In this study, we developed a sensitive and selective sensing system for the detection of metallothioneins (MTs). The system is based on the fluorescence resonance energy transfer (FRET) between carbon quantum dots (CQDs) and gold nanoparticles (AuNPs). In this method, the fluorescence emission of CQDs was quenched by AuNPs due to FRET. When MTs were added to the CQD-AuNP system, the strong combination between thiol group and Au made the CQDs release from AuNPs, and the fluorescence of CQDs was recovered. The CQD-AuNP system can detect the MTs in aqueous solution (pH 3.0, citrate-HCl buffer) selectively and sensitively with a short response time (15 min). Results show that the fluorescence recovery efficiency has a good linear relationship with the MTs concentration in the range of 12-210 nmol L-1, and the limit of detection was 5.25 × 10-9 mol L-1. Furthermore, the sensing system was utilized to determine MTs in human urine samples with satisfactory results. The proposed system exhibits the advantages of high sensitivity, high selectivity, easy operation and most importantly, low cost and non-cytotoxicity to detect protein MTs.

中文翻译：

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基于碳量子点和金纳米粒子的金属硫蛋白灵敏选择性传感系统

在这项研究中，我们开发了一种用于检测金属硫蛋白 (MT) 的灵敏且选择性的传感系统。该系统基于碳量子点 (CQD) 和金纳米粒子 (AuNP) 之间的荧光共振能量转移 (FRET)。在该方法中，由于 FRET，CQD 的荧光发射被 AuNPs 淬灭。当在 CQD-AuNP 体系中加入 MTs 时，巯基与 Au 之间的强结合使 CQDs 从 AuNPs 中释放出来，CQDs 的荧光得到恢复。CQD-AuNP 系统可以选择性且灵敏地检测水溶液（pH 3.0，柠檬酸盐-HCl 缓冲液）中的 MT，响应时间短（15 分钟）。结果表明，荧光回收效率在12-210 nmol L-1范围内与MTs浓度呈良好的线性关系，检测限为5。25 × 10-9 mol L-1。此外，该传感系统用于测定人体尿液样本中的 MT，结果令人满意。所提出的系统具有高灵敏度、高选择性、易于操作的优点，最重要的是，检测蛋白质 MT 的成本低且无细胞毒性。