Direct and indirect immunolabelling of HeLa cells with quantum dots

With excellent optical properties, quantum dots (QDs) have been made as attractive molecular probes for labelling cells in biological research. In this study high-quality CdSe QDs prepared in a paraffin-oleic acid system were used as fluorescent labels in direct and indirect detection of carcinoembryonic antigen (CEA), a cancer marker expressed on the surface of HeLa cells. The primary antibody (Ab) (rabbit anti-CEA8) and secondary Ab (goat anti-rabbit IgG) were covalently linked to carboxyl-functioned CdSe QDs, and both the QDs-antibody and QDs-IgG probes were successfully used to label HeLa cells. The present study demonstrates the practicability of CdSe QDs as an attractive type of fluorescent labels for biological applications such as protein probes and cell imaging.