Cyanine 5.5 (Cy5.5)-conjugated anti-guinea pig antibodies are near-infrared (NIR) fluorescent immunoreagents designed for the sensitive detection of guinea pig antigens in advanced fluorescence-based assays. With excitation maxima between approximately 675–683 nm and emission maxima of 694–703 nm, Cy5.5 operates within the NIR optical window, where tissue autofluorescence and light scattering are significantly reduced. These optical properties make Cy5.5 particularly valuable for multiplex fluorescence imaging, deep tissue visualization, and in vivo molecular imaging applications.

Fluorescence Properties

Cy5.5 exhibits a high molar extinction coefficient (~250,000 M^-1cm^-1) and a quantum yield of approximately 0.27, providing excellent signal intensity and photostability. Compared with Cy5, its longer emission wavelength offers improved photon penetration through biological tissues while minimizing background fluorescence, making it highly suitable for near-infrared imaging.

Applications and Advantages

• Broad application range: Suitable for flow cytometry, immunofluorescence, immunohistochemistry, immunocytochemistry, ELISA, and Western blotting.
• In vivo imaging: Near-infrared emission enables superior tissue penetration and reduced autofluorescence for whole-body and deep tissue fluorescence imaging.
• Multiplex fluorescence: Compatible with other NIR fluorophores such as Cy7, enabling simultaneous detection of multiple biological targets with minimal spectral overlap.
• Tandem dye options: PE/Cy5.5 conjugates are available for multicolor flow cytometry, providing efficient excitation at 488 nm with emission near 695 nm.