Luminogens with aggregation-induced emission (AIEgens) characteristics have been well developed and applied in various areas such as bio-imaging, theranostics, organic photoelectronics and chemo/bio sensors. However, most of the reported AIEgens suffer from the disadvantages of complex organic synthesis and high cost, as well as being environmentally unfriendly and hard to degrade, which have largely limited their real applications. In this work, we discovered berberine chloride, a natural isoquinoline alkaloid isolated from Chinese herbal plants, as an unconventional rotor-free AIEgen with bright solid-state emission and water-soluble characteristics. Single crystal structure analysis and optical property, viscosity, and host–guest interaction studies suggested that intramolecular vibration and twisted intramolecular charge transfer were responsible for the AIE phenomenon of berberine chloride. Moreover, berberine chloride was biocompatible and could specifically target lipid droplets in a fluorescence turn-on and wash-free manner, demonstrating the great potential of natural products as promising AIE probes.

中文翻译：

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从自然资源中探索生物相容性 AIEgens†

具有聚集诱导发射（AIEgens）特性的发光剂已得到很好的开发并应用于生物成像、治疗诊断、有机光电子学和化学/生物传感器等各个领域。然而，大多数已报道的AIEgens都存在有机合成复杂、成本高、环境不友好、难以降解等缺点，这在很大程度上限制了它们的实际应用。在这项工作中，我们发现了氯化小檗碱（一种从中草药中分离出来的天然异喹啉生物碱），它是一种非常规的无转子 AIEgen，具有明亮的固态发射和水溶性特性。单晶结构分析以及光学性质、粘度和主客体相互作用研究表明，分子内振动和扭曲的分子内电荷转移是氯化小檗碱的 AIE 现象的原因。此外，氯化小檗碱具有生物相容性，可以以荧光开启和免洗的方式特异性靶向脂滴，这证明了天然产物作为有前景的 AIE 探针的巨大潜力。