Direct laser writing-enabled 3D printing strategies for microfluidic applications

Area of Science:

• Additive Manufacturing
• Microfluidics
• Lab on a Chip

Background:

• Additive manufacturing, particularly direct laser writing (DLW) using two-photon polymerization (2PP), offers high precision for microfluidic device fabrication.
• DLW excels at creating intricate structures at the 100 nm scale but struggles with larger macro-to-micro fluidic interfaces.
• Existing microfluidic applications include organ-on-a-chip, drug delivery, particle processing, and soft microrobotics.

Purpose of the Study:

• To review and discuss prominent strategies for fabricating macro-to-micro fluidic interfaces using DLW.
• To highlight how these strategies overcome the limitations of DLW's small voxel size for microfluidic systems.
• To explore the future potential of DLW in Lab on a Chip applications with advanced printer capabilities.

Main Methods:

• Discussion of four key strategies developed to integrate macro-scale fluidic ports with microfluidic devices fabricated by DLW.
• Analysis of the challenges posed by the small voxel size of DLW in creating functional fluidic interfaces.
• Consideration of emerging DLW technologies and their impact on microfluidic fabrication.

Main Results:

• Four distinct approaches have been identified and analyzed for creating macro-to-micro interfaces essential for DLW-based microfluidics.
• These strategies effectively bridge the gap between the high-resolution capabilities of DLW and the macroscopic requirements of fluid handling.
• The review provides a comprehensive overview of current solutions for a critical fabrication challenge.

Conclusions:

• The successful integration of macro-to-micro interfaces is crucial for realizing the full potential of DLW in microfluidics.
• Advancements in DLW technology, including dynamic voxel tuning, promise to further expand its utility in Lab on a Chip applications.
• Continued development of fabrication strategies will drive innovation in complex microfluidic systems.