Abstract：
Chitosan is an abundant natural polysaccharide that contains a lot of amino and hydroxyl groups. It possesses great potential for biomedical applications owing to its low toxicity, biodegradability and low cost. Herein, a novel chitosan-based fluorescent copolymer (WS-CS-TPA) was designed and synthesized via nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), water-soluble chitosan (WS-CS) and an aggregation-induced emission (AIE) fluorogen (AIEgen) triphenylamine derivative (TPA-NH2). Under ultrasonic treatment, 1.16 g TPA-NH2 and 1.1 g WS-CS can be conjugated by 0.7 g HCCP at room temperature. The obtained copolymer shows amphiphilic property and could assemble into nanoparticles with size about 100 nm. After self-assembly, TPA-NH2 was aggregated in the core, thus exhibiting superb AIE feature with intense green fluorescence emission in aqueous media. On the other hand, hydrophilic WS-CS was coated on the surface of nanoparticles and endowed their high water dispersibility. Results from preliminary biological assays suggested that WS-CS-TPA can be internalized by cells and exhibits low cytotoxicity, suggesting their great potential for biological imaging and intracellular drug delivery.
摘要：
壳聚糖是一种丰富的天然多糖，含有大量的氨基和羟基。由于其低毒性，在生物医学应用中具有巨大的潜力，生物可降解性和低成本。在这里，通过六氯环三磷腈（HCCP）的亲核取代，设计并合成了一种新型的壳聚糖基荧光共聚物（WS-CS-TPA），水溶性壳聚糖（WS-CS）和聚集诱导发射（AIE）荧光原（AIEgen）三苯胺衍生物（TPA-NH2）。在超声波处理下，1.16gTPA-NH2和1.1gWS-CS可以在室温下通过0.7gHCCP缀合。所得共聚物表现出两亲性，可组装成粒径约为100nm的纳米颗粒。自组装后,TPA-NH2聚集在核心，因此，在水性介质中表现出极好的AIE特征，具有强烈的绿色荧光发射。另一方面,亲水性WS-CS被包覆在纳米粒子表面，赋予其高的水分散性。初步的生物学实验结果表明，WS-CS-TPA可以被细胞内化并表现出低的细胞毒性，表明它们在生物成像和细胞内药物递送方面的巨大潜力。
