Serial femtosecond crystallography (SFX) with femtosecond X-ray pulses from X-ray freeelectron lasers (XFELs) offers a route to overcome radiation damage to small protein crystals via the 'diffraction-before-destruction' approach. A single-pulse X-ray exposure completely destroys individual crystals; therefore, fresh specimens must be supplied for subsequent X-ray pulses to continue data acquisition. A matrix method using protein crystal carriers, such as grease and oil-free hydrogel media, has been developed for serial sample loading. The microextrusion technique employing matrices allows the structure determination of a wide variety of proteins with low sample consumption, typically less than 1 mg. This offers new opportunities for time-resolved studies of light-driven structural changes and chemical dynamics using pumpprobe techniques at XFEL and synchrotron facilities.

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