作者：

Boping Jing1†, Ruijie Qian1†, Dawei Jiang1, Yongkang Gai1, Zhen Liu1, Feng Guo2, Sen Ren3, Yu Gao1, Xiaoli Lan1* and Rui An

引用瑞禧生物产品：

DSPE-PEG, DSPE-PEG2000-Cy5, DSPE-PEG2000-N3

作者：
Boping Jing1†, Ruijie Qian1†, Dawei Jiang1, Yongkang Gai1, Zhen Liu1, Feng Guo2, Sen Ren3, Yu Gao1, Xiaoli Lan1* and Rui An
引用瑞禧生物产品：
DSPE-PEG, DSPE-PEG2000-Cy5, DSPE-PEG2000-N3

摘要：
摘要背景：结肠癌因肿瘤手术中切除不彻底而导致高死亡率。多模态成像技术可为术前评估及术中影像引导提供支持。作为生物相容性纳米载体，细胞外囊泡在多模态成像领域展现出巨大潜力。本研究旨在合成一种基于细胞外囊泡的纳米探针，用于通过正电子发射断层扫描/计算机断层扫描（PET/CT）及近红外荧光（NIRF）成像技术可视化结肠癌，并探讨其在动物模型结肠癌影像引导手术中的应用价值。
结果：成功从脂肪源性干细胞（ADSCs）中分离出细胞外囊泡，并通过透射电子显微镜（TEM）观察到其膜囊泡结构。动态光散射（DLS）检测显示，细胞外囊泡的流体力学直径约为140 nm，Zeta电位为−7.93±0.24 mV。共聚焦显微镜观察表明，细胞外囊泡对肿瘤细胞具有强结合能力。采用基于点击化学的预靶向策略，实现了体内PET成像。PET图像及生物分布结果表明，良好预靶向时间为20小时，而注射⁶⁸Ga-L- NETA - DBCO 后，良好成像时间为2小时。 NIRF 图像显示，注射纳米颗粒后各时间点肿瘤均呈现清晰影像，且肿瘤/肌肉比值在注射后20小时达到峰值。我们的数据还表明，PET/CT 和 NIRF 成像均能清晰显示原位结肠癌模型，为术前评估提供了依据。在实时 NIRF 成像下，肿瘤的位置及边界均可清晰观察。
结论：简言之，这种新型纳米探针或可用于结肠癌的多模态成像及 NIRF 图像引导手术。更重要的是，本研究为细胞外囊泡作为纳米载体的临床应用提供了新的可能性。
关键词：细胞外囊泡、PET/CT、 NIRF 、多模态成像、图像引导手术

图 1 ADSCs-EV 的鉴定与特性。

Abstract 
Backgroud: Colon cancer contributes to high mortality rates as the result of incomplete resection in tumor surgery. Multimodal imaging can provide preoperative evaluation and intraoperative image-guiding. As biocompatible nanocarriers, extracellular vesicles hold great promise for multimodal imaging. In this study, we aim to synthesized an extracellular vesicles-based nanoprobe to visualize colon cancer with positron-emission tomography/computed tomography (PET/CT) and near-infrared fluorescence (NIRF) imaging, and investigated its utility in image-guided surgery of colon cancer in animal models. 
Results: Extracellular vesicles were successfully isolated from adipose-derived stem cells (ADSCs), and their membrane vesicles were observed under TEM. DLS detected that the hydrodynamic diameters of the extracellular vesicles were approximately 140 nm and the zeta potential was−7.93±0.24 mV. Confocal microscopy showed that extracellular vesicles had a strong binding ability to tumor cells. A click chemistry-based pre-targeting strategy was used to achieve PET imaging in vivo. PET images and the biodistribution results showed that the best pre-targeting time was 20 h, and the best imaging time was 2 h after the injection of 68 Ga-L-NETA-DBCO. The NIRF images showed that the tumor had clear images at all time points after administration of nanoparticles and the Tumor/Muscle ratio peaked at 20 h after injection. Our data also showed that both PET/CT and NIRF imaging clearly visualized the orthotopic colon cancer models, providing preoperative evaluation. Under real-time NIRF imaging, the tumor location and tumor boundary could be clearly observed. 
Conclusions: In brief, this novel nanoprobe may be useful for multi-modal imaging of colon cancer and NIRF imageguided surgery. More importantly, this study provides a new possibility for clinical application of extracellular vesicles as nanocarriers. 
Keywords: Extracellular vesicles, PET/CT, NIRF, Multimodal imaging, Image-guided surgery