Blood-on-chips: flow through complex geometries

Abstract

Blood is a complex body fluid, composed of cells and plasma, which holds a massive amount of information about several physiological and pathologic events happening throughout the body. Hence, blood sampling and analysis are used extensively in traditional clinical laboratories for the diagnosis of several diseases. Since the inception of microfluidics, there has been a growing interest, by both microfluidic and biomedical communities, to develop blood-on-chip devices as an alternative tool for the diagnosis of major diseases, such as cancer and cardiovascular diseases. Therefore, it is essential to understand the blood flow behaviour involved in this kind of microfluidic channels in order to design reliable blood-on-a-chip devices able to efficiently treat and diagnose a variety of diseases. The present experimental study shows the effect of micro-scale contractions and expansions, such as those found in an artificial stenosis, on the blood flow and cell behaviour. The micro-channels were fabricated in PDMS using softlithography and the experiments were carried out by using dextran 40 containing different fractions of human erythrocytes. The in vitro blood flow was measured by means of a high-speed video microscopy system composed with an inverted microscope, a high-speed camera and a thermo plate to control the surrounding temperature.