Human monocyte adhesion and activation on crystalline polymers with different morphology and wettability in vitro

This study evaluated the effects of crystalline polyamide (Nylon-66), poly( ethylene-co-vinyl alcohol) (PEVA), and poly(vinylidene fluoride) (PVDF) pol ymers with nonporous and porous morphologies on the ability of monocytes to adhere and subsequently activate to produce IL-1 beta, IL-6, and tumor nec rosis factor alpha. The results indicated monocyte adhesion and activation on a material might differ to a great extent, depending on the surface morp hology and wettability. As the polymer wettability increases, the ability o f monocytes to adhere increases but the ability to produce cytokines decrea ses. Similarly, these polymers, when prepared with porous surfaces, enhance monocyte adhesion but suppress monocyte release of cytokines. Therefore, t he hydrophobic PVDF with a nonporous surface stimulates the most activity i n adherent monocytes but shows the greatest inhibition of monocyte adhesion when compared with all of the other membranes. In contrast, the hydrophili c Nylon-66, which has a porous surface, is a relatively better substrate fu r this work. Therefore, monocyte behavior on a biomaterial may be influence d by a specific surface property. Based on this result, we propose that mon ocyte adhesion is regulated by a different mechanism than monocyte activati on. Consequently, the generation of cytokines by monocytes is not proportio nal to the number of cells adherent to the surface. (C) 2000 John Wiley & S ons, Inc.