Abstract

3D Printed Droplet and Inertial Microfluidics

Vivek Rajasenan, PhD Candidate, UCLA

Resin 3D printing is replacing conventional techniques in microfluidics manufacturing due to its prototyping speed and channel-shaping capabilities. While simple in nature, this manufacturing approach is typically limited by channel resolution (>100 microns), caused by large penetration depths in resins resulting in partially polymerized resins in embedded microchannels. Techniques aiming to address this challenge, such as resin absorbers and optical tuning, constrain material properties or require complex, custom-built printers, posing obstacles that frequently impede accessibility. Leveraging the remnant reactive groups in the resin following low-cost LCD-based SLA printing, we introduce a simple and scalable compression bonding method to create high-resolution, high-strength, and transparent microfluidic devices capable of withstanding pressures greater than 280 psi. We demonstrate shear-free step emulsifiers with sub-100-micron channels that can produce very precise droplets (<5% CV) and particles at scale. We also demonstrate a rigid inertial microfluidic device capable of focusing microparticles into single streams.