Microfluidic sample delivery for serial crystallography using XFELs.

Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) is an emerging field for structural biology. One of its major impacts lies in the ability to reveal the structure of complex proteins previously inaccessible with synchrotron-based crystallography techniques and allowing time-resolved studies from femtoseconds to seconds. The nature of this serial technique requires new approaches for crystallization, data analysis, and sample delivery. With continued advancements in microfabrication techniques, various developments have been reported in the past decade for innovative and efficient microfluidic sample delivery for crystallography experiments using XFELs. This article summarizes the recent developments in microfluidic sample delivery with liquid injection and fixed-target approaches, which allow exciting new research with XFELs. Graphical abstract.