# Dual-Channel NIR Fluorescence Imaging for Precise Delineation of Gastric Tumor Margins

## TL;DR

A new dual-channel near-infrared imaging method helps surgeons more accurately identify gastric tumor margins during surgery, potentially improving outcomes.

## Contribution

A dual-channel NIR imaging strategy using IR-780 and ESS65-Cl for precise tumor and normal tissue delineation in gastric cancer surgery.

## Key findings

- ESS65-Cl selectively labels normal gastric cells while IR-780 targets tumor cells in human cell lines.
- Dual-channel imaging in xenograft models enabled distinct visualization of tumors and surrounding tissues.
- Both agents showed high targetability and efficient clearance, supporting their use in real-time surgical guidance.

## Abstract

Fluorescence imaging is a promising intraoperative technique for gastric cancer surgery, enabling clear visualization of surgical margins and detection of occult lesions. However, the lack of near-infrared (NIR) fluorescent probes specifically targeting gastric tumors and normal tissues remains a limitation. To address this, we developed a dual-channel imaging strategy using IR-780 (800 nm) for tumor detection and ESS65-Cl (700 nm) for normal gastric tissue identification. We evaluated their specificity in human gastric epithelial (GES-1) and cancer (SGC-7901) cells, confirming selective uptake: ESS65-Cl in normal gastric cells and IR-780 in tumor cells. In subcutaneous and orthotopic xenograft models, dual-channel imaging allowed simultaneous visualization of tumors and surrounding tissues in distinct colors. Pharmacokinetic analysis revealed that ESS65-Cl achieved a stomach signal-to-background ratio of 3.3 by 48 h, while IR-780 exhibited a tumor-to-background ratio of 4.0, demonstrating high targetability. Moreover, biodistribution studies confirmed efficient clearance of both agents. When combined, these fluorophores enabled precise intraoperative differentiation between gastric tissues and tumors. This approach holds substantial potential for improving surgical accuracy in gastric cancer resection, particularly in defining proximal esophageal margins and gastrectomy boundaries. By enhancing real-time tissue discrimination, dual-channel NIR imaging may increase surgical success rates and improve patient outcomes.