration range from 10 μM to 20 mM for the quantification of glucose with a limit of detection of 10 μM. Moreover, the Cu-SBA-15 modified electrode was also relatively insensitive to commonly interfering species such as ascorbic acid, uric acid, and dopamine.

Thermally Stable Improved First-Generation Glucose Biosensors based on Nafion/Glucose-Oxidase Modified Heated Electrodes

We illustrate how the use of heated electrodes enhances the performance of glucose biosensors based on amperometric detection of the glucose-oxidase generated hydrogen peroxide. Nafion is shown to be an excellent matrix to protect glucose oxidase from thermal inactivation during the heating pulses. The influence of the electrode temperature upon the amperometric response is examined. Temperature pulse amperometry (TPA) has been used to obtain convenient peak-shaped analytical signals. Surprisingly, up to 67.5 °C, the activity of Nafion-entrapped glucose oxidase is greatly enhanced (24 -fold) by accelerated kinetics rather than decreased by thermal inactivation. Amperometric signals even at elevated temperatures are stable upon prolonged operation involving repetitive measurements. The linear calibration range is significantly extended.