Laser Ablated Periodic Nanostructures on Titanium and Steel Implants Influence Adhesion and Osteogenic Differentiation of Mesenchymal Stem Cells

Abstract

Metal implants used in trauma surgeries are sometimes difficult to remove after the completion of the healing process due to the strong integration with the bone tissue. Periodic surface micro- and nanostructures can directly influence cell adhesion and differentiation on metallic implant materials. However, the fabrication of such structures with classical lithographic methods is too slow and cost-intensive to be of practical relevance. Therefore, we used laser beam interference ablation structuring to systematically generate periodic nanostructures on titanium and steel plates. The newly developed laser process uses a special grating interferometer in combination with an industrial laser scanner and ultrashort pulse laser source, allowing for fast, precise, and cost-effective modification of metal surfaces in a single step process. A total of 30 different periodic topologies reaching from linear over crossed to complex crossed nanostructures with varying depths were generated on steel and titanium plates and tested in bone cell culture. Reduced cell adhesion was found for four different structure types, while cell morphology was influenced by two different structures. Furthermore, we observed impaired osteogenic differentiation for three structures, indicating reduced bone formation around the implant. This efficient way of surface structuring in combination with new insights about its influence on bone cells could lead to newly designed implant surfaces for trauma surgeries with reduced adhesion, resulting in faster removal times, reduced operation times, and reduced complication rates.

Laser Direct Writing of Dual-Scale 3D Structures for Cell Repelling at High Cellular Density

“…Of particular interest for the present study, laser surface micro- and nanopatterning evolved into a standalone domain, with extensive applications [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The laser-generated micro- and nanostructures have been used for a wide variety of applications such as to modify the surface wettability [ 24 ] and to control cellular adhesion [ 25 ]. More importantly, laser irradiation of materials provides the tools for the single-step fabrication of dual-scale structures [ 26 , 27 , 28 , 29 ].…”

Laser Surface Modification of Powder Metallurgy-Processed Ti-Graphite Composite Which Can Enhance Cells’ Osteo-Differentiation

“…The advantages are fast machining process, precision, accuracy, versatility and non-contamination of the workpiece [12]. Certain roughness minimization of the heat-affected area and elimination of the cracks on the surface can be achieved by setting the input process parameters in a controlled way [35]. As a technology that provides a suitable alternative to other surface treatment methods of biomaterials, thereby leading to osseointegration improvement, the laser treatment of implants' surfaces is an object of interest for many researchers around the world [34,36,37].…”

Laser Thermochemical High-Contrast Recording on Thin Metal Films

“…However, the diffraction limit restricts the direct laser writing technique. On the other hand, researchers have developed cutting-edge ways to overcome the limit, for instance, direct interference patterning by registration of an interference pattern from two or more laser beams [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Other most recent experiments tackle this problem by the laser-induced formation of oxide layers on metals of titanium (Ti) [ 17 ] and vanadium groups (V, Zr, Ta, et al) [ 18 , 19 , 20 ].…”