Aqueous Synthesis and Fluorescence-Imaging Application of CdTe/ZnSe Core/Shell Quantum Dots with High Stability and Low Cytotoxicity

CdTe/ZnSe core/shell quantum dots were directly synthesized in an aqueous condition by heating a mixed solution of ZnCl₂, NaHSe and CdTe QDs in the presence of mercaptosuccinic acid as a stabilizer. By controlling the size and composition, the CdTe/ZnSe QDs with emission wavelength ranging from 540 to 630 nm, high quantum yield (44%) and narrow full width at half maximum (FWHM) could be obtained. Characterization results with HRTEM, XRD and EDX have shown that the synthesized CdTe/ZnSe QDs have good monodispersity and a nice crystal structure, and exhibited better stability and less cytotoxicity as compared with CdTe QDs. Furthermore, luminescent QD-IgG bioprobes were produced to detect the breast cancer marker Her2 on the surface of fixed MCF-7 cancer cells for their optical imaging.