Detection-free high-throughput cell sorting using fixed-position optical tweezers

Optical tweezers-based sorting is a promising technique for sorting cells with minimal damage, offering a gentle, non-contact radiation force to precisely manipulate cells into a collection channel. However, existing optical tweezers-based sorting systems heavily rely on detection technologies to classify cell types and require continuous repositioning the optical tweezers to steer cells toward the collection channel, which limits throughput and increases system complexity. In this work, we present a detection-free, high-throughput cell sorting method using fixed-position optical tweezers. Specifically, we designed a microfluidic chip featuring an arc-shaped protrusion, allowing the fixed-position optical tweezers to efficiently direct target cells into the collection channel through the combined influence of hydrodynamic forces and optical forces. This approach markedly enhances throughput, reaching a theoretical throughput of 10 cells/s, while simultaneously reducing system complexity and cost. The performance of the system was validated by sorting particles of varying sizes with a purity of 98.2 % and by separating cancer cells from erythrocytes with a purity of 95.5 %. Meanwhile, the system maintains high cell viability, making it well-suited for applications in clinical diagnostics, drug screening, and single-cell genomics.