A viscosity measurement technique for ultra-low sample volumes

Area of Science:

• Fluid Mechanics
• Rheology
• Biophysics

Background:

• Accurate viscosity measurement is crucial for understanding fluid behavior.
• Traditional methods can be limited by sample volume and viscosity range.
• Biological fluids often present challenges due to low viscosity and small sample sizes.

Purpose of the Study:

• To develop a novel, sensitive method for measuring liquid viscosity.
• To utilize thin film fluid mechanics for quantitative viscosity determination.
• To provide a technique suitable for low-viscosity and small-volume biological samples.

Main Methods:

• A drop of sample is spread on a substrate using a blade.
• The resulting thin film thickness is governed by the capillary number.
• The length of the liquid smear is correlated with the fluid's viscosity.

Main Results:

• The length of the smear, for a fixed sample volume, is directly related to the capillary number.
• This relationship provides a reliable measure of fluid viscosity.
• The technique demonstrates sensitivity to small changes in viscosity.

Conclusions:

• The described method offers a unique and effective approach to viscosity measurement.
• It is particularly advantageous for analyzing biological fluids like blood.
• This technique can serve as a non-specific screening tool for various medical conditions and treatments.