The viscosity of protein solutions often experiences a sudden increase when the concentration reaches a threshold value. For the vast majority of proteins it is currently hard to predict the exact location of this liquid-solid transition from the solution properties at low concentration only. In view of the high cost/low availability of highly interesting proteins such as antibodies, where a viscosity increase can inhibit the injection of effective doses, or eye-lens proteins, where the physiological concentration is naturally very high to achieve the refractive properties needed, it is commonly not viable to investigate this type of systems using macroscopic methods such as classical rheology due to the large sample volumes needed. Instead we use Dynamic Light Scattering (DLS) based microrheology where we can extract information about the viscoelastic behaviour of the various protein solutions by measuring the motion of inert tracer particles embedded in a small sample volume. We also work on the synthesis of tracer particles that meet all requirements for a systematic investigation of the viscoelastic properties of different protein solutions and mixtures as a function of concentration and solvent conditions.

People:Tommy Garting, Nicholas Skar-Gislinge, Anna Stradner.

Contact person: Anna Stradner