Design and fabrication of blood plasma separation PMMA chip using capillary phenomenon

In this study, a microdevice driven by capillary action has been developed for the high-throughput on-chip separation of plasma from a drop of blood. The microdevice is composed of an array of 2 µm deep and 2 µm wide PMMA (polymethylmethacrylate) channels. This PMMA microfluidic device is fabricated by hot embossing and thermal bonding from a Si master mold. The PMMA device was modified using oxygen plasma and poly-L-lysine in order to obtain a hydrophilic surface. After injection of a blood sample, the plasma flowed rapidly and arrived at the outlet within 3 min, demonstrating a 100% separation ratio of red blood cells. In addition, no hemolysis was observed. Because the proposed blood separation device is driven solely by capillary action, its passive mode of operation eliminates the need for microfluidic pumps or any other additional power supply. It is therefore possible to miniaturize it as an entire system.