中文摘要：

目的构建一种新型天然高分子聚合物纳米超声造影微粒，表征其理化特征、体外显像效果及其对肿瘤细胞的结合能力和毒性。方法采用超声乳化法制备包裹液态氟碳PFOB的壳聚糖（CTS）纳米粒和FITC标记的壳聚糖纳米粒（FITc-cTs），表征其表面形态、粒径、Zeta电位和稳定性；评价纳米粒的体外超声显像效果，以激光共聚焦观察FITC—CTS与细胞的结合作用，流式细胞仪检测FITC—CTS对细胞的黏附比例。结果制备的纳米粒形态圆整，CTS纳米粒平均粒径为（248．52±7．96）nm，Zeta电位为（29．91±0．64）mV，FITC-CTS纳米粒平均粒径为（244．83±2．72）nm，Zeta电位为±（22．21±0．53）mV。纳米粒性质稳定，在体外能增强超声显影，激光共聚焦观察到纳米粒聚集在细胞膜周围，流式细胞仪测得纳米粒对细胞的黏附比例为（45．15±8．35）％。结论构建的CTS纳米粒性质稳定，体外能与肿瘤细胞MCF-7紧密结合，增强超声回声。

英文摘要：

Objective To develop a novel nanoparticle made of natural polymer as ultrasound contrast agent, and to char- acterize its physical and chemical characteristics and imaging effect in vitro, as well as to detect its combining ability and toxicity to cancer cells. Methods Chitosan （CTS） nanoparticle and chitosan nanoparticle marked with fluorescein isothio eyanate- CTS （FITC-CTS） were prepared using ultrasonic emulsification by packaging PFOB in the side. The surface mor- phology, particle diameter, Zeta potential and stability were characterized. Ultrasound imaging of the nanoparticle was e- valuated in vitro, its combining ability and adhesion ratio with cancer cells were respectively detected by confocal micro- scope and flow cytornetry. Results The nanoparticle was round in shape, the mean diameter and Zeta potential of CTS and F1TCCTSnanopartielewas （248.52±7.96）nm, ±（29.91±0.64）mV and （244.83±2.72）nm, （22.21±0.53）mV, respectively. It was stable and could enhance ultrasonic imaging in vitro, gathering around the cell membrane, and the ad- hesion ratio was （45.15±8.35）% by flow cytometry. Conclusion The novel chitosan nanoparticle is stable, which can closely bond to cancer cell MCF7 and enhance ultrasonic echo in vitro.