Cellulose nanofibrils/carbon dots composite nanopapers for the smartphone-based colorimetric detection of hydrogen peroxide and glucose

초록

Fe-doped carbon dots (FeCDs) with high peroxidase (POD)-like activity were prepared by a rapid microwave-assisted method and immobilized on cellulose nanofibrils (CNF) to produce a composite nanopaper. The POD activity of the nanopaper was evaluated by the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) and applied to the colorimetric detections of hydrogen peroxide (H2O2) and glucose. CNF acted as a support for the nanozyme, thus imparting it with reusability. It also adsorbed the chromogen during the reaction to induce a color change, thus acting as a test strip for portable on-site detection. A smartphone was employed to monitor this color change which made the whole detection process simple and economical. Under optimal conditions, this method afforded linear ranges of 6-42 mu M and 10-70 mu M and detection limits of 0.93 and 1.73 mu M for the H2O2 and glucose, respectively. The results of the quantification of glucose in human serum samples were comparable to those of the standard glucose oxidase (GOD)-POD method. Further, the nanopaper was potentially reused for ten cycles and presented over a month of shelf life.

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