Surface micro and nanostructuring of three-dimensional components of micro medical devices

Abstract

Surface structuring of medical implants has been shown to reduce the rejection rate of medical devices inserted inside living tissue. Several studies have shown that by texturing the surface of medical implants at micro/nanoscale it is possible to foster cell adhesion. The surface texturing of medical devices poses many challenges in terms of cost and time when the nano texturing process is performed directly on the part surface. A viable solution for mass production of polymer based surface enhanced medical devices is achieved via injection molding. However, nano structuring of micro injection molding molds, requires techniques enabling processing of complex surfaces, small curvature radii and with high aspect ratios. Furthermore the accessibility of all surfaces to be structured and the processing time are the main concerns and limiting factors on the selection of the structures dimensions and geometries. In this work, two different process chains are analyzed for the nano structuring of a bone micro plug. The first method relies on a chemical deposition process in order to produce a semi random structure on the entire mold surface of the medical component. The characteristic size of the structures is controlled by acting on the deposition parameters. The second process, relies on laser structuring of the mold components by producing Laser-Induced Periodic Surface Structures (LIPSS).The two process chains are compared and an evaluation of the applicability in different production scenarios presented, with specific focus on surface accessibility, nano structures uniformity and applicability to surfaces with complex geometry