CdSe nano-particles coated with thiol-terminated oligo(ethylene oxide)for protein targeting reagent
Y. Ito, H. Tsutsumi
Yamaguchi University, JP
Keywords: CdSe, oligo(ethylene oxide), antibody conjugated
Abstract:Fluorescent labeling reagents are used as medical and biochemical research reagents that label specific protein, antigen, antibody, and DNA. However, the chromophoric groups (organic compounds) usually are not stable under long-time ultra violet (UV) excitation. Nanometer-sized semiconductor particles (for example, CdS or CdSe nanometer-sized particles) provide high intensity fluorescence with durability under long-time UV irradiation. CdSe nano-particles are usually stabilized by surface modification with hydrophobic reagents. Solubilization of the CdSe particles into water is one of the key processes of application CdSe nano-particles to fluorescent labeling reagents under aqueous condition. We prepared the CdSe nano-particles coated with thiol-terminated oligo(ethylene oxide), TPEG. The coated CdSe nano-particles are water-soluble and the solubilizing efficiency into water is 77 % estimated from UV-visible spectra. Coupling of the CdSe nano-particles coated with thiol-terminated oligo(ethylene oxide) and monoclonal antibody (anti-tubulin antibody was used.) was performed by using water-soluble carbodiimide. The fluorescence microscopic observation of the stained HeLa cells by the antibody conjugated CdSe nano-particles was performed. Clearly stained tubulin is observed in the cells.