A microfluidic device for passive separation of platelet-rich plasma from whole blood

We present a microfluidic device for separating platelet-rich plasma (PRP) from whole blood, addressing key limitations in current sedimentation-based technologies. Unlike existing methods that rely on a single sedimentation trench-limiting plasma yield and processing speed-our device incorporates a novel multi-trench design, allowing the processing of 1 mL of whole blood in 40 minutes, yielding ∼250 μL of PRP with at least a 2-fold increase in platelet concentration. The device is fabricated using a CO₂ laser cutter on acrylic layers and bonded with a pressure-sensitive adhesives, offering a cost-effective and simple alternative to more complex manufacturing processes. To ensure reliable PRP separation and minimize bubble formation, we applied a hydrophilic coating at the trench bottoms. We analyzed three trench geometries to optimize PRP yield and quality. Flow simulations optimized shear rates to improve sedimentation. Our approach effectively removes red and white blood cells with purities of 98% and 96%, respectively, only 8.2% of the total platelets were activated post-processing, compared to 31% with conventional centrifugation. This combination of a novel multi-trench layout, simplicity, cost-efficiency, and effective platelet preservation enables a low-cost device for obtaining high-quality PRP for clinical research and therapy.