FIGURE 2.

Increasing the SC3 concentration and incubation time promotes the transition of SC3 to the β-sheet state at the water-PTFE interface. This is indicated by a low WCA after treating the coated PTFE with Tween 20 at pH 7. WCAs were measured on PTFE sheets that had been incubated with 5, 50, 100, and 300 μg ml⁻¹ SC3 at pH 7. This was followed by washing with water (5 W, 50 W, 100 W, and 300 W) or with 0.1% Tween 20 at pH 7 (5 T, 50 T, 100 T, and 300 T). Coating was performed for 16 h (white bars), 3 h (gray bars), or 15 min (black bars). Uncoated PTFE has a WCA of 110 ± 2°, whereas PTFE coated with SC3 in the β-sheet state has a WCA of 48 ± 10° (7). Deg., degrees.