iFluor(R) 690 maleimide

iFluor(R) 690 maleimide is a thiol-reactive, near-infrared fluorescent labeling dye developed for efficient and site-specific conjugation of biomolecules containing free sulfhydryl (-SH) groups, such as cysteine residues in proteins, peptides, and antibodies. With an excitation maximum around 685 nm and an emission maximum near 704 nm, iFluor(R) 690 provides strong near-infrared fluorescence with minimal background interference, making it particularly well-suited for applications requiring deep tissue penetration and reduced autofluorescence. The dye incorporates a maleimide functional group that reacts selectively and rapidly with thiol groups under mild physiological conditions, producing stable thioether linkages. Compared to conventional dyes such as Cy5 or Alexa Fluor(R) 680, iFluor(R) 690 maleimide demonstrates superior brightness, improved photostability, and enhanced water solubility, ensuring reliable performance in both in vitro and in vivo imaging. These properties make it an ideal reagent for antibody labeling, fluorescence microscopy, flow cytometry, immunoassays, multiplex detection, and in vivo imaging studies.