title: The application of CdSe quantum dots with multicolor emission as fluorescent probes for cell labeling.
abstract: Herein, highly luminescent CdSe quantum dots (QDs) with emissions from the blue to the red region of visible light were synthesized by using a simple method. The emission range of the CdSe QDs could be tuned from λ=503 to 606 nm by controlling the size of the CdSe QDs. Two amino acids, L-tryptophan (L-Trp) and L-arginine (L-Arg), were used as coating agents. The quantum yield (QY) of CdSe QDs (green color) with an optimized thickness could reach up to 52 %. The structures and compositions of QDs were examined by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Optical properties were studied by using UV/Vis and photoluminescence (PL) spectroscopy and a comparison was made between uncoated and coated CdSe QDs. The amino acid-modified β-cyclodextrin (CD)-coated CdSe QDs presented lower cytotoxicity to cells for 48 h. Furthermore, amino acid-modified β-CD-coated green CdSe QDs in HepG2 cells were assessed by using confocal laser scanning fluorescence microscopy. The results showed that amino acid-modified β-CD-coated green CdSe QDs could enter tumor cells efficiently and indicated that biomolecule-coated QDs could be used as a potential fluorescent probe.
authors.affiliation: Key Laboratory of Natural Medicine and Immune Engineering, Henan University, Kaifeng 475004 (China), Fax: (+86) 371-22864665. zhaomeixia2011@henu.edu.cn.
authors.forename: Mei-Xia
authors.initials: MX
authors.lastname: Zhao
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Er-Zao
authors.initials: EZ
authors.lastname: Zeng
authors.forename: Chao-Jie
authors.initials: CJ
authors.lastname: Wang
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry* / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005453:Fluorescence; D006801:Humans; D045663:Quantum Dots / Q000737:chemistry*; D018036:Selenium Compounds / Q000737:chemistry* / Q000633:toxicity; D013194:Staining and Labeling
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide
keywords: amino acids; fluorescent probes; labeling cells; multicolor; quantum dots