title: Rapid Acquisition of X-Ray Scattering Data from Droplet-Encapsulated Protein Systems.
abstract: Encapsulating reacting biological or chemical samples in microfluidic droplets has the great advantage over single-phase flows of providing separate reaction compartments. These compartments can be filled in a combinatoric way and prevent the sample from adsorbing to the channel walls. In recent years, small-angle X-ray scattering (SAXS) in combination with microfluidics has evolved as a nanoscale method of such systems. Here, we approach two major challenges associated with combining droplet microfluidics and SAXS. First, we present a simple, versatile, and reliable device, which is both suitable for stable droplet formation and compatible with in situ X-ray measurements. Second, we solve the problem of "diluting" the sample signal by the signal from the oil separating the emulsion droplets by multiple fast acquisitions per droplet and data thresholding. We show that using our method, even the weakly scattering protein vimentin provides high signal-to-noise ratio data.
authors.affiliation: Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.
authors.forename: Oliva
authors.initials: O
authors.lastname: Saldanha
authors.affiliation: Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.|Current address: European XFEL GmbH, 22869, Schenefeld, Germany.
authors.forename: Rita
authors.initials: R
authors.lastname: Graceffa
authors.affiliation: Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.
authors.forename: Clément Y J
authors.initials: CYJ
authors.lastname: Hémonnot
authors.affiliation: Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Ranke
authors.affiliation: Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Brehm
authors.affiliation: Paul Scherrer Institute, 5232, Villigen, Switzerland.|Current address: MAX IV Laboratory, Lund University, 221-00, Lund, Sweden.
authors.forename: Marianne
authors.initials: M
authors.lastname: Liebi
authors.affiliation: Institute of Inorganic Chemistry, Graz University of Technology, 8010, Graz, Austria.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Marmiroli
authors.affiliation: European Synchrotron Radiation Facility, 38000, Grenoble, France.|Current address: European XFEL GmbH, 22869, Schenefeld, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Weinhausen
authors.affiliation: European Synchrotron Radiation Facility, 38000, Grenoble, France.|Department of Analytical Chemistry, Ghent University, 9000, Ghent, Belgium.
authors.forename: Manfred
authors.initials: M
authors.lastname: Burghammer
authors.affiliation: Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.
authors.forename: Sarah
authors.identifier: http://orcid.org/0000-0002-0009-1024
authors.initials: S
authors.lastname: Köster
mesh_terms: D046210:Microfluidic Analytical Techniques; D010316:Particle Size; D011506:Proteins / Q000737:chemistry*; D053838:Scattering, Small Angle; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D011506:Proteins
keywords: cytoskeletal intermediate filaments; microfluidics; small-angle X-ray scattering; vimentin; water-in-oil emulsions