Laser direct-write for fabrication of three-dimensional paper-based devices

Area of Science:

• Microfluidics
• Materials Science
• Analytical Chemistry

Background:

• Paper-based microfluidic devices offer low-cost platforms for diagnostics.
• Fabricating complex 3D structures in paper typically requires multi-step assembly.
• Existing methods are often time-consuming and not scalable.

Purpose of the Study:

• To introduce a laser-based direct-write (LDW) technique for fabricating 3D paper microfluidic devices.
• To demonstrate control over hydrophobic barrier depth for creating 3D flow paths.
• To enable multi-step analytical assays using a simplified 3D protocol.

Main Methods:

• Utilizing laser-induced photopolymerization within a paper substrate.
• Adjusting laser power and scan speed to control hydrophobic barrier depths.
• Integrating patterned layers to form 3D flow paths and device structures.

Main Results:

• Successfully fabricated 3D structures and flow paths within paper.
• Demonstrated depth-variable hydrophobic barrier patterning.
• Achieved stacking, sealing, and assembly of multi-layer devices, including 3D devices.
• Showcased formation of 3D flow paths via a single laser-writing process.

Conclusions:

• The LDW technique offers a significant improvement over traditional multi-step assembly methods.
• This approach is suitable for cheap, rapid, and large-scale fabrication of 3D paper-based microfluidic devices.
• Enables the implementation of complex, multi-step analytical assays on paper platforms.