SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Poster Session II

CPP 35.6: Poster

Wednesday, March 29, 2023, 11:00–13:00, P1

Depletion induced phase behavior and equilibrium clusters in charged BSA and HSA protein solutions — •Maximilian D. Senft, Fajun Zhang, and Frank Schreiber — Universität Tübingen, Germany

Understanding and predicting the phase behavior of proteins is an ongoing endeavor in many scientific research areas, including the pharmaceutical industry. In addition to crystallization, liquid-liquid phase separation and condensate formation, which includes equilibrium clusters, dense liquid droplets, fibrils, and gels, appear to be closely related to many pathological conditions. The formation of equilibrium protein clusters in solution requires an interaction potential with competing contributions, i.e., long-ranged repulsion and short ranged attraction. Bovine and human serum albumin (BSA and HSA) carry negative charges at neutral pH which provide a long-range electrostatic repulsion between proteins. The attractive potential can be generated via the depletion interactions introduced by the non-adsorbing polymer polyethylene glycol in protein solutions. By tuning the ionic strength, polymer size and concentration, the competing potential can be continuously adjusted, resulting in equilibrium protein clusters due to the subtle balance to the different contributions of the interaction potential. Having performed systematic small angle scattering measurements, on BSA and HSA, together with quantitative modeling combined with protein phase diagrams a better understanding of depletion induced protein phase behavior and cluster state can be provided.