Mercaptoacetic acid (MA) capped CdTe, CdTe/CdS, CdTe/ZnS quantum dots (QD) and glutathione (GSH)-capped CdTe QDs were directly synthesized in aqueous media. The fabricated CdTe-GSH QDs have an ultra small hydrodynamic diameter (3～4 nm) and possess high quantum yields (47.3%). In vitro hemolysis testing showed that the hemolysis rates (HR) of CdTe/ZnS-MA and CdTe-GSH were less than 5% (concentration being 0.05 mmol/L), which were lower than CdTe-MA and CdTe/CdS-MA QDs, meeting the requirements for biomedical materials. The toxicity of QD in vivo was tested by injected QD in mice through tail vein. Fluorescence microscopy showed that a high dosage (0.4 mmol/10 g) of CdTe-GSH and CdTe/ZnS-MA QD was distributed mainly in the heart, liver, spleen and kidney tissues and caused varying degrees of tissue lesions.

Key words: red quantum dot, hemolysis, toxicity, glutathione