Biocompatibility evaluation of ePTFE membrane modified with PEG in atmospheric pressure glow discharge

ePTFE membranes were modified by poly(ethylene glycol) having a molecular weight of 600 (PEG‐600) in atmospheric pressure glow discharge (APG) plasma treatment. ePTFE membranes were immersed in 1%, 3%, or 5% (w/v) PEG‐600 in dehydrated ethanol. PEG‐600‐penetrated ePTFE membranes were dried in a vacuum to immediately remove ethanol, then treated with APG at 20 kHz and 60–70 W for 15 min and thoroughly washed with ethanol and water. PEG‐600‐modified ePTFE membranes were analyzed using contact angle measurement, Fourier transform infrared attenuated total reflectance (FTIR‐ATR), and scanning electron microscopy (SEM). ePTFE membrane contact angles were reduced after PEG‐600 plasma treatment. FTIR‐ATR spectra showed an absorption band due to a PEG hydroxyl group (‐OH). SEM showed that ePTFE fiber surfaces were uniformly immobilized with PEG‐600 and retained their porous structure. A general biological evaluation of the PEG‐modified ePTFE membranes showed no cytotoxicity on CHO‐K1 cell lines and no hemolytic action. Albumin adsorption on the PEG‐modified ePTFE membranes increased with increasing PEG‐600 deposited on ePTFE membranes. Fibrinogen adsorption decreased with increasing PEG‐600 deposited on ePTFE membranes. γ‐Globulin adsorption did not change before or after PEG plasma modification. 1% and 3% PEG‐600 plasma‐treated ePTFE only slightly increased platelet adhesion, but adhering platelets evidenced no pseudopod formation. 5% PEG‐600‐modified ePTFE showed relatively large numbers of platelet adhesion. We concluded that 3% PEG‐600‐modified ePTFE membrane had the best physical properties and biological compatibility, indicating 3% PEG‐600‐modified ePTFE membranes exhibit the potential for blood filter application. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 502–509, 2002; DOI 10.1002/jbm.1294