Local ultraviolet laser irradiation for gradients on biocompatible polymer surfaces

Generation of supporting structures, which guide cell growth, is a challenging task in the field of tissue engineering. Cell guidance properties of a scaffold are important in the field of neuronal regeneration. Those guiding structures can provide guidance just by mechanical stimulus or by chemical stimuli like cell signaling molecules. For an enhanced guidance, chemical gradients are under investigation. With this study, we show that ultraviolet laser irradiation is a useful tool to activate polymer surfaces with a high temporal and spatial resolution. We demonstrated that poly(methyl methacrylate) (PMMA) and poly-?-caprolactone (PCL) can be locally activated and functionalized with amine groups that can be used for immobilization of arginine–glycine–aspartic acid (RGD) peptide. The immobilized RGD was detected by neuronal B35 cells. By defined pulse accumulation functionalization density on the surface can be varied for the generation of gradients. We demonstrated that PMMA and PCL have different process windows for functionalization. Although PMMA has a very small process window for activation, PCL allows the generation of stepwise functionalization. The presented technology can help to develop assays for the analysis of cell migration and neuronal regeneration due to flexible patterning easily realized by changing the irradiation parameters