title: Dissecting the Factors Affecting the Fluorescence Stability of Quantum Dots in Live Cells.
abstract: Labeling and imaging of live cells with quantum dots (QDs) has attracted great attention in the biomedical field over the past two decades. Maintenance of the fluorescence of QDs in a biological environment is crucial for performing long-term cell tracking to investigate the proliferation and functional evolution of cells. The cell-penetrating peptide transactivator of transcription (TAT) is a well-studied peptide to efficiently enhance the transmembrane delivery. Here, we used TAT peptide-conjugated QDs (TAT-QDs) as a model system to examine the fluorescence stability of QDs in live cells. By confocal microscopy, we found that TAT-QDs were internalized into cells by endocytosis, and transported into the cytoplasm via the mitochondria, Golgi apparatus, and lysosomes. More importantly, the fluorescence of TAT-QDs in live cells was decreased mainly by cell proliferation, and the low pH value in the lysosomes could also lower the fluorescence intensity of intracellular QDs. Quantitative analysis of the amount of QDs in the extracellular region and whole cells indicated that the exocytosis was not the primary cause of fluorescence decay of intracellular QDs. This work facilitates a better understanding of the fluorescence stability of QDs for cell imaging and long-term tracking in live cells. Also, it provides insights into the utility of TAT for transmembrane transportation, and the preparation and modification of QDs for cell imaging and tracking.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Wang
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Shu-Lin
authors.initials: SL
authors.lastname: Liu
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Yuan-Jun
authors.initials: YJ
authors.lastname: Hu
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Zhi-Quan
authors.initials: ZQ
authors.lastname: Tian
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Zhi-Ling
authors.initials: ZL
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Dai-Wen
authors.initials: DW
authors.lastname: Pang
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D058948:Cell Tracking; D057846:Cell-Penetrating Peptides / Q000737:chemistry / Q000494:pharmacology*; D004705:Endocytosis / Q000187:drug effects; D005453:Fluorescence; D008247:Lysosomes / Q000187:drug effects; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging; D045663:Quantum Dots / Q000008:administration & dosage / Q000737:chemistry*; D013194:Staining and Labeling
chemical_list: D057846:Cell-Penetrating Peptides
keywords: fluorescence stability; influence factors; live cells; quantum dots; transactivator of transcription