title: Spectral fingerprinting of individual cells visualized by cavity-reflection-enhanced light-absorption microscopy.
abstract: The absorption spectrum of light is known to be a "molecular fingerprint" that enables analysis of the molecular type and its amount. It would be useful to measure the absorption spectrum in single cell in order to investigate the cellular status. However, cells are too thin for their absorption spectrum to be measured. In this study, we developed an optical-cavity-enhanced absorption spectroscopic microscopy method for two-dimensional absorption imaging. The light absorption is enhanced by an optical cavity system, which allows the detection of the absorption spectrum with samples having an optical path length as small as 10 μm, at a subcellular spatial resolution. Principal component analysis of various types of cultured mammalian cells indicates absorption-based cellular diversity. Interestingly, this diversity is observed among not only different species but also identical cell types. Furthermore, this microscopy technique allows us to observe frozen sections of tissue samples without any staining and is capable of label-free biopsy. Thus, our microscopy method opens the door for imaging the absorption spectra of biological samples and thereby detecting the individuality of cells.
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Arai
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Pathology and Cell Regulation, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Minamikawa
authors.affiliation: Department of Pathology and Cell Regulation, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Takamatsu
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Nagai
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D008027:Light; D051379:Mice; D008853:Microscopy / Q000379:methods*; D041681:NIH 3T3 Cells; D016716:PC12 Cells; D025341:Principal Component Analysis; D051381:Rats; D059010:Single-Cell Analysis / Q000379:methods*