Slow and fluctuating dynamics in high concentration BSA protein solutions

Particle tracking microrheology and dynamic light scattering of bovine serum albumin (BSA) solutions (1-55 g/dl) revealed novel behavior at high concentrations. The increase in slow relaxation times with concentration becomes less pronounced, revealing an additional aging regime already observed in very soft colloids. At the highest concentrations, slow relaxation times showed significant temporal fluctuations – a phenomenon previously seen in soft colloids but newly documented in concentrated BSA solutions.

Legend:
The slow relaxation time, τ2, normalized by the fast relaxation time, τ1, of the semi-diluted regime, increases over nearly 4 decades across the wide range of concentrations. At the highest concentrations, the increase in the τ2/τ1 ratio is observed to slow down.

Reference:
Slow and fluctuating dynamics in high concentration BSA protein solutions, A. Briole et B. Abou, J. Chem. Phys. 162, 135102 (2025)