Rheological Characterization of Respiratory Secretions in Severe SARS-CoV-2 (COVID-19) Infections

• Prof. Andrew J. Spakowitz, Depts. of Chemical Engineering and Materials Science & Engineering, Stanford University
• Sponsored by the Golden Gate Polymer Forum
• October 21st, 6:30-7:30 pm, Online via Zoom, $5 donation/Free, Registration required (registration deadline Oct. 19th @ 1pm)

Abstract: Thick, viscous respiratory secretions are common in severe cases of COVID-19 disease and greatly contribute to breathing difficulty. Understanding the polymeric composition and the rheological properties of these secretions can inform the development of treatments to improve the respiratory function of these patients. After measuring the composition of respiratory secretions collected from intubated COVID-19 patients and controls, we found that DNA content and hyaluronan content were greatly elevated in COVID-19 sputum. Across all patients, COVID-19 sputum exhibited a wide distribution in rheological properties, which were measured using dynamic light scattering microrheology. Respiratory secretions from COVID-19 patients had a statistically significant increase in storage moduli compared to healthy controls. We explored the possibility of reducing sputum viscosity by treating the aspirates enzymatically with hyaluronidase or DNase, which degrade hyaluronan and DNA, respectively. Interestingly, there was a strong positive correlation between the shear modulus of COVID-19 sputum and the effect of these enzymes. These results suggest that DNA and hyaluronan may be viable therapeutic targets in COVID-19 infection and could be targeted with FDA-approved enzymes already clinically used for other indications.

Bio: Prof. Spakowitz received his Ph.D. from CalTech, and is a Professor in both departments of Chemical Engineering and Materials Science & Engineering at Stanford University. The Spakowitz research group is engaged in projects that address fundamental chemical and physical phenomena underlying a range of biological processes and soft-material applications. Current research in his research group focuses on four main research themes: chromosomal organization and dynamics, protein self-assembly, polymer membranes, and charge transport in conducting polymers. These broad research areas offer complementary perspectives on chemical and physical processes, and they leverage this complementarity throughout their research. This approach draws from a diverse range of theoretical and computational methods, including analytical theory of semiflexible polymers, polymer field theory, continuum elastic mechanics, Brownian dynamics simulation, equilibrium and dynamic Monte Carlo simulations, and analytical theory and numerical simulations of reaction-diffusion phenomena. A common thread in the work is the need to capture phenomena over many length and time scales, and flexibility in research methodologies provides them with the critical tools to address these complex multidisciplinary problems.

http://web.stanford.edu/~ajspakow/