摘要
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-Au NCs和D-NIBC-Au NCs）.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-Au NCs）和8.2%（D-NIBC-Au NCs）,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。
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-Au NCs） and N-isobutyryl-D-cysteine（D-NIBC-Au NCs）, respectively. Transmission electron microscopy（TEM images） of the L-NIBC-Au NCs and D-NIBC-Au NCs reveal that the particle sizes of both two Au NCs are around 1.9±0.7 nm. The UV-Vis absorption spectra of L-NIBC-Au NCs and D-NIBC-Au NCs are basically identical and both two Au NCs 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-Au NCs and D-NIBC-Au NCs 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-Au NCs and D-NIBC-Au NCs 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-Au NCs and D-NIBC-Au NCs 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-
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2016年第4期363-368,共6页
Acta Chimica Sinica
基金
国家杰出青年基金项目(No.51325302)
国家自然科学基金项目(Nos.51533007
51521001)资助~~
关键词
金纳米团簇
近红外
荧光探针
手性
gold nanoclusters
near-infrared
fluorescent probe
chirality
