Bright Chromenylium Polymethine Dyes Enable Fast, Four-Color In Vivo Imaging with Shortwave Infrared Detection

• DOI: 10.1021/jacs.0c11599
• Publication Date: 2021-05-03T23:53:10Z
• Authors: Emily D. Cosco; Bernardo A. Arús; Anthony L. Spearman; Timothy L. Atallah; Irene Lim; Olivia S. Leland; Justin R. Caram; Thomas S. Bischof; Oliver T. Bruns; Ellen M. Sletten
• Keywords: Indocyanine Green

Optical imaging within the shortwave infrared (SWIR, 1000–2000 nm) region of electromagnetic spectrum has enabled high-resolution and high-contrast in mice, non-invasively. Polymethine dyes, with their narrow absorption spectra high coefficients, are optimal probes for fast multiplexed SWIR imaging. Here, we expand upon multiplexing capabilities by obtaining brighter polymethine dyes varied excitation wavelengths spaced throughout near-infrared (700–1000 region. Building on flavylium dye scaffold, explored derivatives functional group substitution at 2-position, deemed chromenylium dyes. The reported have reduced nonradiative rates enhanced emissive properties, enabling non-invasive mice a single color 300 fps three colors 100 fps. Combined containing red-shifted julolidine heterocycle indocyanine green, distinct channels well-separated provide video-rate vivo four colors.