Simple manual roller pump-driven valve-free microfluidic solution exchange system for urgent bioassay

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Microfluidic devices offer miniaturized platforms for various applications.
• Efficient sequential solution exchange is crucial for complex bioassays.
• Existing microfluidic systems can be complex and expensive to operate.

Purpose of the Study:

• To develop a simple, valve-free microfluidic system for sequential solution exchange.
• To demonstrate the system's utility in performing a protein bioassay.
• To create a low-cost, user-friendly platform for point-of-care diagnostics.

Main Methods:

• A polydimethylsiloxane (PDMS)/glass microfluidic device was fabricated with a reaction chamber and micro-flow channels.
• A manual roller pump (MRP) was used for sequential solution injection and withdrawal via air pressure manipulation.
• Surface hydrophobicity effects on solution exchange were investigated.
• A sandwich fluorescence immunoassay for human interleukin 2 (IL-2) was performed.

Main Results:

• The MRP-driven system enabled efficient sequential solution exchange without valves.
• Human interleukin 2 (IL-2) was detected within 20 minutes.
• The immunoassay achieved a detection limit of 80 pg mL⁻¹ and a dynamic range of 125 pg mL⁻¹ to 2.0 ng mL⁻¹.
• The system demonstrated suitability for analytical bioassays.

Conclusions:

• A simple, user-friendly, and valve-free microfluidic system was successfully developed.
• The device facilitates rapid and cost-effective protein detection.
• This technology holds potential for low-cost bioassays in emergency and resource-constrained situations.