Aqueous synthesis of highly luminescent surface Mn2+-doped CdTe quantum dots as a potential multimodal agent.

Mn(2+)-doped CdTe quantum dots (QDs) were synthesized directly via a facile surface doping strategy in aqueous solution. The best optical property emerged when the added amount of Mn(2+) was 5% compared to Cd(2+) in the CdTe nanoparticles and the reaction temperature was 60 °C. The fluorescence and magnetic properties of the QDs were studied. The as-prepared Mn(2+)-doped CdTe QDs have high quantum yield (48.13%) and a narrow distribution with an average diameter of 3.7 nm. The utility of biological imaging was also studied. Depending on the high quantum yield, cells in culture were illuminated and made more distinct from each other compared to results obtained with normal QDs. They also have a prominent longitudinal relaxivity value (r1= 4.2 mM(-1) s(-1)), which could indicate that the Mn(2+)-doped CdTe QDs can be used as a potential multimodal agent for fluorescence and magnetic resonance imaging.