[ChemPhyscChem] Rapid acquisition of x-ray scattering data from droplet-encapsulated protein systems
Encapsulating reacting biological or chemical samples in microfluidic droplets has the great advantage over 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.
Oliva Saldanha, Rita Graceffa, Clement Hemonnot, Christiane Ranke, Gerrit Brehm, Marianne Liebi, Benedetta Marmiroli, Britta Weinhausen, Manfred Burghammer, Sarah Koester