Dimensions and capillary effects of microfluidic channel for blood plasma separation

This paper presents a cross-flow microchannel network for separation blood plasma on a microfluidic chip. The whole blood could be introduced into the microchannel via the effects of capillary forces alone, i.e., there was no need for any external driving force. A microfluidic chip for plasma separation including a cross-flow microchannel consisting of a straight main microchannel and a filtration microchannel has been proposed. The microfluidic chip used for plasma separation is fabricated from a single polydimethylsiloxane (PDMS) mold and sealed with an etched glass substrate. Since filtration microchannel depth is less than 2 μm, plasma can be extracted from whole blood. The merits of this design are its simple structure, high separation efficiency and without any external driving force. The experimental results show that this design can extract at least 0.02 μl of plasma from whole blood within 25 s and with a residual cell concentration of less than 0.07 % in the purified plasma.