Photodefinable polydimethylsiloxane (PDMS) for rapid lab-on-a-chip prototyping

Area of Science:

• Materials Science
• Microfluidics
• Photochemistry

Background:

• Polydimethylsiloxane (PDMS) is widely used in microfluidics.
• Existing PDMS patterning methods can be complex and require specialized equipment.
• There is a need for simpler, faster, and more accessible PDMS fabrication techniques.

Purpose of the Study:

• To introduce a new, simple, and direct photopatterning method for PDMS.
• To demonstrate the fabrication of microfluidic devices and shadow masks using this method.
• To optimize the process parameters for reliable feature generation.

Main Methods:

• Utilizing benzophenone as a photoinitiator in a PDMS mixture (photoPDMS).
• Employing UV light (below 365 nm) for photopatterning under ambient light.
• Fabricating microfluidic channels and thin free-standing films with through patterns.

Main Results:

• Successfully patterned PDMS with features around 100 micrometers.
• Fabricated microfluidic channels and characterized them using fluorescence microscopy.
• Created thin, free-standing patterned films used as effective shadow masks.

Conclusions:

• The photoPDMS process offers a fast, simple, and master-free method for PDMS patterning.
• This technique enables the rapid prototyping of low-cost, disposable lab-on-a-chip (LOC) devices.
• The process is suitable for applications outside of cleanroom environments.