Water-soluble mercaptoundecanoic acid (MUA)-coated CdTe quantum dots: one-step microwave synthesis, characterization and cancer cell imaging.

In this study, a one-step approach for aqueous synthesis of highly luminescent semiconductors, CdTe quantum dots (QDs), using long-chain thiols-mercaptoundecanoic acid (MUA) as surface ligand, was developed in a microwave irradiation system. The synthetic conditions were systematically investigated. The as-prepared MUA-coated QDs were characterized by various spectroscopy techniques, transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). The experimental results document that MUA-coated CdTe QDs have small diameter, good stability, high luminescence and long lifetime. Particularly, it was confirmed, using fluorescence correlation spectroscopy (FCS) that, compared with other ligand, MUA formed a thicker ligand layer on the QD surfaces, which will help their stability and conjugation with biomolecules. Furthermore, MUA-coated QDs were successfully used for HeLa cell imaging.