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A ratiometric fluorescence sensor for ultra-sensitive detection of trypsin inhibitor in soybean flour using gold nanocluster@carbon nitride quantum dots
- Hu, Xuetao, Shi, Jiyong, Shi, Yongqiang, Li, Wenting, Arslan, Muhammad, Zhang, Wen, Huang, Xiaowei, Li, Zhihua, Xu, Yiwei, Li, Yanxiao, Zou, Xiaobo
- Analytical and bioanalytical chemistry 2019 v.411 no.15 pp. 3341-3351
- bovine serum albumin, carbon nitride, detection limit, fluorescence, gold, heat treatment, hydrolysis, nanocomposites, nanogold, quantum dots, sensors (equipment), soy flour, trypsin, trypsin inhibitors
- Gold nanocluster@carbon nitride quantum dot nanocomposites protected by bovine serum albumin (BSA-AuNC@CNQDs) were designed as a ratiometric fluorescence nanosensor for ultra-sensitive detection of trypsin inhibitor (TI). CNQDs were prepared via thermal treatment of carbon nitride powder. BSA-CNQDs acted as templates to synthesize BSA-AuNC@CNQDs with dual-emission peaks at 450 and 650 nm. Trypsin can catalyze the hydrolysis of BSA and decompose BSA-AuNC@CNQDs resulting in fluorescence quenching. The fluorescence quenching at 650 nm was prevented by the addition of TI to inhibit the activity of trypsin. The nanosensor-trypsin system showed a satisfactory ability toward TI detection. The ratiometric responses (the ratio of intensity at 650 to 450 nm, I₆₅₀/I₄₅₀) had an excellent linearity (R² = 0.981) with logarithmic values of TI concentrations in the broad range of 1–10,000 ng/mL. The limit of detection (LOD, 0.089 ng/mL) indicates ultra-sensitive detection of TI can be achieved. Additionally, TI in soybean flour was detected by the proposed ratiometric method with satisfactory recoveries (98.15–105.52%) and less than 6% of coefficient of variation. This study reveals that BSA-AuNC@CNQDs have potential applications in detection of TI in real samples.