Recent studies have shown that polymeric scaffolds as a synthetic extracellular matrix (ECM) are essential for regenerating tissues or organs in tissue engineering approaches. Controlling the surface functionality of polymer scaffolds is critical in regulation of cellular responses to the scaffolds during tissue formation. However, the stress response of cells to polymer scaffolds with different surface characteristics is not yet clear. We investigated the expression of heat shock protein (HSP) and Bcl-2 in fibroblasts cultured on electrospun nanofiber matrices with different surface characteristics. The hydrophilicity and chemical composition of electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers was regulated by plasma treatment in the presence of ammonia gas. We found that expression levels of HSP and Bcl-2 in fibroblasts were strongly dependent on the surface hydrophilicity and concentration of nitrogen-containing functional groups on the nanofiber matrices. The controlled hydrophilicity and surface chemical composition of nanofiber matrices enhanced adhesion and spreading of cells on the matrices, resulting in reduction of cellular stress. This approach to controlling the surface properties and regulating expression of a stress gene could be useful in the design of synthetic ECMs for many tissue engineering applications.
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