[16p-2C-1~10] 4.2 Bio- and Medical Photonics

▲ [16p-2C-9] Lanthanide ions for suppressing photodegradation of biological cells under deep-ultraviolet light exposure

〇Yasuaki Kumamoto^1,2, Katsumasa Fujita¹, Nicholas Smith³, Satoshi Kawata^1,2 (1.Osaka Univ., 2.RIKEN, 3.iFReC)

Keywords:Deep-UV,Raman,Photodamage

We report that the trivalent ions of terbium, europium, and thulium can suppress molecular photodegradation in cells under deep-ultraviolet (DUV) exposure, due to energy transfer from DUV-excited molecules. Morphologies of the cells treated with these three lanthanide ions were sustained through DUV exposure, while cells without lanthanide ions treatment completely disappeared after DUV exposure. The quantitative measurements using resonance Raman scattering showed that the treatment of cells with lanthanide ions maintained twice or larger numbers of nucleobases available for optical measurements before photodegradation occurred. The lanthanide ions treatment increased resistance to repeated exposures of the cells, enabling repetitive DUV measurements of a cell. The combination of lanthanide ions treatment and argon purge further suppressed molecular photodegradation. Out of the three lanthanide ions, the combination of europium ions with argon purge gave the largest suppression effect, resulting in the highest signal-to-noise ratio in DUV Raman images of nucleobases in cells. The ability to suppress DUV photodegradation of biological samples may be extended to preventing specimen photodegradation in a variety of optical measurements.