Biocompatible, near-infrared luminescent gold nanoclusters were synthesized in situ using as-prepared chitosan grafted with N-acetyl-l-cysteine (NAC-CS). The fluorescent gold nanoclusters coated with chitosan-N-acetyl-l-cysteine ([email protected]) were aggregated by multiple ultrasmall gold nanoclusters closing with each other, with strong fluorescence emission at 680 nm upon excitation at 360 nm. [email protected] did not display any appreciable cytotoxicity on cells even at a concentration of 1.0 mg mL^–1. [email protected] were more insensitive to H₂O₂ and trypsin compared with fluorescent gold nanoclusters coated with Albumin Bovine V ([email protected]), which make them have long time imaging in HeLa cells. Furthermore, the obvious fluorescence signal of [email protected]-CS appeared in the liver and kidney of the normal mice after 6 h injection. And the fluorescence intensity decreased after that because of the highly efficient clearance characteristics of ultrasmall nanoparticles. These findings demonstrated that [email protected] possessed good fluorescence, low cytotoxicity, and low sensitivity to some content of cells, allowing imaging of the living cells.

中文翻译：

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壳聚糖稳定的自组装荧光金纳米簇用于体内细胞成像和生物分布

使用已制备的接枝N-乙酰基-1-半胱氨酸（NAC-CS）的壳聚糖原位合成了生物相容的近红外发光金纳米簇。包覆有壳聚糖-N-乙酰基-1-半胱氨酸的荧光金纳米团簇（[电子邮件保护]）由多个彼此靠近的超小金纳米团簇聚集在一起，在360 nm激发时在680 nm处发出强烈的荧光。[受电子邮件保护]即使在1.0 mg mL ^–1的浓度下也没有对细胞显示任何明显的细胞毒性。[电子邮件保护]对H ₂ O ₂更加不敏感与胰蛋白酶相比，涂有白蛋白牛V（受电子邮件保护）的荧光金纳米簇使它们在HeLa细胞中具有长时间成像。此外，注射6小时后，正常小鼠的肝脏和肾脏中出现了[电子邮件保护的] -CS明显的荧光信号。之后，由于超小纳米粒子的高效清除特性，荧光强度降低。这些发现表明，[电子邮件保护的]具有良好的荧光性，低细胞毒性和对某些细胞含量的低敏感性，从而可以对活细胞成像。