Fluorescent enzyme-linked immunoassay based on silane-doped carbon dots for sensitive detection of microcystin-LR in water and crucian samples

• Published in: The Science of the total environment 2020-03, Vol.708, p.134614-134614, Article 134614
• Main Authors: Xu, Zhen-Lin, Ye, Song-Ling, Luo, Lin, Hua, Xiude, Lai, Jing-Xian, Cai, Xiang-Ping, Liang, Qing-Wen, Lei, Hong-Tao, Sun, Yuan-Ming, Chen, Yi-ping, Shen, Xing
• Format: Article
• Language: English
• Subjects: 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate); Animals; Carbon; Carps; Enzyme-Linked Immunosorbent Assay; Fluorescence; Fluorescent enzyme-linked immunosorbent assay; Hydrogen Peroxide; Microcystin-LR; Microcystins; Silane carbon dots; Silanes; Water
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.134614

[Display omitted] •Fluorescent nanoparticles labeling-free immunoassay for MC-LR was developed.•Fluorescence quenching of silane-doped carbon dots was used as analytical signal.•The assay can determine MC-LR at 0.6 ng L−1 for water and fish samples.•The assay is an ideal screening tool for determination of MC-LR. In this work, a fluorescent nanoparticles labeling-free fluorescence enzyme-linked immunoassay (FELISA) has been established for the ultrasensitive detection of microcystin-LR (MC-LR) in water and fish samples. Polyclonal antibody against MC-LR was labeled with horseradish peroxidase (HRP) and used as signal probe for binding with analyte in sample or for coating antigen. After washing of the unbound antibody, the substrate system (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS)/H2O2) was added. The oxidation product of ABTS (ox-ABTS) catalyzed by HRP effectively caused the fluorescence quenching of subsequently added silane-doped carbon dots (Si-CDs), and the change in fluorescence intensity of Si-CDs was used to realize the quantitative detection of MC-LR. Under the optimum conditions, the Si-CDs based FELISA method showed a good linear relationship from 0.001 to 3.20 μg L−1 (R2 = 0.994) and provided a low detection limit of 0.6 ng L-1, which was approximately 30-fold lower than that of traditional indirect competitive ELISA. Average recovery values from 79.9% to 109.2% was obtained from spiked water and crucian samples, suggesting its potential application on the monitoring of MR-LR at a trace level.