Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India 695 012.
Analyst. 2011 Mar 7;136(5):933-40. doi: 10.1039/c0an00424c. Epub 2010 Dec 13.
This paper reports the use of fluorescent gold nanoclusters synthesized using bovine serum albumin (Au-BSA) for the sensing of copper ions in live cells. The fluorescence of the clusters was found to be quenched by Cu(2+) enabling its detection in cells. The selectivity of the nanosensor was demonstrated in the presence of several cations excluding Hg(2+). We did not study the effect of Hg(2+) since it was reported earlier. The present study suggests that Cu(2+) induced fluorescence quenching is due to its binding to BSA rather than the fluorescence quenching by metal-metal interaction as in the case of Hg(2+). The Au-BSA showed excellent selectivity to Cu(2+) at various pH conditions. The 'turn off' of fluorescence can be retrieved by a Cu(2+) chelator glycine. Our results showed that gold clusters can be used as a 'turn off' sensor for copper and a 'turn on' sensor for glycine. Under the experimental conditions, the probe showed a response for Cu(2+) over a range of 100 μM to 5 mM with a detection limit of 50 μM. The role of Cu(2+) in the misfolding and disassembly of Prion Protein (PrP) leading to various maladies is well ascertained. The methodology we reported here seems to be useful in supplementing other techniques in predicting disease conditions involving Cu(2+).
本文报道了使用牛血清白蛋白（Au-BSA）合成的荧光金纳米簇用于检测活细胞中的铜离子。研究发现，纳米簇的荧光被 Cu(2+)猝灭，从而能够在细胞中进行检测。该纳米传感器的选择性在存在多种阳离子（不包括 Hg(2+)）的情况下得到了证明。我们没有研究 Hg(2+)的影响，因为之前已有报道。本研究表明，Cu(2+)诱导的荧光猝灭是由于其与 BSA 结合，而不是像 Hg(2+)那样通过金属-金属相互作用导致的荧光猝灭。Au-BSA 在各种 pH 条件下对 Cu(2+)表现出优异的选择性。通过 Cu(2+)螯合剂甘氨酸可以恢复荧光的“关闭”。我们的结果表明，金纳米簇可用作铜的“关闭”传感器和甘氨酸的“开启”传感器。在实验条件下，该探针对 Cu(2+)的响应范围为 100 μM 至 5 mM，检测限为 50 μM。Cu(2+)在朊病毒蛋白（PrP）的错误折叠和解体导致各种疾病中的作用已得到充分证实。我们在这里报道的方法似乎可用于补充其他技术，以预测涉及 Cu(2+)的疾病状况。
