Abstract
BackgroudColon 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.ResultsExtracellular 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.ConclusionsIn brief, this novel nanoprobe may be useful for multi-modal imaging of colon cancer and NIRF image-guided surgery. More importantly, this study provides a new possibility for clinical application of extracellular vesicles as nanocarriers.Graphic
Highlights
At present, surgery still plays a crucial role in colon cancer treatment, with more than 50% of cancer patients undergoing surgery
Extracellular vesicles were successfully isolated from adipose-derived stem cells (ADSCs), and their membrane vesicles were observed under Transmission electron microscopy (TEM)
The near-infrared fluorescence (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
Summary
Surgery still plays a crucial role in colon cancer treatment, with more than 50% of cancer patients undergoing surgery. Multi-modal imaging has been performed to visualize cancer before. Jing et al J Nanobiotechnol (2021) 19:151 and during surgical procedures to provide pre- or intraoperative disease-specific images in real time [2]. Positron emission tomography/computed tomography (PET/CT) imaging can enable visualization of tumors and their regression or progression, offering high sensitivity, excellent penetration, and high spatial resolution [4]. Near-infrared fluorescence (NIRF, 650–1000 nm) imaging can provide anatomical information and real-time delineation of tumor because of the advantages of high temporal resolution, spatial resolution, super sensitivity and lower background [5,6,7]. Multi-modal PET/CT and NIRF imaging of colon cancer can be applied to obtain preoperative and intraoperative imaging of tumor
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