Synthesis of highly fluorescent P,O-g-C 3 N 4 nanodots for the label-free detection of Cu 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: 2015
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/C5TC02584B

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