Quantitative measurement of C3 activation at polymer surfaces.

Activation of C3 by nylon 6.6 and polymethyl methacrylate (PMMA) polymers in whole canine serum was investigated using Laurell electroimmunoassay and antigen-antibody crossed immunoelectrophoresis (XAA). Canine sera were utilized because most artificial blood contact materials used in prosthetic devices are tested in dogs. The measurements were made possible by converting the polymers to microparticles, increasing the available surface area to approximately 200,000 sq cm/g. Both polymers activated C3 within a few minutes of serum contact at 39’C. the canine biologic temperature, after which no further development was seen. Nylon activation, studied in detail, increased with increasing surface area up to a saturation level of about 20% conversion reached at approximately 350 sq cm/mI polymer surface/serum