PLASMA-INDUCED GRAFTED POLYMERIZATION OF ACRYLIC-ACID AND SUBSEQUENT GRAFTING OF COLLAGEN ONTO POLYMER FILM AS BIOMATERIALS

Polyacrylic acid (pAA) was introduced onto Ar-plasma treatment silicon e rubber (SR) membrane surfaces by plasma-induced grafted polymerizati on. Collagen (type III) was also linked with the carboxylic group of P AA grafted onto the SR surface via a carbodiimine agent to obtain a se condary structure of SR. The SR surface properties were characterized by ATR-FTIR, ESCA, contact angle, and SEM. The biocompatibility of the SR surface was evaluated by a culture of cornea epithelial (CE) cells . Subsequently, 75-450 mu g cm(-2) of pAA were obtained on the SR surf aces under different reactive conditions; 3-12 mu g cm(-2) of collagen were linked on modified surfaces of SR. Moreover, ATR-FTIR and ESCA w ere utilized to confirm the proceedings of these reactions. The hydrop hility of the modified SR was measured by a contact angle meter. The v alues of contact angle for SR grafted with pAA were approximately 45-5 0 degrees; a 50-55 degrees contact angle on pAA-g-SR to be further lin ked with collagen was subsequently obtained. Moreover, the influence o f surface properties toward migration, growth and attachment of CE cel ls on the modified surfaces was also examined. Here, untreated SR was used as a control. Experimental results indicated that the number of C E cells attached onto the controlled SR was negligible. The attach men t of cells onto pAA-grafted surfaces was clearly observed and peusopod a occurred; however, cell growth was depressed. This depression may ha ve been caused by the acid environ ment of the pAA-grafted membrane. N evertheless, both cell attachment and growth onto collagen-linked surf aces were significant. In addition, the morphology of the cells attach ed onto this surface was considered normal for primary cells. Collagen introduced on the SR surface was not denatured, i.e. the natural prop erties of collagen were maintained. The results obtained in this study will hopefully lead to the successful development of modified SR for clinical applications. (C) 1996 Elsevier Science Limited