L‐Cysteine capped CdTe–CdS core–shell quantum dots: preparation,characterization and immuno‐labeling of HeLa cells

Functionalized CdTe–CdS core–shell quantum dots (QDs) were synthesized in aqueous solution via water‐bathing combined hydrothermal method using L‐cysteine (L‐Cys) as a stabilizer. This method possesses both the advantages of water‐bathing and hydrothermal methods for preparing high‐quality QDs with markedly reduced synthesis time, and better stability than a lone hydrothermal method. The QDs were characterized by transmission electronic microscopy and powder X‐ray diffraction and X‐ray photoelectron spectroscopy. The CdTe–CdS QDs with core–shell structure showed both enhanced fluorescence and better photo stability than nude CdTe QDs. After conjugating with antibody rabbit anti‐CEACAM8 (CD67), the as‐prepared l ‐Cys capped CdTe–CdS QDs were successfully used as fluorescent probes for the direct immuno‐labeling and imaging of HeLa cells. It was indicated that this kind of QD would have application potential in bio‐labeling and cell imaging. Copyright © 2009 John Wiley & Sons, Ltd.