AUTHOR=Wan Yejian , Zhao Jingwen , Deng Xiaochun , Chen Jie , Xi Fengna , Wang Xiaobo 

TITLE=Colorimetric and Fluorescent Dual-Modality Sensing Platform Based on Fluorescent Nanozyme

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.774486

DOI=10.3389/fchem.2021.774486

ISSN=2296-2646

ABSTRACT=Comparing to natural enzymes, nanozymes based on carbonaceous nanomaterials are advantages due to high stability, good biocompatibility, and possibility of multifunctionalities through materials engineering at atomic level. Herein, we present a sensing platform using nitrogen doped graphene quantum dot (NGQD) as highly efficient fluorescent peroxidase mimic, which enable colorimetric/fluorescent dual-modality platform for detection of hydrogen peroxide (H2O2) and biomolecules (ascorbic acid-AA, acid phosphatase-ACP) with high sensitivity. NGQD is synthesized using a simple hydrothermal process, which has advantages of high production yield and potential for large-scale preparation. NGQD with uniform size (3.0 nm ± 0.6 nm) and single-layer graphene structure exhibits bright and stable fluorescence. N-doping and ultrasmall size endow NGQD with high peroxidase-mimicking activity with obviously reduced Michaelis-Menten constant (Km) in comparison with natural horseradish peroxidase (HRP). Taking advantages of both high nanozyme activity and unique fluorescence property of NGQD, a colorimetric and fluorescent dual-modality platform capable of detecting H2O2 and biomolecules (AA, ACP) with high sensitivity is developed as the proof-of-concept demonstrations. Furthermore, the mechanisms underlying the nanozyme activity and biosensing are investigated.