Paper Number
BL22                         My Program 

Session
Biological, Living, Active, and Directed Systems

Title
Simultaneous measurement of thermophoretic and Brownian particle motion in linearly viscoelastic non-Newtonian fluids using multiple particle tracking microrheology

Presentation Date and Time
October 16, 2024 (Wednesday) 5:05

Track / Room
Track 3 / Waterloo 5

Authors (Click on name to view author profile)

1. Hasanova, Nazrin (Lehigh University, Chemical and Biomolecular Engineering)
2. Roffin, Maria Chiara (Lehigh University, Department of Chemical and Biomolecular Engineering)
3. Cheng, Xuanhong (Lehigh University, Department of Materials Science and Engineering)
4. Schultz, Kelly M. (Purdue University, Davidson School of Chemical Engineering)
5. Gilchrist, James F. (Lehigh University, Department of Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Nazrin Hasanova¹, Maria Chiara Roffin¹, Xuanhong Cheng², Kelly M. Schultz³ and James F. Gilchrist^1
1Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA; ²Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA 18015; ³Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907

Speaker / Presenter 
Hasanova, Nazrin

Keywords
experimental methods; directed systems; low gravity research; non-Newtonian fluids; particles; particualte systems; polymer solutions; polymers; space applications

Text of Abstract
Processing of biological samples for separation and detection of viral particles may be time- and resource-intensive, making monitoring health challenging in locations with limited laboratory access. We aim to design resource-efficient particle separation techniques that quantify the viral load by separating and concentrating viruses from a biological sample. We use thermophoresis, directional motion of charged colloidal particles in response to a temperature gradient, to drive the separation of micron-sized particles from a bulk solution in a small sample. Using 2D multiple particle tracking microrheology (MPT), we capture and quantify motion of particles and relate it to material rheological properties. With MPT measurements of particles in a 1D thermal gradient, we can simultaneously measure local temperature-dependent fluid viscosity and thermophoretic particle velocity. Precise local rheology measurements are essential for optimizing thermophoresis-based separation in complex biological fluids. We demonstrate technique’s reliability by accurately measuring viscosity in solutions of increasing glycerol concentrations while simultaneously measuring particle thermophoretic velocity. Likewise, we measure thermophoretic motion in non-Newtonian solutions of various molecular weights of poly(ethylene oxide) below and above the overlap concentration. We correlate thermophoretic particle velocity with measured local viscosity and quantify the differences in thermophoretic diffusion across two dilution regimes of linearly viscoelastic fluids. By measuring how temperature-dependent fluid viscosity affects the extent of thermophoretic particle diffusion, we can optimize thermophoresis-based separation in complex fluids. This novel approach has the potential to both advance thermophoresis-based separations techniques and improve the design of more robust bioseparation techniques.