Non-planar PDMS microfluidic channels and actuators: a review

Area of Science:

• Materials Science
• Microfluidics
• Additive Manufacturing

Background:

• Conventional microfabrication limits the creation of complex, non-planar microfluidic structures.
• Polydimethylsiloxane (PDMS) is a versatile material for microfluidic devices.
• There is a growing need for 3D microfluidic channels and actuators with intricate geometries.

Purpose of the Study:

• To review the state-of-the-art in manufacturing non-planar miniature channels and actuators from PDMS.
• To highlight advances in fabrication techniques, particularly those enabling geometries beyond conventional microfabrication.
• To evaluate fabrication methods based on geometric complexity, automation, and feature size.

Main Methods:

• Literature review of existing fabrication techniques for 3D PDMS structures.
• Categorization of fabrication methods based on themes and geometric complexity.
• Analysis of PDMS actuator properties including feature size, actuation stroke, and method.
• Consideration of additive manufacturing's impact on arbitrary 3D structure creation.

Main Results:

• Non-planar structures, including those with rounded or variable cross-sections and out-of-plane trajectories, are achievable.
• Additive manufacturing allows for the creation of arbitrary 3D structures down to approximately 100 μm.
• Fabrication methods are evaluated for their capability in producing complex geometries and their automation potential.

Conclusions:

• Recent advances, especially in additive manufacturing, significantly expand the possibilities for creating complex 3D microfluidic devices from PDMS.
• The review provides a framework for understanding and selecting appropriate fabrication methods for non-planar PDMS microstructures.
• Future work can leverage these advanced techniques for novel microfluidic applications and actuators.