Construction of a turn off-on fluorescent nanosensor for cholesterol based on fluorescence resonance energy transfer and competitive host-guest recognition

• Published in: Talanta (Oxford) 2019-08, Vol.201, p.82-89
• Main Authors: Li, Yuehai, Cai, Jiabai, Liu, Fengjiao, Yang, Hui, Lin, Ye, Li, Shunxing, Huang, Xuguang, Lin, Luxiu
• Format: Article
• Language: English
• Subjects: Au nanoparticles; Carbon quantum dots; Cholesterol; Fluorescence resonance energy transfer; Host-guest recognition; β-cyclodextrin
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.03.110

Using chloroauric acid as precursor and β-cyclodextrin (β-CD) as reducing agent and stabilizer, β-CD@AuNPs with negative charge were synthesized by one-step colloidal synthesis method. The positive charged carbon quantum dots (CQDs) were synthesized by one-step of sonication of cetylpyridinium chloride. Under the role of static electricity, the fluorescence resonance energy transfer (FRET) occurred between CQDs and β-CD@AuNPs. CQDs and β-CD@AuNPs served as the fluorescence energy donors and receptors, respectively, i.e., the fluorescence of CQDs was turned off by β-CD@AuNPs. Based on the specific host-guest recognition between the inner cavity of β-CD and cholesterol, CQDs was replaced by cholesterol, the FRET could be interrupted, and then the fluorescence of CQDs was turned on. A good linear relationship between cholesterol concentration (10–210 μmol L−1) and fluorescence intensity was obtained and the LOD was 343.48 nmol L−1. Because of excellent fluorescence quenching ability of FRET, the analytical performance (including LOD and linear scope) of such a turn off-on fluorescent nanosensor (e.g., CQDs/β-CD@AuNPs) was better than nanosensor only via competitive host-guest recognition (e.g., β-CD functionalized CQDs). The synergistic effect of competitive host-guest recognition and FRET was proved. Because of selective recognition, ultrasensitive, wide linear range, and strong anti-interference ability, CQDs/β-CD@AuNPs as a turn off-on fluorescent nanosensor was developed to determine cholesterol in porcine serum. [Display omitted] •A novel turn off-on fluorescent nanosensor for cholesterol was constructed.•A convenient and environment friendly method to detect cholesterol was proposed.•Analytical performance is improved by FRET and competitive host-guest recognition.•Fluorescence energy donor and receptor have opposite charge and the same spectral peak.•LOD and linear scope for cholesterol are 343.48 nmol L−1 and 10–210 μmol L−1.