Non-Redox Modulated Fluorescence Strategy for Sensitive and Selective Ascorbic Acid Detection with Highly Photoluminescent Nitrogen-Doped Carbon Nanoparticles via Solid-State Synthesis

Abstract

Highly photoluminescent nitrogen-doped carbon nanoparticles (N-CNPs) were prepared by a simple and green route employing sodium alginate as a carbon source and tryptophan as both a nitrogen source and a functional monomer. The as-synthesized N-CNPs exhibited excellent water solubility and biocompatibility with a fluorescence quantum yield of 47.9%. The fluorescence of the N-CNPs was intensively suppressed by the addition of ascorbic acid (AA). The mechanism of the fluorescence suppression of the N-CNPs was investigated, and the synergistic action of the inner filter effect (IFE) and the static quenching effect (SQE) contributed to the intensive fluorescence suppression, which was different from those reported for the traditional redox-based fluorescent probes. Owing to the spatial effect and hydrogen bond between the AA and the groups on the N-CNP surface, excellent sensitivity and selectivity for AA detecting was obtained in a wide linear relationship from 0.2 μM to 150 μM. The detection limit was as low as 50 nM (signal-to-noise ratio of 3). The proposed sensing systems also represented excellent sensitivity and selectivity for AA analysis in human biological fluids, providing a valuable platform for AA sensing in clinic diagnostic and drug screening.

Nitrogen-doped Carbon Dots Mediated Fluorescent on-off Assay for Rapid and Highly Sensitive Pyrophosphate and Alkaline Phosphatase Detection

“…In the FT-IR analysis of N-CDs, the following were observed: stretching vibration of O–H at 3408 cm −1 and C–H at 2930 cm −1 , stretching vibration and bending vibration of N–H at 3256 cm −1 and 1586 cm −1 , bending vibration of the C–O at 1401 cm −1 and the stretching peak of C–O–C at 1111 cm −1 , C–N stretching vibration at 1246 cm −1 (Fig. 1d) 43–45 . These results indicate that there are abundant of hydroxyl, amino and carboxyl group on the surface of the N-CDs.…”

“…The N-CDs were prepared by a green and facile solid phase method according to a previously reported method with minor modification 43 . Briefly, tryptophan (10 mmol, 2.04 g) and sodium alginate (1.08 g) were mixed and ground to a uniform powder in an agate mortar.…”

Applications of graphene and its derivatives in intracellular biosensing and bioimaging

“…3 Since graphene, GO, and rGO exhibit excellent mechanical, electrical, thermal and optical properties, these two-dimensional (2D) materials are attracting increasing attention and they are under active research. 7,8 Recently, a combination of graphene and imaging science approaches has led to the generation of graphene-based bioimaging probes for biosensing and bioimaging. Bioimaging is one crucial biotechnology aimed at developing novel methods to image specific molecular pathways in living cells or human body, particularly in disease processes.…”

Phosphomolybdic acid functionalized graphene loading copper nanoparticles modified electrodes for non-enzymatic electrochemical sensing of glucose

“…In recent years, a variety of nanomaterials [3,4], especially the carbon-based nanocomposites [5][6][7][8], have been introduced to the fabrication of non-enzymatic electrochemical glucose sensors due to their desirable chemical, physical and electronic properties, which can enhance the sensing performance. Among these M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 materials, graphene-based nanocomposites [9][10][11] have aroused extensive interest and become attractive choices for glucose non-enzymatic sensing.…”