Abstract:

Fluorophores in the shortwave infrared spectral region (greater than 800 nm) are currently widely used in the biomedical field. The ideal dye should be bright, highly photochemically stable, biocompatible and easy to derivatize to introduce functional groups. In this work, a NIR fluorescent dye EC5 with dual modifiable sites was developed through an efficient 5-step synthesis route using 7-bromo-2-naphthol as a raw material. The resulted compound was characterized by nuclear magnetic resonance (NMR) hydrogen spectroscopy, carbon spectroscopy, high-resolution mass spectrometry (HRMS) and X-ray diffraction (XRD). The maximum absorption and emission wavelengths of EC5 were 871nm and 923nm, respectively, with a high fluorescence brightness of 38,715 and a fluorescence lifetime of 0.70 ns in dichloromethane. EC5 was also exhibited an excellent anti-aggregate ability with the concentration up to 100 μM and a high photostability with a high-density power of 808 nm laser beam. Finally, EC5 was used for high temporal and spatial resolution fluorescence imaging of BALB/c mice as well as anti-counterfeiting writing, which demonstrated that EC5 has a wide range of application prospects in the field of near-infrared fluorescence in vivo imaging.

Key words: near-infrared, molecular synthesis, organic compounds, dyes, imaging

摘要：

短波红外光谱区（大于800nm）的荧光团目前广泛用于生物医学领域，理想的染料应明亮、光化学稳定性高、生物相容性好并且易于衍生以便引入功能性基团。本研究开发了一种具有双可修饰位点的二苯并呫吨类近红外荧光染料EC5可用于荧光成像。以7-溴-2-萘酚为起始原料，通过高效的5步级联反应得到EC5，并由核磁共振氢谱、碳谱、高分辨质谱及X-射线衍射鉴定。EC5在二氯甲烷中最大吸收和发射波长分别为871nm和923nm，荧光亮度高达38715，荧光寿命为0.70ns。同时测试了EC5在极性溶剂中的聚集性、光化学稳定性，结果表明：EC5即使高达100μM 也不会出现聚集现象，高功率880nm激光持续照射仍能保持吸光度几乎不变，同时高浓度生物活性物质亦不会使EC5染料降解，说明其具有优异的抗聚集性、抗光漂白能力及化学稳定性。最后使用EC5对BALB/c小鼠进行了高时空分辨的荧光成像以及防伪书写，说明EC5在近红外荧光活体成像领域具有广泛的应用前景。

关键词: 近红外, 分子合成, 有机化合物, 染料, 成像