Blood cells sorting using cotton threads

Abstract

Microfluidics systems have been developed for pretreatment of whole blood in last decades. Blood pretreatment or blood processing includes blood cell and plasma separation, white blood cell lysis and DNA purification, to name a few. In this project our focus is on blood cells sorting. Various methods have been demonstrated in literature for blood cell sorting and separation as one essential step of blood sample pretreatment in both the macro and micro scale. In this study we proposed cotton threads as a matrix for fabrication of cell sorting systems. this kind of thread used in this study is inexpensive and fabricated microfluidic device is low volume and easy to use particularly appropriate for the developing world or remote areas, because of their relatively low fabrication costs .threads provide wicking channel for liquid via capillary forces without any external forces as a pump. The use of threads for cell sorting is based on liquid wicking along the gapes inside the threads which can be manipulated by twisting thread. This means more twisting in the same direction of real twist of thread make the gaps smaller which bigger cells cannot pass them and trapped in the channel results their separation from smaller cells. Fabricated device in this study has 3 different zones through the inlet to the outlet which each zone has a different TPI (Twists per Inch) means different sizes of gapes. Blood used to test the ability of fabricated device to sort different size of cells and the result showed efficient separation of red blood cells, white blood cells and plasma. Based on these results threads cab be consider as a proper material in microfluidic devices to sort different cells by their size.