Label-free Microfluidic Sensing by Detection of Interaction-triggered Change in Blood Flow Characteristics

Abstract Microfluidic devices exploit combined physical, chemical and biological phenomena that could be unique in the sub-millimeter dimensions. The blood is a non-Newtonian fluid, containing particulate and soluble elements, which penetrates the whole body carrying a wealth of biomedical information. The design of microfluidic devices capable of extracting immediately this information is the current goal of development Point-of-Care (POC) medical devices. We examined the characteristics of blood flow in specially designed microfluidic devices having different geometric structure and material composition with the aim of defining suitable conditions for sensitive detection of changes in the interactions between particulate elements of the blood and the adequately modified surfaces of the microfluidic system. As a model experiment we demonstrated the fast analysis of the AB0 blood group system, applying respective antibody reagents and capillary blood samples with different blood groups. We showed that by tuning the hydrophilicity of the surface and capillary dimensions of the microfluidic system it is possible to detect precisely the red blood cell binding to the capillary walls by monitoring the flow rate characteristics in an autonomous microfluidic system. Our proof-of-concept results point to a novel direction in blood analysis in autonomous microfluidic systems and also provide the basis for the construction of a simple quantitative device for blood group determination