超声响应性纳米粒子用于超声/光声成像引导下声动力/饥饿治疗小鼠结直肠癌

目的 制备载四苯基卟啉锌（TPZ）、葡萄糖氧化酶（GOD）与全氟戊烷的超声响应性纳米粒子（NP）TPZ-GOD NP，并评估其超声/光声双模态成像效果及介导声动力治疗（SDT）联合饥饿治疗小鼠结直肠癌的效果。方法 以薄膜水化法制备载TPZ及GOD的NP。观察TPZ-GOD NP基本特性，以紫外分光光度计检测其超声辐照下释放GOD量，以流式细胞仪检测结直肠癌CT-26细胞与TPZ-GOD NP共同孵育后细胞吞噬情况，于荧光显微镜下观察超声辐照后TPZ-GOD NP细胞毒性活性氧产生情况。检测TPZ-GOD NP增强体内外超声/光声双模态成像效果；观察TPZ-GOD NP介导SDT、饥饿治疗及二者联合对移植瘤小鼠模型的作用。结果 成功制备TPZ-GOD NP，颗粒呈球形，大小均一，平均粒径（262.10±62.92）nm。超声辐照后，GOD释放量随时间而增加。TPZ-GOD NP可被CT-26细胞吞噬，超声辐照后可产生大量细胞毒性活性氧；可发生液气相变，增强体内外超声造影效果。体外光声成像显示，TPZ-GOD NP光声信号值随浓度而呈线性增加。经尾静脉注射TPZ-GOD NP后，小鼠肿瘤区域内光声信号明显增强；SDT或饥饿治疗均可杀伤部分CT-26细胞，二者联合效果更佳。结论 制备TPZ-GOD NP具有超声响应性，可用于超声/光声双模态成像引导下声动力联合饥饿治疗小鼠结直肠癌。

Ultrasound responsive nanoparticles for ultrasound/photoacoustic imaging guided sonodynamic/starvation therapy of colorectal cancer in mice

Objective To prepare ultrasound responsive nanoparticles (NP) TPZ-GOD NP with zinc porphyrin (TPZ), glucose oxidase (GOD) and perfluoropentane, also to evaluate the effect of ultrasound/photoacoustic imaging and mediating sonodynamic therapy (SDT)/starvation therapy for colorectal cancer in mice. Methods Ultrasound responsive NP were synthesised by using a film hydration method with TPZ and GOD. The properties of TPZ-GOD NP were assessed, and the release amount of GOD assisted by ultrasound irradiation was evaluated. The intracellular uptake of CT-26 cells co-incubated with TPZ-GOD NP were studied with flow cytometry after various intervals of incubation. The cytotoxic reactive oxygen species generation of TPZ-GOD NP after ultrasound stimulation were observed under fluorescence microscope. Both in vitro and in vivo enhanced ultrasound/photoacoustic imaging performances were detected as well. The effects of SDT, starvation and the combined therapy for xenotransplant model mice were observed with ultrasound/photoacoustic imaging under the guidance of TPZ-GOD NP. Results TPZ-GOD NP were successfully fabricated, showing homogenized size distribution, the average particle size was (262.10±62.92)nm. Upon ultrasound irradiation, the release of GOD increased with time. TPZ-GOD NP could be phagocytized by CT-26 cells, and a large number of cytotoxic reactive oxygen species could be produced after ultrasonic irradiation. Liquid-gas phase transition occurred to enhance the effect of contrast-enhanced ultrasound in vivo and in vitro. In vitro photoacoustic imaging showed that the photoacoustic signals of TPZ-GOD NP increased linearly with the increase of concentration. After injection of TPZ-GOD NP into the tail vein of mice, the photoacoustic signals of tumor area remarkably enhanced. CT-26 cells were killed after the treatment of SDT or starvation therapy alone, while the killing effect of the combined therapy was better than of single ones. Conclusion The successfully prepared ultrasound responsive TPZ-GOD NP could be used for combined therapy (SDT/starvation therapy) for colorectal cancer in mice under the guidance of ultrasound/photoacoustic imaging.