Electrokinetic properties of commercial vascular grafts

The surface morphology and chemical composition (the presence or absence of surface functional groups) of commercial vascular grafts' surfaces are significant for their interaction abilities with components of polar liquids. This can also be assumed as correct for grafts-blood interactions. In this paper we studied the adsorption characteristics of different grafts' surfaces using an electrokinetic measurement technique. A comparative study was performed on woven, knitted polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) vascular grafts. Streaming potential measurements were used for the determination of zeta potential (ζ), which was studied as a function of electrolyte solutions' pH and surfactant concentration (using standard cationic surfactants i.e. N-CP-Cl, N-DP-Cl) in order to obtain information about critical charge reversal concentration (CRC). The analysed surface morphology and some physical properties were correlated with the electrokinetic properties of different grafts, and studied regarding their adsorption characteristics. The SEM images of grafts' surfaces show that woven PET has more densely packed and more-ordered structure than knitted PET. The PTFE surface exhibits a typical micro-porous structure for a tubular membrane. The strong dependence of zeta potential can be observed from the exposure time to the electrolyte solution. The ζ-pH functions (pH of electrolyte solution) show significant differences between different grafts. Small differences in molecular masses between both surfactants applied cause clear differences in the adsorption behaviours of the arterial grafts.