Adhesion of L1210 cells to modified styrene copolymer surfaces in the presence of serum

Abstract

The static adhesion of living L1210 cells (in serum-containing medium) to the surface of (styrene/methylmethacrylate) copolymers differing in styrene content (from 5% to 50% of styrene units) was investigated. The examination of wettability of the copolymer surfaces showed that the contact angle of water on the hydrophobic surfaces is an increasing linear function of styrene content in the copolymer. Cell adhesion to the unwettable surfaces is low (within 2-4%). A novel method of modification of the styrene copolymer surfaces was used to render these surfaces suitable for cell attachment. The modification consists of sulfonation of the surfaces with sulfur trioxide at the gas/solid interface. The contact angle of sulfonated copolymer surfaces is a decreasing linear function of styrene content in the copolymer. The contact angle decreases due to the increased number of highly hydrophilic sulfonic groups bonded to styrene. By acetylation of the sulfonated surfaces it was shown that cell adhesion to acetylated surfaces is not diminished and is at the same level as cell adhesion to sulfonated copolymer surfaces. Thus, it can be concluded that sulfonation of copolymer surfaces does not form hydroxyl groups. Cell adhesion to substrata of high wettability stabilizes after 30s. The relative number of cells adhering to the sulfonated copolymer surfaces is a decreasing linear function of the contact angle. For the copolymer surfaces containing 50% of styrene units the contact angle decreases sevenfold, due to sulfonation, and the number of adhering cells increases 40-fold. The results obtained show that for cell-substratum adhesive interaction the presence of sulfonic groups at the substratum surface is important.