Colorimetric biosensing of glucose in human serum based on the intrinsic oxidase activity of hollow MnO2 nanoparticles
Colorimetric analysis is a method for determining the concentration of a chemical compound in a solution using a color reagent. Here, we developed a low cost and rapid approach for cascade biosensing of glucose in human serum samples by taking into account the advantages of the excellent selectivity of natural glucose oxidase and the splendid catalytic properties of nanozymes. Hollow manganese dioxide nanoparticles (H-MnO2 NPs) assembled by abundant nanosheets were successfully synthesized via a one-pot reduction strategy, demonstrating exhibited splendid oxidase-like activities. In the colorimetric analysis system, glucose oxidase can oxidize glucose to produce H2O2, which can consume the proposed H-MnO2 NPs in acid medium. Then, the residual H-MnO2 NPs can catalyze the 3,3′,5,5′-tetramethylbenzidine molecules and then produce a colorimetric signal at 652 nm, which can quantificationally reflect the concentrations of glucose. The lower limit of detection of glucose is 0.84 μM and the system has a linear response up to 200 μM. This method provides suitable specificity and practical feasibility to be used for the routine analysis of human serum samples.
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