Microchannel with Stacked Microbeads for Separation of Plasma from Whole Blood

Abstract A microfluidic device integrated with a microchannel stacked by two kinds of microbeads with different sizes and a capillary microchannel array was designed and fabricated. When whole blood sample flowed through these channels, blood cells were filtered and adsorbed by the stacked microbeads, and plasma could be separated rapidly. The microbeads were introduced into the channel by negative pressure and thus stacked compactly. Protein blocking solution was used to improve the hydrophilicity of the bead surface. Then the microchip was dried and cooled before 20 μL of blood was dropped in the inlet. Driven by capillary force, the blood proceeded in the channel. The influences of microbeads with different sizes and a locally widened microchannel were investigated. Experimental results showed that when microbeads with a diameter of 10 μm were filled in the locally widened microchannel, the separation rate of plasma was the fastest. The collection rate of plasma could reach up to 0.16 μL min −1 in this case, which could meet the requirement of most clinical applications. On the chip device, collected plasma was used to carry out the agglutination test, and the blood group could be determined quickly, which verified the usefulness of this method.