3D printed SAXS chamber for controlled in-situ dialysis and optical characterization

Ehm, T.; Philipp, J.; Barkey, M.; Ober, M.; Brinkop, A. T.; Simml, D.; von Westphalen, M.; Nickel, B.; Beck-Barkai, R.; Raedler, J. O.

doi:10.1101/2022.04.19.488724

bioRxiv · 10.1101/2022.04.19.488724

3D printed SAXS chamber for controlled in-situ dialysis and optical characterization

Ehm, T.·Philipp, J.·Barkey, M.·Ober, M.·Brinkop, A. T.·Simml, D.·von Westphalen, M.·Nickel, B.·Beck-Barkai, R.·Raedler, J. O.

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Abstract

3D printing changes the scope of how samples can be mounted for small angle X-ray scattering (SAXS). In this paper we present a 3D printed X-ray chamber, which allows for in-situ exchange of buffer and in-situ optical transmission spectroscopy. The chamber is made of cyclic olefin copolymers (COC), including COC X-ray windows providing ultra low SAXS background. The design integrates a membrane insert for in-situ dialysis of the 100 {micro}l sample volume against a reservoir, which enables measurements of the same sample under multiple conditions using an in-house X-ray setup equipped with a 17.4 keV molybdenum source. We demonstrate the designs capabilities by measuring reversible structural changes in lipid and polymer systems as a function of salt concentration and pH. In the same chambers optical light transmission spectroscopy was carried out measuring optical turbidity of the mesophases and local pH values using pH-responsive dyes. Microfluidic exchange and optical spectroscopy combined with in-situ X-ray scattering enables vast applications for the study of responsive materials.

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Ehm, T., Philipp, J., Barkey, M., Ober, M., Brinkop, A. T., Simml, D., von Westphalen, M., Nickel, B., Beck-Barkai, R., Raedler, J. O.. 2022-04-19. 3D printed SAXS chamber for controlled in-situ dialysis and optical characterization. https://doi.org/10.1101/2022.04.19.488724

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