The use of membranes or surfaces made by proteic polymers allows unexpected contributions to the technology of extracorporeal prostheses. Our method of membrane and surface production is based on polymerization of proteins with reticulating agents leading to insoluble and irreversible tri-dimensional polyproteic structures. Various proteins such as albumin, hemoglobin, lysozyme, or fibrinogen can be used. According to the operational modes, various structures such as membranes or gels can be obtained. Incorporation of enzymes confers particular catalytic properties on the structure. Despite recent developments, membrane oxygenators are subject to two quite constraining limitations: The device and especially the gas diffusion membranes, as well as the junctions and constrictions of the circuits, modify the blood constituents and lead to progressive denaturation of fibrinogen, resulting in a layer of fibrin. In addition, ...