Mechanical properties of femtosecond laser-patterned micro-implant structures

Abstract

Laser-induced periodic surface structures (LIPSS) are promising functionalizations of metallic implant surfaces, particularly cardiovascular stents, where improved endothelialization and reduced neointimal hyperplasia are desired. However, typical stent struts are highly sensitive to microstructural material changes, making it essential that laser structuring does not compromise mechanical integrity. Previous studies have shown that LIPSS formation induces microstructural changes such as grain refinement, increased dislocation density, and residual stresses extending several micrometers into the material. These effects result from ultrafast melting and rapid resolidification and can alter local mechanical properties. This study investigates the influence of LIPSS generated by femtosecond pulses on the macroscopic mechanical behavior of stainless steel using three-point bending tests. LIPSSfunctionalized and unstructured samples are compared to evaluate changes in the Young’s modulus, providing insight into the safe application of LIPSS on microstructured medical devices.