bloodcontacting

Blood-contacting refers to materials, surfaces, or devices that come into contact with circulating blood. In medical contexts, such surfaces include catheters, vascular grafts, heart valves, stents, dialysis circuits, and extracorporeal circulation components.

The primary concern is hemocompatibility—the ability to perform without causing adverse reactions such as thrombosis, inflammation, or hemolysis. Protein adsorption from plasma, described by the Vroman effect, often mediates subsequent cellular responses including platelet adhesion and activation, coagulation, and immune reactions. The extent and consequences of these interactions depend on factors such as chemical composition, surface charge, roughness, hydrophilicity, and the duration of contact, as well as whether flow is static or dynamic.

Evaluation uses in vitro tests such as platelet adhesion and activation assays, thrombin generation, clotting time measurements, and complement activation; dynamic blood loop studies and in vivo animal models are also employed. Testing is guided by international standards and regulatory frameworks for biocompatibility, including general device evaluation and specific hemocompatibility considerations.

Strategies to improve hemocompatibility include surface modification with heparin or other anticoagulant coatings, hydrophilic or zwitterionic surface coatings, nitric oxide releasing materials, phosphorylcholine-containing coatings, and other biopassive or biomimetic approaches. In some cases, devices integrate drug-eluting or bioactive surfaces to control thrombosis and inflammation. Regulatory and clinical considerations emphasize risk assessment for thrombotic and inflammatory complications, particularly for long-term or high-shear applications. Understanding blood-contacting interactions is a multidisciplinary area at the intersection of materials science, biology, and medicine.