Design Award

• Design Excellence Award Winner

Project Overview

Blood viscosity has been shown to have significant implications in a clinical setting. Changes in blood viscosity can be related to inflammation, tissue injuries, cardiovascular and neoplastic disease. Current methods to characterize blood viscosity involve centrifuging the blood plasma out of whole blood and measuring the viscosity of the plasma alone using capillary or falling-sphere viscometers. Blood plasma by itself is considered a Newtonian fluid, with its viscosity remaining independent of shear-rate and temperature. Measuring changes in blood plasma viscosity can give physicians further insight into the presence or progression of diseases that lead to changes in clotting cascade activation, immunoglobulin concentration, inflammatory biomarkers. However, while highly sensitive to multiple diseases, plasma viscosity is lacking in disease specificity, leading to its underutilization in the clinical workflow in a hospital.

The measurement of whole blood viscosity, on the other hand, incorporates the highly-compressible and aggregating element of red blood cells (RBCs). As a result, whole blood is considered a shear-thinning, non-Newtonian fluid, with viscosities that change with temperature and velocity. Measuring the response of whole blood viscosity across different temperatures and velocities can potentially offer more discriminating information about certain disease process, leading to increased specificity in disease diagnosis or progression.

Arranging and measuring multiple combinations of velocity and temperature of blood can be labor-intensive and prohibitively time consuming due to the rapid onset of coagulation once blood is removed from the patient. Our proposal was to overcome this challenge by leveraging advances in microfluidic technology to make temperature adjustments and viscosity measurements within seconds of leaving the blood vessel. Microfluidic devices are small and inexpensive, necessitating only minimal sample volumes and can be multiplexed in a manner that can run multiple studies simultaneously. The high surface-area to volume ratio associated with using microfluidics allows for near instantaneous heating of blood samples and associated viscosity measurements. The rapid execution of the viscosity measurements will ensure that the viscosity changes are derived exclusively from flow and temperature, and not platelet activation from oxygen exposure.

A microfluidic viscometer was designed along with a temperature control system. The current parallel channel microfluidic device prototype can measure the viscosity of water and ethanol accurately. However, design modifications are required to ensure the device is fully compatible with blood. The heating element in its current state has the ability to heat through the desired temperature range, 37 ºC to 70 ºC.

In this semester of BME design, we are concentrating on optimizing the design of the microfluidic device in order to increase the sensitivity and accuracy of the viscosity measurement. With these modifications as well as improvements in the heating element, we will be able to characterize whole blood viscosity over a range of temperatures. Ultimately, this will provide clinicians with additional information during disease diagnosis as means to improve patient care.

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Contact Information

Team Members

• Christopher Patterson - Team Leader
• Tyler Lieberthal - Communicator
• Jared Warczytowa - BSAC
• Anthony Prostrollo - BWIG
• Ross Paulson - BPAG

Advisor and Client

• Prof. Paul Thompson - Advisor
• Prof. Chris Brace - Client
• Jason Chiang - Alternate Contact

Related Projects

• Spring 2015: Hemorheological-based microfluidic chip platform for measuring blood viscosity
• Fall 2014: Hemorheological-based microfluidic chip platform for measuring blood viscosity
• Spring 2014: Hemorheological-based microfluidic chip platform for measuring blood viscosity