Modification of the biomaterial surface topography is a promising strategy to prevent bacterial adhesion and biofilm formation. In this study, we use direct laser interference patterning (DLIP) to modify polystyrene surface topography at sub-micrometer scale. The results revealed that three-dimensional micrometer structures have a profound impact on bacterial adhesion. Thus, line- and pillar-like patterns enhanced S. aureus adhesion, whereas complex lamella microtopography reduced S. aureus adhesion in static and continuous flow culture conditions. Interestingly, lamella-like textured surfaces retained the capacity to inhibit S. aureus adhesion both when the surface is coated with human serum proteins and when the material is implanted subcutaneously in a foreign-body associated infection model.

In this work, we describe a laser-assisted microstructuring technique called Direct Laser Interference Patterning to produce topographical cues for tumor cells in a one-step process. Line-like patterns with spatial periods ranging from 500 nm to 10 mu m are fabricated on polyimide (PI) films. The resulting structures exhibit a well-defined shape and quality even for patterns with small periodic distances. Subsequently, the behavior of mouse mammary adenocarcinoma cells over those structures is evaluated. The results show that cell growth is well aligned to the direction of the patterns (over 60% lying within 0 degrees to 15 degrees to either side of the surface lines) for all evaluated structure sizes. Moreover, cells grown on patterns with 500 nm spatial period are the most narrowly aligned (up to 80% found between 0 degrees and 15 degrees), showing the potential of the technique. The fabrication process of the PI patterns is supported by a mathematical model of the underlying photo-chemical ablation process

land. He has been award with the Fritz-grasenick prize 2007 and the Werner Köster prize 2006 for his work related with FiB-Tomography and Laser processing, respectively. After a postdoctoral stage at the georgia institute of Technology and the University of michigan (Alexander von Humboldt Fellowship), he joined the Fraunhofer iWS where he is currently the head of the Surface Functionalization group. The AuThorS This report introduces a recently developed method for the direct fabrication of 2D and 3D structures. The technique involves the modulation of the laser beam intensity by generating interference patterns. By using high power lasers it is possible to directly modify the material's surface obtaining micro-and submicrometer periodic arrays with controlled spatial modulation. Some examples of fabricated structures on metals, polymers as well as ta-C layers are discussed.

Periodic patterned surfaces do not merely provide unique properties, but act as intelligent surfaces capable of selectively influencing multiple functionalities. One of the most recent technologies allowing fabrication of periodic arrays within the micro- and submicrometer scales is Direct Laser Interference Patterning (DLIP). The method permits the direct treatment of the material's surface based on locally induced photothermal or photochemical processes. Furthermore, DLIP is particularly suited to fabricate periodic patterns on planar and non-planar surfaces offering a route to large-scale production. In this paper, the fabrication of spatially ordered structures on different materials such as polymers, metals and diamond like carbon films is discussed. Several application examples as fu nction of the processed material are introduced, including bio functional surfaces for cell guidance on polymers, wear resistant properties for structured diamond carbon like coatings and metals, as well as micro-patterned flexible polymers with controlled optical properties