A Comprehensive Brownian Dynamics Approach for the Determination of Non-ideality Parameters from Analytical Ultracentrifugation

Uttinger, Maximilian J.; Wawra, Simon. E.; Guckeisen, Tobias; Walter, Johannes; Bear, Andreas; Thajudeen, Thaseem; Sherwood, Peter J.; Smith, Ana Sunčana; Wagemans, Anja M.; Stafford, Walter F.; Peukert, Wolfgang (2019) A Comprehensive Brownian Dynamics Approach for the Determination of Non-ideality Parameters from Analytical Ultracentrifugation. Langmuir, 35 (35). pp. 11491-11502. ISSN 0743-7463

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Official URL: https://pubs.acs.org/doi/10.1021/acs.langmuir.9b01...

Abstract

Brownian dynamics (BD) has been applied as a comprehensive tool to model sedimentation and diffusion of nanoparticles in analytical ultracentrifugation (AUC) experiments. In this article, we extend the BD algorithm by considering space-dependent diffusion and solvent compressibility. With this, the changes in the sedimentation and diffusion coefficient from altered solvent properties at increased pressures are accurately taken into account. Moreover, it is demonstrated how the concept of space-dependent diffusion is employed to describe concentration-dependent sedimentation and diffusion coefficients, in particular, through the Gralen coefficient and the second virial coefficient. The influence of thermodynamic nonideality on diffusional properties can be accurately simulated and agree with well-known evaluation tools. BD simulations for sedimentation equilibrium and sedimentation velocity (SV) AUC experiments including effects of hydrodynamic and thermodynamic nonideality are validated by global evaluation in SEDANAL. The interplay of solvent compressibility and retrieved nonideality parameters can be studied utilizing BD. Finally, the second virial coefficient is determined for lysozyme from SV AUC experiments and BD simulations and compared to membrane osmometry. These results are in line with DLVO theory. In summary, BD simulations are established for the validation of nonideal sedimentation in AUC providing a sound basis for the evaluation of complex interactions even in polydisperse systems.

Item Type:

Article

Additional Information:

M.J.U. and W.P. gratefully acknowledge funding of the German Research Foundation through the DFG project PE 427/33-1. T.G. and W.P. gratefully acknowledge funding of the German Research Foundation via the priority program DiSPBiotech (SPP 1934).

Uncontrolled Keywords:

Transport properties ; Hydrodynamics ; Diffusion Sedimentation Solvents

Subjects:

NATURAL SCIENCES > Physics

Divisions:

Division of Physical Chemistry

Projects: