Optimization of Injection-Molded Thermoplastic Microfluidic Chip Design with Numerical Modeling and Two-Photon Polymerization 3D Printing

Abstract Precise microfluidic geometries are critical for particle dynamics studies but challenging to fabricate repeatably and rigidly. This study aims to experimentally validate computational fluid dynamics predictions of particle trajectories in cross-slot junctions, overcoming previous manufacturing limitations. We developed a novel fabrication process combining precisely bonded injection-molded chips with integrated two-photon polymerization 3D-printed junction geometries. Using this approach, experimental measurements of microsphere trajectories via the Cytovale system successfully validated predictions, confirming the influence of stenosis and outlet widths. This work establishes a robust methodology for optimizing microfluidic designs by synergizing advanced manufacturing and simulation, enabling precise experimental investigations.