Synthesis of Water-Soluble Cyanine Dyes for Labeling Applications

Maddelyn Hoehn, Lauren Endres

Biology, College of Arts and Sciences, SUNY Polytechnic Institute, Utica, NY, USA

Near-infrared fluorescent contrasts have changed the way biomedical and clinical research is conducted by improving the ways cells are imaged due to their ability to produce high-resolution images. A straightforward synthesis and easy purification of these contrasts while also maintaining their strong optical properties for imaging is highly desirable. The goal of this study was to develop a simple yet efficient method for synthesizing cyanine dyes that are applicable in medical and biological science for high-resolution, near-infrared fluorescence (NIRF) imaging. The end-group and linker were synthesized for CyAL5, CyAL5.5, CyAM7, and CyAM7.5 where they were then each combined respectively to make the cyanine dyes. High-performance liquid chromatography was used to obtain each compound and mass spectroscopy was used to verify the presence of CyAL5, CyAL5.5, CyAM7, and CyAM7.5 respectively. The synthesized cyanine dyes are water-soluble and display strong fluorescence emissions. Their straightforward synthesis and purification process in addition to their exceptional optical properties make them highly desirable for biomedical research and in vivo imaging applications.