Synthesis of silicon-substituted hemicyanines for multimodal SWIR imaging

SWIR dyes offer many advantages over their more common NIR congeners; however, the available options are limited. New SWIR imaging agents can be accessed by remodeling existing NIR molecules (i.e., hemicyanines (HD)). In this study, we syn-thesized SWIR-HD, a modified HD featuring silicon-dimethyl and benzo[cd]indolium groups that are designed to red-shift the absorbance and emission to 988 and 1126 nm, respectively. SWIR-HD was tested in three cell lines and shown to exhibit ex-cellent biocompatibility.