3D-Printed Closed-Channel Spiral Inertial Microfluidic Device for Size-Based Particle Separation

Area of Science:

• Microfluidics
• Particle Separation
• 3D Printing

Background:

• Spiral inertial microfluidic devices offer high-throughput, size-based particle separation.
• Translating polydimethylsiloxane (PDMS)-optimized designs to 3D-printed channels faces printability and post-print clearing challenges.
• Previous PDMS studies achieved high separation with a 400×120µm spiral.

Purpose of the Study:

• To develop a faster, cost-effective manufacturing approach for spiral inertial microfluidic devices using 3D printing.
• To re-optimize the spiral geometry for manufacturability constraints in a fully 3D-printed, closed-channel device.
• To retain high particle separation performance in a monolithic 3D-printed format.

Main Methods:

• Re-optimized spiral geometry for 3D printing, focusing on manufacturability and channel clearing.
• Utilized particle-tracking simulations to optimize spiral development length for particle collection.
• Experimentally validated the performance of the 8-turn, 800×240µm 3D-printed device using fluorescent polystyrene particles.

Main Results:

• Successfully printed and cleared enclosed channels with cross-sections of 800×240µm and 1200×360µm.
• An 8-turn spiral design achieved 100% large-particle collection (12-24µm) and reduced small-particle crossover.
• Experimental validation showed 84% collection efficiency and 92% purity for 18µm target particles.

Conclusions:

• Spiral inertial separation is feasible in monolithic 3D-printed devices.
• Design re-optimization around the smallest reliably clearable enclosed cross-section and sufficient spiral length is crucial.
• This approach enables faster and more cost-effective production of high-performance microfluidic separation devices.