IUCr journals

Diffractive imaging for periodic samples: retrieving one-dimensional concentration profiles across microfluidic channels

Acta Cryst. (2007). A63, 306–314 [doi:10.1107/S0108767307021903]

[microfluidic arrays] Left: Set-up to record X-ray small-angle scattering data for microfluidic arrays in transmission geometry. Right: The retrieved phase profiles across the channels reveal ordering effects in colloidal solutions.
Geometrical confinement can dramatically alter bulk properties of fluids like viscosity and density and may be used for the alignment and, eventually, crystallization of macromolecules. We present a technique to determine the concentration profiles across microfluidic channels using iterative phase-retrieval algorithms applied to small-angle-grating diffraction data. Currently 300–600 nm sized channels are sampled with a resolution in the 10 nm range. We plan to scale the technique down further and to study otherwise non-crystallizable macromolecules.

O. Bunk, A. Diaz, F. Pfeiffer, C. David, B. Schmitt, D.K. Satapathy and J.F. van der Veen