Microfluidic valve with cored glass microneedle for microinjection.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Instrumentation

Background:

• Accurate microinjection is crucial for various biological and chemical applications.
• Existing microinjection systems often lack precise control over very small fluid volumes.
• Development of integrated microfluidic devices is essential for advanced manipulation tasks.

Purpose of the Study:

• To design and fabricate a novel microinjection device.
• To integrate a polydimethylsiloxane (PDMS)-based microvalve with a glass microneedle for precise fluid control.
• To evaluate the performance of the device for controlling low-volume fluid transfer.

Main Methods:

• Fabrication of a glass microneedle using traditional micropipette pulling.
• Construction of a PDMS-based microvalve with a two-level geometry for enhanced low-flow control.
• Integration of the microvalve with the microneedle to regulate fluid flow via manually supplied pneumatic pressure.
• Characterization of the pressure-flow relationship and valve 'ON/OFF' stability.

Main Results:

• The integrated device successfully controlled very small fluid volumes (>1 nl).
• The PDMS microvalve demonstrated stable 'ON/OFF' operation in response to pneumatic pressure changes.
• The two-level valve geometry improved control at low flow rates.
• Simultaneous monitoring confirmed reliable valve performance.

Conclusions:

• The developed microinjection device offers precise control over sub-nanoliter fluid volumes.
• The integrated PDMS microvalve provides a stable and effective mechanism for microfluidic flow regulation.
• This technology has potential applications in fields requiring high-precision liquid handling.