title: Oxygen-sensitive quantum dots for possible nanoscale oxygen imaging in cultured cells.
abstract: Quantum dots (QDs) are the semiconductor crystal with a nanometer particle size that emit fluorescence of a size-dependent wavelength. In this study, we examined whether L-cysteine-capped CdTe quantum dots (QD580, diameter ~4 nm) might be used as an optical probe for intracellular oxygen (O2) in cultured cells. QD580 was successfully introduced in cultured COS-7 cells by incubating cells with 10 nM QD580 for 5-60 min at 37°C. Cells were exposed to 20 % O2 (0.5 h), then 0.5 % O2 or 20 % O2 (1 h), and finally 20 % O2 (0.5 h) gases. We found significant increases in the fluorescence intensity at 0.5 % O2. However, when compared with QD580 in buffer solution, QD580 fluorescence in cells was considerably weak and vulnerable to repeated excitation light exposures. The present study demonstrated the potential of L-cysteine-capped CdTe QDs as a nanoscale probe for intracellular O2 in cultured cells. Further improvement of the QD is necessary for quantitative assessment of O2 in the cell.
authors.affiliation: Advanced Technology Fusion, Graduate School of Science and Engineering, Saga University, Honjo 1, Saga, 840-8502, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Higashi
authors.affiliation: Laboratory for Nano-Bio Probes, RIKEN Quantitative Biology Center, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Jin
authors.affiliation: Advanced Technology Fusion, Graduate School of Science and Engineering, Saga University, Honjo 1, Saga, 840-8502, Japan. eiji@cc.saga-u.ac.jp.
authors.forename: Eiji
authors.initials: E
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism; D010316:Particle Size; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D003545:Cysteine; D010100:Oxygen