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

Abstract

Compared with natural enzymes, nanozymes based on carbonaceous nanomaterials are advantages due to high stability, good biocompatibility, and the possibility of multifunctionalities through materials engineering at an atomic level. Herein, we present a sensing platform using a nitrogen-doped graphene quantum dot (NGQD) as a highly efficient fluorescent peroxidase mimic, which enables a 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 ± 0.6 nm) and a single-layer graphene structure exhibits bright and stable fluorescence. N-doping and ultrasmall size endow NGQD with high peroxidase-mimicking activity with an obviously reduced Michaelis–Menten constant (Km) in comparison with natural horseradish peroxidase. 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 demonstration. Furthermore, the mechanisms underlying the nanozyme activity and biosensing are investigated.

Colorimetric and Fluorescence Dual-Mode Biosensors Based on Peroxidase-Like Activity of the Co3O4 Nanosheets

“…Additionally, the colorimetric product oxTMB can effectively quench the fluorescence emitted by Ru (bpy) 3 2+ due to the IFE. Thus, glucose also can be indirectly detected by the fluorescence method which can not only improve detection sensitivity but also avoid the false positives caused by a single colorimetric signal response ( Shin et al, 2020 ; Munzi et al, 2021 ; Wan et al, 2021 ).…”

Electrochemical Sensor Nanoarchitectonics for Sensitive Detection of Uric Acid in Human Whole Blood Based on Screen-Printed Carbon Electrode Equipped with Vertically-Ordered Mesoporous Silica-Nanochannel Film

“…As a class of biomarkers, metabolites are the metabolic product of natural life activities in an organism. Reliable and sensitive detection of metabolites plays an important role in the diagnosis and prevention of diseases [ 1 , 2 , 3 , 4 , 5 ]. For instance, uric acid (UA), as the purine metabolic product, is related to many clinical diseases including renal dysfunction, chronic nephritis, renal insufficiency, gout, and cardiovascular disease, etc.…”

Vertically-Ordered Mesoporous Silica Films Grown on Boron Nitride-Graphene Composite Modified Electrodes for Rapid and Sensitive Detection of Carbendazim in Real Samples

“…Arising from the high density of silanol groups on the channel walls and ultrasmall size of channels, molecular selectivity, and performance of VMSF could be modulated by modification of functional groups and confined growth of nanomaterials, broadening its practical applications (Lu et al, 2018;Yan et al, 2020a). For example, graphene quantum dots (GQD), a 0D graphene materials (Yan et al, 2019), are characterized by an atomically thin planar carbon structure with ultrasmall size (He et al, 2019;Mao et al, 2019), abundant active sites (Kaixin Li et al, 2018;Ge et al, 2019;Wan et al, 2021), tunable chemicophysical properties (Nan Li et al, 2018;Pang et al, 2018;Yan et al, 2018), and efficient heterogeneous electron transfer capacity (Huang et al, 2018;Tian et al, 2018;Gong et al, 2021a), could be confined into the nanochannels of VMSF to serve as the recognition, enrichment, and catalysis element, leading to the ultrasensitive electrochemical analysis of heavy metal ions and neurotransmitter in complex real samples (Lu et al, 2018). Currently, VMSF supported by indium tin oxide (ITO) electrode is rather stable and could be fabricated by using electrochemically-assisted self-assembly (EASA) and Stöbersolution approaches (Zhou et al, 2019;Walcarius, 2021).…”