In situ observation of inner structures of biological cells with a soft X-ray microscope

Kado, Masataka; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Aoyama, Masato*; Tone, Shigenobu*; Shinohara, Kunio*

Soft X-ray wavelengths between absorption K-edges of Oxygen and Carbon (2.3 nm and 4.4 nm) are so called "water window" and the X-ray were well absorbed by Carbon and less absorbed by water. Soft X-ray microscope using the water window X-ray as the light source has advantage to be able to observe live biological cells without any artifacts and can observe fine structures of cells compared to the light microscope. Combining with bright and short-pulsed laser-plasma soft X-ray the soft X-ray microscope which named a laser-plasma soft X-ray microscope can observe live biological cells in situ without radiation damages. We have generated bright water window soft X-ray irradiating a high power laser with 1053 nm in wavelength, 20 J in pulse energy and 600 ps in pulse duration onto thin foiled gold targets. Cultivating biological cells directly on the PMMA photoresists in situ observation of live biological cells with the laser-plasma soft X-ray microscope has been realized.