Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Charged Soft Matter II
CPP 40.8: Talk
Wednesday, March 18, 2015, 11:15–11:30, PC 203
The effect of variable charge patterns: interactions and phase behaviour of a non-monoclonal antibody mixture — •Stefano Da Vela1, Fajun Zhang1, Michael Sztucki2, Ralf Schweins3, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen — 2ESRF, Grenoble, France — 3ILL, Grenoble, France
Bovine γ-globulin is an easily available mixture of antibodies (immunoglobulins) with different specificities: this implies that the constituents feature a manifold of surface charge distribution patterns. The main component is Immunoglobulin G (IgG), an anisotropic, Y-shaped protein. We aim to understand the relationship between the profusion of anisotropic charge driven interactions present in the system and the macroscopic phase behaviour. Solutions of γ-globulin in a wide range of protein volume fractions (0.001 up to 0.27) are investigated with and without added salts using predominantly turbidimetry, dynamic light scattering, small angle x-ray and neutron scattering. We show how the heterogeneity of the charge distribution in different proteins accounts for sample bidispersity and explains self-association and turbidity in γ-globulin dispersions at low ionic strengths. At high volume fractions, the repulsive component of the effective interaction is modelled considering protein anisotropy. Our work has potential applications in the stability enhancement of analogous therapeutic blood products.