MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Zhejiang Research Institute of Chemical Industry, Hangzhou 310023, China.
Carbohydr Polym. 2020 Feb 15;230:115614. doi: 10.1016/j.carbpol.2019.115614. Epub 2019 Nov 13.
Fluorescent bioprobs are in urgent demand to monitor important biological events in biomedicine. However, the aggregation-caused quenching character, high toxicity, water-insolubility and easy leakage property of conventional small molecular dyes hinder the development in this area. In this work, an aggregation-induced emission (AIE) bioconjugate was synthesised by labeling tetraphenylethylene (TPE) to quaternized chitosan (QCS). The TPE-QCS bioconjugate emits strong fluorescence even in solid state, and is cationic and water-soluble over a wide range of pH values. The TPE-QCS aqueous solution stained HeLa cells by dose- and time-depent manner and imaged living cells with bright fluorescence. Futhermore, the cationic bioconjugate was readily internalized by cells through endocytosis, and further aggragated to large sizes and adhered to negatively charged organelle membranes inside cells achieving fluorescent cell imaging with fluorescence enhancement and leakage-free staining. The AIE-active TPE-QCS with cationic nature, good water-solubility over a wide pH range and unique cell imaging properties could trace HeLa cells for as long as 23 passages, that was obviously superior to existing commercial cellular tracer, so has promising application prospects as ultra long-term tracer in biomedical field.
荧光生物探针在监测生物医学中重要的生物学事件方面有着迫切的需求。然而，传统小分子染料的聚集猝灭特性、高毒性、不溶于水和容易泄漏的性质阻碍了这一领域的发展。在这项工作中，通过将四苯乙烯（TPE）标记到季铵化壳聚糖（QCS）上，合成了一种聚集诱导发射（AIE）生物缀合物。TPE-QCS 生物缀合物即使在固态下也能发出强荧光，并且在很宽的 pH 值范围内带正电荷且水溶性好。TPE-QCS 水溶液以剂量和时间依赖的方式染色 HeLa 细胞，并对活细胞进行明亮荧光成像。此外，阳离子生物缀合物通过内吞作用容易被细胞内化，并进一步聚集到较大的尺寸上，并粘附在细胞内带负电荷的细胞器膜上，实现荧光增强和无泄漏染色的荧光细胞成像。具有阳离子性质、在很宽的 pH 范围内具有良好水溶性和独特细胞成像特性的 AIE 活性 TPE-QCS 可以追踪 HeLa 细胞长达 23 代，明显优于现有的商业细胞示踪剂，因此作为超长期示踪剂在生物医学领域具有广阔的应用前景。
