FSD EX Fluor™ 750 NHS Ester is a next-generation, amine-reactive NIR fluorescent dye developed through BioActs’ advanced technology. It delivers superior optical properties and brightness compared with spectrally similar dyes, supporting a wide range of biochemical and biological analyses. FSD EX Fluor™ 750 exhibits excitation and emission maxima (Ex/Em = 752/774 nm) similar to Alexa 750, Cy7, IRDye 750, and DyLight 755. The dye can be efficiently excited by a 750 nm laser line or dye-pumped source, emitting within the NIR region that penetrates tissues with minimal scattering and absorption. It demonstrates excellent brightness, sensitivity, and photostability for reliable fluorescence imaging.

The NHS ester form reacts with amine-modified oligonucleotides or primary amines—such as the ε-amino group of lysine or terminal amines of nucleotides—to form stable amide linkages. This reaction allows efficient and stable conjugation even at low biomolecule concentrations. FSD EX Fluor™ 750 NHS Ester is optimized for in vivo NIR imaging and detection applications.

Special Properties (NIR Characteristics)

FSD EX Fluor™ 680, 750, and 800 dyes emit within the near-infrared region (NIR-I, 650–900 nm), known as the optical window of biological tissues. In this spectral range, absorption and scattering by biomolecules such as hemoglobin, water, and lipids are minimal, allowing deep tissue penetration and low background autofluorescence. These dyes provide high signal-to-noise ratios and excellent photostability, making them ideal for in vivo and deep-tissue fluorescence imaging.