Laser interference lithography micropatterning of polymer surface for cell adhesion

Cell-surface interactions are fundamental aspects to understand the role of surface chemistry and topography of biomaterials. If cells differ in their response to topographic variations, this phenomenon may be exploited to regulate cell functions and to design implant materials. Cell responses to surface topography, especially the orientation and differentiation induced by surface micropatterns, are called contact guidance. In this work laser interference lithography was introduced to prepare periodic linear and point micropatterns for study of contact guidance of mammalian cells. This process provides a straightforward micropatterning technique based on selective laser ablation of polymers utilizing the periodic energy distribution of two or more beam interference patterns. The ablation mechanisms of polymers were studied with time of flight mass spectroscopy, X-ray photoelectron spectroscopy, and by using thin polymer solution followed by spectroscopic analysis and molecular weight measurement. The micropatterning process was optimised with respect to polymer properties, laser fluence and pulse number. The micropatterns were characterized by atomic force microscopy, scanning electron microscopy and white light interferometry.