Journal: Accounts of Chemical Research

Article Title: Chromenylium and Flavylium Polymethine Fluorophores Light Up the Shortwave Infrared Region

doi: 10.1021/acs.accounts.5c00892

Figure Lengend Snippet: Progress of SWIR fluorescence imaging. (A) Clinical imaging setups often use surgical robots to toggle between visible and NIR light visualization channels with fixed parameters. (B) Custom-built preclinical imaging setups operate in the NIR or SWIR regions with multiple colors and tunable parameters. Optical filters further define collection windows to optimize signal-to-background ratios and/or modulate depth, contrast, and resolution. The subregions of the SWIR are particularly distinct due to the absorption of water, rendering optical filter considerations a more critical component of SWIR imaging setups. (C) Electromagnetic spectrum and associated imaging-related properties. (D, E) Cyanine dye example (D) or Chrom, Flav dye derivatives (E), with relative absorption wavelengths and clinical progress. (F) SWIR imaging examples in mice with ICG (i), Flav7 (ii), Chrom7 (iii), or Chrom9 (iv).

Article Snippet: These Chrom dyes are blue-shifted from their Flav congeners, but on average result in a 2.8-fold increase in Φ F . Taking the dimethylamino-containing heptamethine variant as an example, Chrom7 is blue-shifted by ∼50 nm (λ max,abs = 975 nm) compared to Flav7 , yet Chrom7 is significantly brighter, owing to its impressive Φ F (1.70% in DCM).

Techniques: Fluorescence, Imaging, In Vivo Imaging