How fibroblasts respond to different biomaterials: comparative adhesion and proliferation studies

Biomaterials from different categories have been thoroughly investi- gated regarding their use in scaffolds for skin tissue engineering. How- ever, a direct comparison between polymers of different natures is seldom reported. Therefore, we decided to study the performance of three different polymers in promoting the adhesion and proliferation of fibroblasts grown on electrospun nanofibers. A polyester (polycaprolac- tone), a polysaccharide (chitosan) and a protein (gelatin from cold water fish skin) were used. Characterization of the electrospun mats was conducted by SEM, porosity evaluation and mechanical testing. In vitro tests were made by culturing 3T3 fibroblasts up to 7 days. Cell viability was determined using the WST-8 assay. Morphology was observed using SEM. Cells were stained for confocal microscopy obser- vation of the nuclei and cytoskeleton. Gelatin scaffolds had the best overall performance: cells attached and spread well, their number equalled that of the controls and they exhibited the expected morphol- ogy with polygonal shapes. Cells then proliferated until confluence. Adhesion to chitosan nanofibers was less efficient: cell number decreased significantly but then initial seeding density was reached by day 3. In addition, we observed that cells tended to grow in clumps. PCL showed to be the least suitable substrate in terms of cell adhesion: a high number of cells died; however, those that attached proliferated and the initial seeding density was reached by day 6.