Observation of mammalian living cells with femtosecond single pulse illumination generated by a soft X-ray free electron laser

Abstract

Soft X-ray transmission microscopy is a powerful tool for visualizing cellular structures due to the natural contrast between organic material and water, but radiation damage has hindered its application to living cells. We have developed a soft X-ray microscope using femtosecond pulse illumination generated by a soft X-ray free electron laser, with which structural change of cells caused by radiation damage is negligible. Employing Wolter mirrors for illumination and objective optics allowed us to perform soft X-ray imaging with a large field of view, enabling observation of mammalian cells. We successfully captured images of living cells in a culture medium visualizing their carbon distribution. The broad wavelength-tunability of soft X-ray free electron lasers, in conjunction with the achromaticity of Wolter mirrors, enabled wavelength resolved cellular imaging.