Chapter 9.3 X-ray diffraction imaging of whole cells

Coherent X-ray diffraction microscopy (CXDM) is a method for the determination of non-crystalline structures through the inversion of X-ray diffraction data. The method relies on a numerical phase-retrieval step which, utilizing oversampled diffraction data, requires that the diffracting object be finite and isolated. The high efficiency of this lensless technique means that it is well suited for imaging radiation-sensitive biological matter. Furthermore, the penetrating power of X-rays combined with the natural contrast provided by ‘water window’ photon energies make it feasible to image whole, unstained cells. The first two sections of this chapter provide a brief history of CXDM and an overview of the basic phase-retrieval methods. The following sections discuss the state-of-the-art capabilities for whole-cell imaging, the effects of radiation damage and the use of stereoscopic imaging for acquiring three-dimensional information with a minimum of radiation dose.

Keywords: coherent X-ray diffraction microscopy; phase retrieval; whole-cell imaging; radiation damage