Novel molecular recognition via fluorescent resonance energy transfer using a biotin-PEG/polyamine stabilized CdS quantum dot.
A novel functionally PEGylated quantum dot (QD) was prepared by a coprecipitation method in the presence of the biotin-PEG/polyamine block copolymer. When CdCl2 and Na2S were mixed in aqueous media in the presence of the biotin-PEG-b-poly(2-(N,N-dimethylamino)ethyl methacrylate) [biotin-PEG/PAMA], a CdS QD with a size of ca. 5 nm was prepared. The polyamine segment was anchored on the surface of the formed CdS nanoparticle, whereas the PEG segment was tethered on the surface to form a hydrophilic palisade, thus improving the dispersion stability in aqueous media even under a high salt concentration condition. An effective fluorescent resonance energy transfer (FRET) was observed by the specific interaction of the biotin-PEG/PAMA stabilized CdS QD with TexasRed-labeled streptavidin of the physiological ionic strength of 0.15 M. The extent of the energy transfer was in proportion to the concentration of the TexasRed-streptavidin. This FRET system using the PEGylated CdS QD coupled with fluorescent-labeled protein can be utilized as a highly sensitive bioanalytical system.
Nagasaki
Yukio
Y
Department of Materials Science, Tokyo University of Science, Noda 278-8510, Japan. nagasaki@rs.noda.tus.ac.jp
Ishii
Takehiko
T
Sunaga
Yuka
Y
Watanabe
Yousuke
Y
Otsuka
Hidenori
H
Kataoka
Kazunori
K
D001710:Biotin / Q000737:chemistry*; D019187:Cadmium Compounds / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D011073:Polyamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties
D019187:Cadmium Compounds; D011073:Polyamines; D013440:Sulfides; C034939:cadmium sulfide; D011092:Polyethylene Glycols; D001710:Biotin