Observation of non-equilibrium fluctuation in the shear-stress-driven hemoglobin aggregates

• Published in: The European physical journal. E, Soft matter and biological physics Vol. 46; no. 12; p. 131
• Main Authors: Kabiraj, A., Mallik, G., Dash, P. P., Kumari, P., Bandyopadhyay, M., Rath, S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2023; Springer Nature B.V
• Subjects: Biological and Medical Physics; Biophysics; Complex Fluids and Microfluidics; Complex Systems; Distribution functions; Equilibrium; Hemoglobin; Nanotechnology; Physics; Physics and Astronomy; Polymer Sciences; Probability distribution functions; Regular Article - Flowing Matter; Shear rate; Shear stress; Soft and Granular Matter; Surfaces and Interfaces; Theorems; Thin Films
• ISSN: 1292-8941; 1292-895X
• DOI: 10.1140/epje/s10189-023-00389-1

Non-equilibrium fluctuations caused by the rearrangement of hemoglobin molecules into an aggregate state under shear stress have been investigated experimentally. The flow response under the shear stress ( σ ) corroborates the presence of contrasting aggregate and rejuvenation states governed by entropy production and consumption events. From the time-dependent shear rate fluctuation studies of aggregate states, the probability distribution function (PDF) of the rate of work done is observed to be spread from negative to positive values with a net positive mean. The PDFs follow the steady-state fluctuation theorem, even at a smaller timescale than that desired by the theorem. The behavior of the effective temperature ( T eff ) that emerges from a non-equilibrium fluctuation and interconnects with the structural restrictions of the aggregate state of our driven system is observed to be within the boundary of the thermodynamic uncertainty. The increase in T eff with the applied σ illustrates a phenomenal nonlinear power flux-dependent aggregating behavior in a classic bio-molecular-driven system. Graphical abstract