A disposable on-chip microvalve and pump for programmable microfluidics.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Assay Development

Background:

• Enzyme-linked immunosorbent assay (ELISA) requires precise reagent handling for accurate results.
• Existing lab-on-a-chip (LOC) platforms often face challenges in cost-effective and programmable multi-reagent control.
• Polydimethylsiloxane (PDMS) offers biocompatibility and ease of fabrication for microfluidic devices.

Purpose of the Study:

• To design and develop a low-cost PDMS micro-pump and micro-valve system for programmable reagent control on a LOC platform.
• To enable automated multi-step ELISA procedures using the developed microfluidic system.
• To demonstrate the system's capability in detecting a clinically relevant biomarker.

Main Methods:

• Fabrication of a PDMS micro-pump and micro-valve system actuated by a single roller bar and microprocessor.
• Characterization of the micro-pump's performance, including minimum controllable fluid volume (1 μL).
• Programming the micro-valves to automate multi-step ELISA procedures on the LOC device.

Main Results:

• The micro-pump and -valve system precisely controlled multiple reagents for automated ELISA.
• Successful detection of cardiac troponin T (cTnT) at a concentration of 19.40 pg/mL using the LOC device.
• Demonstrated the ability to actuate a series of solutions in a controlled manner for complex bioassays.

Conclusions:

• The developed low-cost PDMS micro-pump and -valve system offers precise and programmable control of reagents for LOC bioassays.
• This technology facilitates automated multi-step ELISA procedures, improving efficiency and accuracy.
• The system shows broad applicability for various lab-on-a-chip based immunoassays and diagnostic applications.