SAMOP 2023 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 59: Poster IV
Q 59.70: Poster
Thursday, March 9, 2023, 16:30–19:00, Empore Lichthof
Rapid Dilution Mass Photometry — •Carla M. Brunner1, Emanuel Pfitzner2, and Philipp Kukura2 — 1Friedrich-Alexander-Universität Erlangen-Nürnberg — 2Department of Chemistry, University of Oxford
Mass Photometry (MP) is an optical method based on interferometric scattering microscopy that enables label-free detection of single proteins in solution based on their scattering contrast. Multiple species in a heterogeneous solution can be differentiated by their molecular mass and consequently, binding affinities can be determined. The study of weak interactions calls for high sample concentrations on the order of μM whereas MP requires low concentrations in the nM range.
Developing a rapid dilution method, we explored how the application of MP can be extended beyond these current constraints. Using microcapillaries, we show that we can inject high concentration solutions of transferrin and the IgG antibody 17b into a buffer medium whereupon the sample is diluted by several orders of magnitude within seconds, maintaining the possibility of single-particle detection and the capability to reliably distinguish different species. Nevertheless, carrying out further experiments with a wider range of protein species revealed that some improvements to the setup are required in order to be able to use our methodology more broadly. Measurements performed with HspB1 showed that aggregation of proteins in the capillary tip inhibits the precise determination of mass distributions. A careful investigation of our findings allowed us to pin down current limitations and suggest necessary modifications.