Nanoliter viscometer for analyzing blood plasma and other liquid samples

Area of Science:

• Microfluidics
• Biomedical Engineering
• Analytical Chemistry

Background:

• Accurate viscosity measurement is crucial for diagnosing conditions like hyperviscosity syndrome.
• Traditional viscometers can be slow, expensive, and require large sample volumes.
• Microfluidic devices offer potential for miniaturized and efficient fluid analysis.

Purpose of the Study:

• To develop and validate a microfabricated nanoliter capillary viscometer.
• To enable rapid, accurate, and cost-effective viscosity measurements of small liquid volumes.
• To assess the device's utility for analyzing biological fluids, including patient plasma.

Main Methods:

• Utilized microfluidic channels (approx. 30 µm depth, 300 µm width) for capillary pressure-driven flow.
• Integrated on-chip components for measuring driving pressure and geometrical parameters.
• Self-calibration capabilities were incorporated into the silicon-glass hybrid device.

Main Results:

• Achieved viscosity measurements in under 100 seconds using only 600 nL of sample.
• Demonstrated accuracy of 3% when analyzing blood plasma from patients with hyperviscosity syndrome.
• Validated performance across a viscosity range of 1–5 cP, relevant for biological fluids.

Conclusions:

• The developed nanoliter capillary viscometer is self-calibrating, robust, and user-friendly.
• The device provides a rapid and precise method for viscosity determination.
• Potential widespread applications exist in clinical diagnostics, research laboratories, and personal healthcare.