A Novel Device for the Quantification of Synovial Fluid Viscosity Via Magnetic Deflection

Area of Science:

• Biomedical Engineering
• Rheumatology
• Fluid Mechanics

Background:

• Synovial fluid viscosity changes are indicative of joint disease.
• Current point-of-care diagnostic methods for synovial fluid mechanics are limited.
• Previous work showed magnetic particle translation as a surrogate marker for synovial fluid mechanics.

Purpose of the Study:

• To investigate magnetic particle stream deflection as a method to quantify synovial fluid mechanics.
• To correlate particle stream deflection with changes in fluid viscosity.
• To develop a principle for point-of-care diagnostics of joint disease.

Main Methods:

• Designed a flow device to observe magnetic particle streams in flowing synovial fluid.
• Measured particle stream deflection in Newtonian glycerol solutions of known viscosity.
• Assessed particle deflection in bovine synovial fluid degraded by ultrasonication.

Main Results:

• A strong correlation (R² = 0.987) was found between particle deflection and glycerol solution viscosity.
• A significant correlation (R² = 0.7045) was observed between particle deflection and ultrasonic degradation of synovial fluid.
• Particle deflection increased with decreased viscosity, as predicted.

Conclusions:

• Magnetic particle stream deflection is a viable method for assessing synovial fluid mechanics.
• This principle can be applied to develop point-of-care devices for joint disease detection.
• The method is advantageous as it does not require particle separation and works under simple flow conditions.