Researcher(s)
- Diana Schryver, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Norman Wagner, Chemical and Biomolecular Engineering, University of Delaware
Abstract
Irregularities in the rheology of blood act as markers for cardiovascular diseases, which are the leading cause of mortality in the world. At low shear rates, red blood cells aggregate into rouleaux structures that give non-Newtonian behavior to blood, causing viscoelastic, thixotropic, and shear-thinning behavior which varies based on the donor. Rheological irregularities at low shear regimes can be microscopically observed by suspending blood in a rectangular PDMS microfluidic channel connected to two open reservoirs, which allow for gravity-induced flow corresponding to differences in column height. The pressure drops produce a range of stresses within the device in conjunction with particle image velocimetry (PIV) in MATLAB to track particle velocities and shear rates, with the aim of determining a healthy range of fluid dynamics in blood for further diagnostic applications. Current measurements of blood rheology involve expensive bulk instruments that are not accessible in harsh environments, suggesting a need for a microfluidic device that requires small sample volumes for analysis while being portable and economically favorable. In this study, a blood simulant was formulated with water, glycerol, and xanthan gum for the purpose of developing a blood-like viscosity profile from pressure-driven microfluidic measurements recorded for PIV analysis at low shear regimes. The simulant was further characterized with a rheometer using cone-and-plate geometry to confirm rheological similarities to blood. The microfluidic device prioritizes a shift towards personalized diagnostics based on experimental data accounting for the complexity of blood.