NIR-II Fluorescence Endoscopy for Targeted Imaging of Colorectal Cancer.

Endoscopy is a clinical gold standard to exam the interior of a hollow organ or body cavity. For the first of time, this study presents the design and construction of a fluorescent endoscopic system that harnesses the power of the second near-infrared window II (NIR-II) fluorescence imaging. An NIR-II fluorescent molecular probe, indocyanine green (ICG) conjugated bevacizumab (Bev-ICG) that targets vascular endothelial growth factor (VEGF), is successfully synthesized and evaluated along with the NIR-II endoscopy imaging system. Simultaneous NIR-II fluorescence and white-light (WL) imaging of VEGF is validated in an orthotopic rat colorectal cancer model. This NIR-II endoscopy system is a generalizable design, and it is compatible with the most of current clinic endoscopies. Similar hardware upgrades are expected to greatly promote the application of NIR-II fluorescent imaging in the clinic.