<https://axispharm.com/product/cyanine3-carboxylic-acid/#product>
<http://schema.org/description>
"Free Cyanine3 carboxylic acid (Cy3® carboxylic acid analog), non-activated dye. Non-sulfonated reagent, with good solubility in organic solvents, and limited aquous solubility. The dye can be used as a non-reactive fluorophore, for control experiments, and for calibration.\r\n\r\nFor coupling with amines, and labeling, consider using Cyanine3 NHS ester, or water-soluble sulfo-Cyanine3 NHS ester."
<https://axispharm.com/product/cyanine3-carboxylic-acid/>