title: Synthesis of highly luminescent and biocompatible CdTe/CdS/ZnS quantum dots using microwave irradiation: a comparative study of different ligands.
abstract: We compared the effects of several ligands frequently used in aqueous synthesis, including L-cysteine, L-cysteine hydrochloride, N-acetyl-L-cysteine (NAC), glutathione and 3-mercaptopropionic acid, for microwave synthesis of CdTe quantum dots (QDs) in a sealed vessel with varied temperatures and times, and then developed a rapid microwave-assisted protocol for preparing highly luminescent, photostable and biocompatible CdTe/CdS/ZnS core-multishell QDs. The effects of molecular structures of these ligands on QD synthesis under high temperatures were explored. Among these ligands, NAC was found to be the optimal ligand in terms of the optical properties of resultant QDs and reaction conditions. The emission wavelength of NAC-capped CdTe QDs could reach 700 nm in 5 min by controlling the reaction temperature, and the resultant CdTe/CdS/ZnS core-multishell QDs could achieve the highest quantum yields up to 74% with robust photostability. In addition, the effects of temperature, growth time and shell-precursor ratio on shell growth were examined. Finally, cell culturing indicated the low cytotoxicity of CdTe/CdS/ZnS core-multishell QDs as compared to CdTe and CdTe/CdS QDs, suggesting their high potential for applications in biomedical imaging and diagnostics.
authors.affiliation: State Key Laboratory of Heavy Oil Processing and the Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, China.
authors.forename: Hua
authors.initials: H
authors.lastname: He
authors.forename: Xing
authors.initials: X
authors.lastname: Sun
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.forename: Hai
authors.initials: H
authors.lastname: Xu
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D019187:Cadmium Compounds / Q000737:chemistry* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D049449:Luminescence; D008872:Microwaves; D015394:Molecular Structure; D010316:Particle Size; D045663:Quantum Dots; D013329:Structure-Activity Relationship; D013440:Sulfides / Q000737:chemistry* / Q000494:pharmacology; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry* / Q000494:pharmacology; D013696:Temperature; D017967:Zinc Compounds / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D001672:Biocompatible Materials; D019187:Cadmium Compounds; D008024:Ligands; D013440:Sulfides; D017967:Zinc Compounds; C034939:cadmium sulfide; C031238:zinc sulfide; D013691:Tellurium; C028337:cadmium telluride
keywords: biocompatibility; ligands; microwave irradiation; quantum dots; shell