Chemically modified carbon nitride-chitin-acetic acid hybrid as a metal-free bifunctional nanozyme cascade of glucose oxidase-peroxidase for “click off” colorimetric detection of peroxide and glucose

Publication date: Available online 4 February 2020Source: Biosensors and BioelectronicsAuthor(s): Pavel Sengupta, Krishnendu Pramanik, Pallab Datta, Priyabrata SarkarAbstractHybrid nanomaterials-based artificial enzymes with numerous utilities are necessary to develop future bionic devices in mimicking physiological processes. This paper demonstrates bifunctional enzyme mimicking roles of a metal-free nanozyme hybrid of chemically modified graphitic carbon nitride (MGCN), chitin and acetic acid (AcOH). The MGCN exhibited glucose oxidase-mimicking activity and chitin-AcOH mirrored peroxidase. MGCN-chitin-AcOH when in contact with glucose, oxidised glucose to gluconic acid and hydrogen peroxide (H2O2) while the chitin-AcOH decomposed the generated H2O2, as proved separately, by concurrent oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). The super-sensitive colorimetric process produced linear regression equation for H2O2 as A = 0.00105C + 0.0630 (C:μM, R2 = 0.9961) with a detection limit of 0.052 μM, whereas for glucose, the linear relationship was A = 0.00084C + 0.0458 (C:μM, R2 = 0.9952) having a detection limit of 0.055 μM. The developed method was also successfully applied for assessment of H2O2 and glucose in human serum and urine samples. Non-enzymatic glucose test strips from MGCN-chitin-AcOH based hydrogel were reported and verified for semi-quantitative analysis of glucose. These compared well with results from standard enzyme-based colorimet...
Source: Biosensors and Bioelectronics - Category: Biotechnology Source Type: research