Femtosecond Laser‐Driven Fabrication of a Polymeric Lab‐on‐a‐Chip for Efficient Size‐Based Particle Sorting in a Spiral Microchannel

The development of polymer-based Lab-on-a-Chip devices is increasingly benefiting from advanced prototyping techniques that provide exceptional precision and adaptability. This study introduces an innovative fabrication approach that integrates simulations, femtosecond laser processing, and experimental validation to optimize microfluidic channel design. The proposed method relies uniquely on scanning speed as the laser control parameter, a strategy not previously reported in the literature. This approach ensures reproducibility, rapid processing, and excellent precision, making it a highly efficient and scalable solution for Lab-on-a-Chip production. Specifically, we present the fabrication of a microfluidic device with a trapezoidal cross-section, which has demonstrated outstanding efficiency in its intended application. The device is fabricated using polymethylmethacrylate and exploits inertial effects in a spiral microchannel with asymmetric outlets to achieve size-based particle separation. The device successfully separates 20 µm and partially 6 µm particles, mimicking circulating tumor cells and red blood cells respectively, in agreement with the simulation predictions. This simulation-driven design approach highlights critical insights into the laser-based fabrication process, demonstrating it being an efficient method for producing functional devices. With its low-cost materials, customizable design, and strong potential for biological applications, this fabrication technique holds significant promise for commercialization and point-of-care diagnostics.