Integration of Soft X-ray Tomography and High Resolution Fluorescence Microscopy

Soft X-ray Tomography (SXT) is a relatively new synchrotron-based imaging technique for biologist to observe the ultrastructure insides cells. SXT uses the x-ray source in the so called "water window" region, which is between the K-edge absorption of carbon at 284 eV and K-edge absorption of oxygen at 543 eV. At these region, the absorption coefficient of oxygen (i.e. water) is much lower than carbon and nitrogen, which are the major biochemical constituents of biomolecules. Given this fact, SXT is able to produce high natural contrasts between cells and water as cells were only frozen without staining and processing Currently, SXT beamline and endstation are constructing at Taiwan Photon Source (TPS) in National Synchrotron Radiation Research Center (NSRRC). The SXT microscopy at TPS is designed with capillary condenser and an objective Fresnel zoneplate with spatial resolution of 15-30nm for 2D imaging and 50nm for 3D tomography.