Electrochemical hematocrit determination in a direct current microfluidic device.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Microfluidics

Background:

• Hematocrit (HCT) testing is crucial for blood donor screening and diagnosing various medical conditions.
• Existing HCT methods, such as microhematocrit and Coulter counters, present limitations including high cost, complexity, and environmental concerns.
• Point-of-care (POC) devices are sought after for rapid and accessible HCT determination.

Purpose of the Study:

• To introduce a novel, simple microfluidic system for point-of-care (POC) hematocrit (HCT) determination.
• To demonstrate the feasibility of using electrical current measurements within a microfluidic device for HCT analysis.
• To optimize parameters influencing current responses for accurate HCT measurement.

Main Methods:

• A microfluidic device with a single microchannel (180 μm x 70 μm x 10 mm) was designed for HCT testing.
• Electrical current responses of red blood cell (RBC) suspensions at various HCT concentrations (10-70 vol%) were measured under 100 V DC for 1 minute.
• Optimization of current responses involved addressing electrolysis bubbles and RBC adsorption by adding Triton X-100 and carbonizing electrode surfaces.

Main Results:

• Feasibility of the microfluidic system for HCT determination was shown across a range of RBC concentrations in both PBS and plasma.
• Linear trends between current responses and HCT concentrations were established.
• Optimization strategies effectively mitigated issues like electrolysis bubbles and irreversible RBC adsorption.

Conclusions:

• The developed simple microfluidic system demonstrates significant promise as a new platform for POC HCT devices.
• This approach offers a potentially cost-effective and user-friendly alternative to conventional HCT testing methods.
• Further development could lead to a widely applicable POC HCT testing solution.