700-nm Zwitterionic Near-Infrared Fluorophores for Dual-Channel Image-Guided Surgery.

Abstract

The purpose of this study was to develop a family of 700-nm zwitterionic pentamethine indocyanine near-infrared fluorophores that would permit dual-channel image-guided surgery. Three complementary synthetic schemes were used to produce novel zwitterionic chemical structures. Physicochemical, optical, biodistribution, and clearance properties were compared to Cy5.5, a conventional pentamethine indocyanine now used for biomedical imaging. ZW700-1a, ZW700-1b, and ZW700-1c were synthesized, purified, and analyzed extensively in vitro and in vivo. All molecules had extinction coefficients ≥199,000 M(-1) cm(-1), emission ≥660 nm, and stability ≥99 % after 24 h in warm serum. In mice, rats, and pigs, ≥80 % of the injected dose was completely eliminated from the body via renal clearance within 4 h. Either alone or conjugated to a tumor targeting ligand, ZW700-1a permitted dual-channel, high SBR, and simultaneous imaging with 800-nm NIR fluorophores using the FLARE® imaging system. Novel 700-nm zwitterionic NIR fluorophores enable dual-NIR image-guided surgery.