化学学报 ›› 2016, Vol. 74 ›› Issue (4): 363-368.DOI: 10.6023/A16010038 上一篇    下一篇

研究论文

手性金纳米团簇:一种新型近红外荧光探针

高冠斌a, 龚德君b, 张明曦a, 孙涛垒a,b   

  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
  • 收稿日期:2016-01-19 出版日期:2016-04-15 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 Online:2016-04-15 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).

近红外荧光成像具有低背景荧光干扰、强组织穿透力和对生物机体无光损伤等优点, 因此发展具有良好生物相容性、量子产率高、化学及光稳定性好的水溶性长波段近红外荧光探针成为目前的研究热点. 与有机近红外荧光染料相比, 无机纳米近红外荧光探针因其具有较高的摩尔消光吸光系数和荧光量子产率、抗光漂白能力强、发射光谱集中且可调等特点而备受重视. 采用N-异丁酰基-L(D)-半胱氨酸(N-isobutyryl-L(D)-cysteine, L(D)-NIBC)手性对映异构体作为还原剂和稳定剂一步法直接制备得到两种平均粒径小于2 nm的水溶性手性金纳米团簇(L-NIBC-AuNCs和D-NIBC-AuNCs). CD光谱显示二者在230~360 nm波段的圆二色性完美对称, 荧光光谱显示二者均在900~1000 nm的近红外波段具有较强的荧光发射峰, 且二者的荧光量子产率分别达到6.9% (L-NIBC-AuNCs)和8.2% (D-NIBC-AuNCs), 细胞毒性实验表明这两种手性金纳米团簇均无细胞毒性. 上述结果表明两种手性金纳米团簇不仅符合成为近红外荧光探针的基本要求, 而且还具有不对称光学活性和潜在的手性识别能力等独特性质. 手性金纳米团簇具有成为一类全新的近红外荧光探针的潜力, 为将来实现对特定分子通过手性识别来进行体内近红外荧光示踪和成像提供了全新的思路.

关键词: 金纳米团簇, 近红外, 荧光探针, 手性

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.

Key words: gold nanoclusters, near-infrared, fluorescent probe, chirality