Endothelial cell formation of focal adhesions on hydrophilic plasma polymers

Endothelial cell (EC) formation and distribution of both actin stress fiber s and focal contacts on hydrophilic plasma polymers derived from gamma -but yrolactone (GBL) and n-vinylpyrrolidone (NVP) were examined to determine th eir ability to support endothelial cell growth in comparison to fibronectin . One hour after seeding, cells adhered and spread moderately on fibronecti n with the development of defined actin stress fibers and focal adhesions c ompared to NVP and GBL, on which the cells were spread with poorly develope d stress fibers and a perinuclear localization of vinculin. At 3 h, cells c ontinue to spread more on fibronectin and NVP than GBL, and the cells on fi bronectin had well-defined stress fibers terminating with sharp spikes of v inculin, typical of focal adhesions. At this time point, paxillin, a signal ing component of focal adhesion complex, was predominantly localized at the focal contacts for well-spread EC on fibronectin and NVP, whereas it was a lmost entirely concentrated in the perinuclear region of less-spread cells on GBL. However, by 24h, cells were much more spread on all three surfaces with defined stress fibers and focal contacts although EC expression of vin culin and paxillin was moderate on GBL compared to fibronectin and NVP. The se results suggest that EC can form cytoskeletal structures necessary for c ell survival on plasma polymers, especially on more hydrophilic NVP, which could be exploited as interface material for seeding endothelial cells. (C) 2001 Elsevier Science Ltd. All rights reserved.