Precise Control of Micropipette Flow Rate for Fluorescence Imaging in In Vivo Micromanipulation.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Optical Imaging

Background:

• Accurate micropipette flow control is essential for in vivo fluorescence imaging and micromanipulation.
• Current manual methods and commercial systems lack precision and quantitative pressure-flow relationships.

Purpose of the Study:

• To develop a closed-loop pressure regulation system for precise micropipette flow control.
• To establish a quantitative pressure-flow relationship for microfluidic applications.

Main Methods:

• Developed a closed-loop pressure regulation system with 1 Pa-level control resolution.
• Utilized a droplet-based method for quantitative calibration of the pressure-flow relationship.
• Validated system performance in a brain-slice environment for fluorescence imaging.

Main Results:

• Established a linear pressure-flow relationship with a gain of 4.846 × 10-17m3·s-1·Pa-1 (R² > 0.99).
• Achieved target outlet flow rates with a control error below 10 fL/s.
• Maintained stable fluorescence imaging with intensity fluctuations around 1.3%.

Conclusions:

• The developed system provides stable, precise, and reproducible flow regulation for in vivo micromanipulation.
• Offers a valuable tool for advanced biological research requiring accurate fluid delivery.
• Overcomes limitations of existing methods in microfluidic flow control and calibration.