title: Deep-UV biological imaging by lanthanide ion molecular protection.
abstract: Deep-UV (DUV) light is a sensitive probe for biological molecules such as nucleobases and aromatic amino acids due to specific absorption. However, the use of DUV light for imaging is limited because DUV can destroy or denature target molecules in a sample. Here we show that trivalent ions in the lanthanide group can suppress molecular photodegradation under DUV exposure, enabling a high signal-to-noise ratio and repetitive DUV imaging of nucleobases in cells. Underlying mechanisms of the photodegradation suppression can be excitation relaxation of the DUV-absorptive molecules due to energy transfer to the lanthanide ions, and/or avoiding ionization and reactions with surrounding molecules, including generation of reactive oxygen species, which can modify molecules that are otherwise transparent to DUV light. This approach, directly removing excited energy at the fundamental origin of cellular photodegradation, indicates an important first step towards the practical use of DUV imaging in a variety of biological applications.
authors.affiliation: Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Near-field Nanophotonics Research Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Currently with the Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Kumamoto
authors.affiliation: Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Nicholas Isaac
authors.initials: NI
authors.lastname: Smith
authors.affiliation: Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Near-field Nanophotonics Research Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawata
keywords: (170.3880) Medical and biological imaging; (260.5130) Photochemistry; (300.6540) Spectroscopy, ultraviolet
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