It has become necessary to develop a new filtering type of artificial kidney for the development of an artificial kidney which is portable or capable of placing internally.
As a result of study of a filtering membrane isolating plasma from blood, an expanded polytetrafluoroethylene (EPTFE) membrane treated with alcohol is found excellent for blood filtering membrane at present.
The EPTFE membrane (thickness 11.5 micron, pore size 0.7 micron) used for the experiment is excellent in antithrombogenicity and in mechanical strength, and is also good for the use of blood filtration.
Antithrombogenicity improves at the surface with negative electrical charge—the electret state. However, an EPTFE membrane treated with alcohol, in order to pass water, almost loses the above-mentioned effect.