Synthesis of highly fluorescent P,O-g-C sub(3)N sub(4) nanodots for the label-free detection of Cu super(2+) and acetylcholinesterase activity

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 3; no. 41; pp. 10916 - 10924
• Main Authors: Rong, Mingcong, Song, Xinhong, Zhao, Tingting, Yao, Qiuhong, Wang, Yiru, Chen, Xi
• Format: Journal Article
• Language: English
• Published: 01.10.2015
• Subjects: Etching; Fluorescence; High resistance; Linearity; Melamine; Nanostructure; Phytic acid; Quenching
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c5tc02584b

Highly fluorescent phosphorus, oxygen-doped graphitic carbon nitride nanodots (P,O-g-C sub(3)N sub(4) nanodots) were synthesized using chemical oxidation and hydrothermal etching of bulk P-g-C sub(3)N sub(4) obtained via pyrolysis of phytic acid and melamine. The P,O-g-C sub(3)N sub(4) nanodots emitted strong blue fluorescence with a high quantum yield of 90.2%, and displayed high resistance to photobleaching and high ionic strength. A sensitive and facile fluorescence sensing approach for Cu super(2+) was developed through fluorescence quenching based on the static fluorescence quenching and photoinduced electron transfer. Under optimal conditions, a rapid detection of Cu super(2+) could be completed in 5 min with a detection limit of 2 nM, and a linearity ranging from 0 to 1 mu M. Using acetylthiocholine (ATCh) as the substrate, the fluorescence of the P,O-g-C sub(3)N sub(4) nanodots-Cu super(2+) system could be sensitively turned on in the presence of acetylcholinesterase (AChE) through the reaction between Cu super(2+) and thiocholine, the hydrolysis product of ATCh by AChE. A linearity ranging from 0.01 to 3 mU mL super(-1) could be obtained with a detection limit of 0.01 mU mL super(-1). In addition, the proposed approach showed potential application for the detection of Cu super(2+) in natural water samples and AChE activity in human plasma.