Whole blood spontaneous capillary flow in narrow V-groove microchannels

Open microfluidic systems, i.e. microflows with a free surface, are finding increasing use in the fields of biotechnology, biology and medicine, especially in the domain of point-of-care (POC) and home care systems. In such systems the fluid is moved by capillarity. It is now known that the use of microgrooves enhances the capillary effect. In this work the spontaneous capillary flow of fluids inside a narrow V-groove microchannel is investigated. In the first part of the study, the condition for spontaneous capillary flow in a V-groove geometry is determined. This is followed by a theoretical analysis of the flow dynamics. Finally, theoretical predictions of flow are compared to corresponding experimental data. It is shown that large fluid velocities can be obtained, even with viscous fluids such as whole blood. This property could be used to design POC systems for the monitoring of blood.