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 technologies. Unlike existing methods that require complex fabrication and expensive materials, our approach uses a CO2 laser cutter to fabricate acrylic layers bonded with pressure-sensitive adhesives, making it cost-effective and simple. Operating via gravity sedimentation, the device captures blood cells in multiple trenches and processes 1 mL of whole blood—significantly more than previous sedimentation devices. To prevent bubble formation, we incorporated a hydrophilic surface at the trench bottoms, ensuring reliable PRP separation. We analyzed three trench geometries to optimize plasma yield and quality. Our device processes blood in 45 minutes, yielding ~300 µL of plasma with at least a 2-fold platelet concentration increase. Red and white blood cell removal purities are 98% and 96%, respectively. Flow simulations optimized shear rates to improve sedimentation. Only 8.2% of the total platelets were activated, compared to 31% in the centrifugation method. This combination of simplicity, cost-efficiency, and effective platelet preservation enables a low-cost method for obtaining high-quality PRP for clinical research and therapy.