### 手性金纳米团簇:一种新型近红外荧光探针

1. a. 武汉理工大学 材料复合新技术国家重点实验室 湖北武汉 430070;
b. 武汉理工大学 化学化工与生命科学学院 湖北武汉 430070
• 投稿日期:2016-01-19 发布日期:2016-04-08
• 通讯作者: 张明曦, 孙涛垒 E-mail:mxzhang@whut.edu.cn;suntl@whut.edu.cn
• 基金资助:

项目受国家杰出青年基金项目(No. 51325302)和国家自然科学基金项目(Nos. 51533007, 51521001)资助.

### Chiral Gold Nanoclusters: A New Near-Infrared Fluorescent Probe

Gao Guanbina, Gong Dejunb, Zhang Mingxia, Sun Taoleia,b

1. a State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China;
b School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China
• Received:2016-01-19 Published:2016-04-08
• Supported by:

Project supported by China National Funds for Distinguished Young Scientists (Grant No. 51325302) and the National Natural Science Foundation of China (Grant Nos. 51533007, 51521001).

Near-infrared (NIR) fluorescence facilitates noninvasive bio-imaging because it involves less interference from blood and tissue auto-fluorescence and high transparency. Nowadays, the research of new NIR fluorescent probes with favorable biocompatibility, high quantum yield, high stability and long-wavelength emission band has become the focus of bio-nanotechnology. Herein, we introduced NIBC enantiomers onto the surface of gold nanoclusters and synthesized chiral gold nanoclusters anchored with N-isobutyryl-L-cysteine (L-NIBC-AuNCs) and N-isobutyryl-D-cysteine (D-NIBC-AuNCs), respectively. Transmission electron microscopy (TEM images) of the L-NIBC-AuNCs and D-NIBC-AuNCs reveal that the particle sizes of both two AuNCs are around 1.9±0.7 nm. The UV-Vis absorption spectra of L-NIBC-AuNCs and D-NIBC-AuNCs are basically identical and both two AuNCs have characteristic absorption peaks at 580 nm and 680 nm. Compared with the FT-IR spectra of NIBC, the vanishing of the S—H stretching vibration at the 2500~2600 cm-1 in the FT-IR spectra of L-NIBC-AuNCs and D-NIBC-AuNCs indicate that L-NIBC and D-NIBC have successfully anchored on to the surface of Au core by Au—S bond. The circular dichroism (CD) spectra of L-NIBC-AuNCs and D-NIBC-AuNCs show nearly a mirror image relationship at 230~360 nm, which means the chirality signal transmitted from molecular level to nanoscale level. Most important of all, both two water-soluble nanoclusters have fluorescence emission bands between 900~1000 nm which belong to the near infrared bands. And the fluorescence quantum yields of L-NIBC-AuNCs and D-NIBC-AuNCs are 6.9% and 8.2%, respectively. Cell toxicity experiments show that both two kinds of gold nanoclusters have no cytotoxicity even at the high concentration of 100 mg/L. Moreover, these gold nanoclusters also have unique chiroptical activity and potential chiral recognition ability. Based on the experiment mentioned above, these kinds of chiral gold nanoclusters can be used as a new kind of near-infrared fluorescent probe, which may have promising application in the near-infrared fluorescent imaging. These findings provide an interesting insight in the near-infrared fluorescence (NIRF) imaging techniques.