title: Sensitive Detection of Cell Surface Membrane Proteins in Living Breast Cancer Cells Using Multicolor Fluorescence Microscopy with a Plasmonic Chip.
abstract: A plasmonic chip was applied to live cancer cell imaging. The epithelial cell adhesion molecule (EpCAM) is a surface marker that can be used to classify breast cancer cell lines into distinct differentiation states. EpCAM and the nuclei of two kinds of living breast cancer cells, MDA-MB231 and MCF-7, were stained with allophycocyanin (APC)-labeled anti-EpCAM antibody and 4',6-diamidino-2-phenylindole (DAPI), respectively, and the cells were scattered on either a plasmonic chip (metal-coated wavelength-scale grating substrate) or a control glass slide. Multicolor fluorescence microscopic imaging allowed fluorescence images of APC-EpCAM to be obtained on the plasmonic chip that were more than 10 times brighter compared with those on the glass slide. In contrast, in the fluorescence images of DAPI-stained nuclei, no difference in brightness was observed between substrates. The fluorescence enhancement of APC-EpCAM in the cell membrane in contact with the plasmonic chip is thought to be due to the excitation of APC molecules localized within the surface plasmon field. Analysis of the cross section of a fluorescence image revealed a distribution of EpCAM at a higher level of fluorescence in the center of the cell image because of contact between the cell membrane and the plasmonic chip. In contrast, fluorescence images of APC-EpCAM taken on a glass slide were so dark that only the outline of the cell was characterized. The plasmonic chip thus constitutes a simple and powerful tool for analyzing the distribution and kinetics of surface marker proteins in cell membranes contacting the chip.
authors.affiliation: Kwansei Gakuin University , 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.|AIST , 1-8-31 Midorigaoka, Ikeda, Osaka 563-8377, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Tawa
authors.affiliation: AIST , 2217-14 Hayashi-cho, Takamatsu, Kagawa 761-0395, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Yamamura
authors.affiliation: Kwansei Gakuin University , 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.|AIST , 1-8-31 Midorigaoka, Ikeda, Osaka 563-8377, Japan.
authors.forename: Chisato
authors.initials: C
authors.lastname: Sasakawa
authors.affiliation: AIST , 2217-14 Hayashi-cho, Takamatsu, Kagawa 761-0395, Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Shibata
authors.affiliation: AIST , 2217-14 Hayashi-cho, Takamatsu, Kagawa 761-0395, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kataoka
mesh_terms: D000951:Antigens, Neoplasm; D001943:Breast Neoplasms; D015815:Cell Adhesion Molecules; D045744:Cell Line, Tumor; D002470:Cell Survival; D000071858:Epithelial Cell Adhesion Molecule; D006801:Humans; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D008565:Membrane Proteins
keywords: breast cancer cells; grating; living cell; microscopy; multicolor fluorescence imaging; plasmon