Exploration of enzyme-MnO₂ nanosheets hybridization probe for sensitively colorimetric self-indicating of glucose

A colorimetric self-indicating probe for glucose was constructed by self-assembly of MnO₂ nanosheets(MnO₂ NSs)and glucose oxidase(GOD)in this paper. Under the weak acidic medium, glucose oxidase specifically catalyzes glucose into gluconic acid and hydrogen peroxide. The by-product of hydrogen peroxide could efficiently dissolve the MnO₂ nanosheets, resulting into a significant decrease of the characteristic absorbance at 374 nm assigned to MnO₂ NSs. Furthermore, the absorbance difference was linearly proportional to the concentration of glucose ranging from 1 to 20 μmol/L. The fitted curve could be used for quantification of glucose with a correlation coefficient of 0. 990 1. And the detection limit as low as 0. 1 μmol/L could be reached based on the definition of three times of the deviation of the blank signal(3σ)and there was negligible interference with other co-existing amino acids, anions, cations and protein, which indicated high sensitivity and selectivity of the hybrid probe. The construction strategy of designated probe is readily generalized in principle for detection of numerous analytes in view of reactive property of MnO₂ and the diversity of enzymes.