Precise Dispensing Technology Using Electroformed Tubes for Micro-Volume Blood Diagnosis.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Clinical Diagnostics

Background:

• Precise liquid handling is essential for reliable blood diagnostic results, especially with limited sample volumes.
• Submicroliter and nanoliter dispensing accuracy is critical for microfluidic and point-of-care diagnostic devices.

Purpose of the Study:

• To develop a high-precision positive-displacement dispensing technique for submicroliter and nanoliter volumes.
• To evaluate the dispensing accuracy and stability of the developed technique.
• To demonstrate the feasibility of precise biochemical analysis using minimal blood volumes.

Main Methods:

• Development of a positive-displacement dispenser utilizing a nickel electroformed tube with high inner diameter accuracy.
• Evaluation of dispensing variation (100 nL) using a photometric method to determine optimal tube thickness and hydrophobic treatment.
• Colorimetric measurement of glucose concentration in animal-based control serum (100- and 200-nL) using enzymatic reactions.

Main Results:

• Optimized dispenser achieved a stable coefficient of variation (CV) of 1.3% (1.3 nL) for 100 nL dispensing with specific tube thickness and hydrophobic treatment.
• Accurate colorimetric measurement of glucose concentration demonstrated CVs of 6.36% at 100 nL and 3.23% at 200 nL.
• The dispenser ensures zero contamination and near-zero dead volume.

Conclusions:

• The developed positive-displacement dispenser enables highly precise nanoliter liquid handling for diagnostic applications.
• This technology facilitates accurate biochemical panel measurements from very small blood volumes, potentially revolutionizing point-of-care testing.
• The dispenser's features make it suitable for multi-panel clinical blood testing and research requiring minimal sample volumes.