Regulating Blood Cell Lateral Migration for High Performance Platelet-Rich Plasma Separation

Platelet-rich plasma (PRP) has broad therapeutic potential, yet current separation methods remain challenged by the trade-off between platelet (PLT) concentration, purity, and activation status. Here, we develop a microfluidic strategy for PRP separation by integrating lateral migration regulation with gravitational settling of blood cells. We demonstrate that microchannel architecture modifies the secondary-flow structure within the settling chamber, thereby regulating the lateral migration of blood cells. Compared with a discrete settling chamber, a continuous settling chamber provides a longer settling path, facilitating PLT enrichment and blood cell separation. Simulations of the microchannel structural unit demonstrated preferential settling of WBCs and RBCs, while PLTs remained largely suspended. Across the tested operating conditions, the PRP chip achieved a maximum PLT enrichment ratio of 4.6 and a maximum purity of 94%. Compared with conventional centrifugation, PRP produced by the chip exhibited lower platelet activation, as evidenced by a lower CD62P-positive platelet fraction and lower platelet-activating factor concentrations. Comprehensive evaluation of PLT activation and PRP composition identified a Reynolds number range of 50−100 as optimal for the PRP chip.