Experimental viscoelasticity of physiological protein solutions

Physiological proteins such as fibrinogen and albumin are key biomarkers in diseases like chronic obstructive pulmonary disease (COPD), cardiovascular conditions, and sepsis. Studying the rheology of these proteins not only enhances clinical understanding but also provides a valuable framework to test polymer physics theories, particularly those describing flexible polymers in biologically relevant conditions. However, experimental characterization, especially of elasticity, remains limited due to measurement challenges. In this study, we employ the μ-rheometer microfluidic rheometer to systematically investigate blood plasma with varying fibrinogen concentrations and bovine serum albumin solutions. We found that the protein data can either be described by models for suspension of rigid spheres or by models for flexible polymers. We further demonstrate the clinical utility of these rheological parameters by applying them as rheological biomarkers to patients with acute exacerbation of COPD (AECOPD) in a UK tertiary hospital. Our study effectively connects fundamental polymer physics concepts with clinical diagnostics, underscoring the potential of protein rheology research to enhance healthcare monitoring and therapeutic strategies.