A microfluidic device for kinetic optimization of protein crystallization and in situ structure determination

Recently microfluidic technologies have emerged as viable platforms for nano-volume protein crystallization screening.1-4 In particular, screening in nanoliter volume free interface diffusion (FID) reactors has been instrumental in the crystallization of a broad range of targets that had proven to be intractable by conventional screening techniques and has been successfully incorporated into academic and industrial structural biology efforts.5,6 However, crystals grown in nanoliter volume reactors may be of insufficient size for diffraction studies, and scale-up usually depends on growth kinetics that vary with reactor details.3,5 Moreover, previously reported microfluidic crystallization devices do not allow the post-crystallization addition of cryoprotectant necessary for diffraction studies at cryogenic temperatures.11 In this paper, we report a microfluidic device which provides a link between chip-based nanoliter volume crystallization screenin