SU-8 free-standing microfluidic probes

Area of Science:

• Microfabrication
• Materials Science
• Biotechnology

Background:

• SU-8 photoresist is widely used for microfabrication due to its excellent properties.
• Existing methods for releasing SU-8 microstructures can be complex and limit scalability.
• There is a need for robust and versatile fabrication processes for free-standing microfluidic devices.

Purpose of the Study:

• To present a novel, dry release process for fabricating free-standing SU-8 microfluidic probes.
• To demonstrate the versatility of the fabrication process for various applications, including impedance sensing.
• To enable convenient batch production of microfluidic devices with precise tip geometry.

Main Methods:

• Utilized thermal release tape for a dry, mechanical release of SU-8 micro-devices from a sacrificial layer.
• Developed two liquid interface designs for characterizing the SU-8 probes: integrated wells and external reservoirs.
• Functionalized SU-8 probes with metal thin-film electrodes for impedance sensing and developed an associated electronic interface.
• Investigated photolithography for creating perforations in SU-8 devices for diffusion-based solution sampling.

Main Results:

• Successfully fabricated free-standing SU-8 microfluidic probes with a dry release mechanism.
• Demonstrated the adaptability of the process for creating functionalized probes for impedance sensing.
• Developed versatile interface schemes for liquid handling and electronic measurements.
• Showcased the potential for batch production of microfluidic devices with controlled tip geometry.

Conclusions:

• The presented SU-8 fabrication process offers a convenient and scalable method for producing versatile free-standing microfluidic devices.
• The dry release technique simplifies device fabrication and enhances compatibility with various applications.
• The developed process facilitates the integration of sensing functionalities and precise control over device geometry.