A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures

We optimized a micro-fluidic set-up to study the interaction of whole blood with nano-structured polymer surfaces under flow conditions. Micro-fluidic chips were coated with polymethylmethacrylate films and structured by polymer demixing. Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm. Whole blood flow rate through the micro-fluidic channels, platelet adhesion and von Willebrand factor and fibrinogen adsorption onto the structured polymer films were investigated. Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size. Adhesion and spreading of platelets from whole blood and von Willebrand factor adsorption from platelet poor plasma were enhanced on the structured surfaces with larger feature, while fibrinogen adsorption followed the opposite trend.We investigated whole blood behaviour and plasma protein adsorption on nano-structured polymer materials under flow conditions using a micro-fluidic set-up. We speculate that surface nano-topography of polymer films influences primarily plasma protein adsorption, which results in the control of platelet adhesion and thrombus formation.Blood compatibility of materials is one of the major issues of medical engineering. Devices for cardiovascular applications are widely used but still do not exhibit optimal performances and must be often combined with anticoagulation drugs, with important implications for patient health and therapy costs [1]. The techniques available to evaluate the blood compatibility of materials to date are still limited, in spite of the heavy demand for methods allowing the quantitative and accurate characterization of the polymers used in the construction of cardiovascular devices [2].The difficulties encountered in characterising the interaction of blood with materials are due principally to the complexity of the phenomena involved. The adsorption and subsequent conformational changes of proteins