Biocompatibility of Ar plasma-treated fluorinated ethylene propylene: Adhesion and viability of human keratinocytes.

Suitable surface modification of synthetic polymers is vital for improvement of cell adhesion to such materials. To that effect, reproducible modification methods such as argon plasma treatment are advantageous. We have previously described a significant improvement of cell adhesion and proliferation on Ar-plasma modified fluorinated ethylene propylene (FEP). In the experiments presented here, we sought to gain a closer insight into cell adhesion on modified FEP matrices by means of analysis of focal adhesions (FAs) as markers of adhesion. The length of FAs visualized by immunofluorescent labelling of talin 1 in human keratinocytes (HaCaT) cultured on selected Ar plasma modified matrices was greater at 24 h than at 72 h. The number of FAs per cell with FAs increased for some of the modified surfaces during the 72 h period and the percentage of cells with FAs mildly decreased. Furthermore, we analyzed the percentage of live HaCaT cells on the tested matrices by means of live/dead staining, with cells reaching almost 100% viability on modified FEP matrices. Altogether, Ar plasma modification positively affected viability and adhesion of HaCaT cells on FEP. Both these features may be related because formation of focal adhesions not only enables cell adhesion but also affects intracellular signaling. We also show that the assessment of suitable surface modification of biocompatible materials should be more complex than mere evaluation of viability or number of the cells on the surface.