The quest for blood-compatible materials: Recent advances and future technologies

The development of blood-compatible materials represents a grand challenge in biomaterials science. Blood is a complex fluid containing many types of living cells, functional proteins, and other signaling molecules, which work together to protect the circulatory system from injury, pathogens, and foreign materials. Blood-contacting biomaterials include the components of cardiovascular implants (such as stents, shunts, and valves) and extracorporeal circuit components (such as tubing, membranes, and pumps). The engineered materials used in these applications are distinctly unlike the biological tissues that make up the cardiovascular system in their physical, chemical, and biological properties, leading to undesirable—and sometimes catastrophic—blood-material interactions. The pursuit of blood-compatible materials challenges nearly every aspect of materials design, including composition, mechanical properties, structure across multiple length scales, tribology, surface physical-chemistry, and biochemical functionalization. Materials have been designed to bind or reject specific blood proteins, interact favorably with specific cell types, or to interact with particular biochemical pathways in blood. This review summarizes the important blood-material interactions that regulate blood compatibility, organizes recent developments in this field from a materials perspective, and recommends areas for future research.