Surface characteristics including surface wettability, potential, energy, topography, and reactivity govern the hemo and cell compatibility of artificial grafts (Figure ). Superhydrophobic surfaces characterized by low water sliding angles (<10) and high-water contact angles (>150) reveal reduced protein adsorption and less blood-material interfacial contact. Surface topography including wrinkles, wells, pillars, and/or other structural formations can modulate cell and protein adhesion and attenuate thrombosis by altering the surface area and energy. Similarly, surface charge and chemical reactivity may alter the hemocompatibility by modulating the interaction of surface groups and blood species at the blood-material interface. Chemical structures such as sulfonic groups can reduce protein adsorption and contact activation with blood, whereas carboxyl groups tend to heighten platelet activation and thrombin generation. The surface energy, surface charge, and chemical composition of materials act in concert to determine the likelihood of thrombosis and calcification. Below is a review of current functional modification strategies that have been applied to blood-contacting materials.