Functionalized magnesium-zinc surfaces for biodegradable implants: Nd:YAG machining and hot pressing approach

• Nd:YAG laser was used to machine the surface of pure Mg. • The laser action strongly depends on the selected parameters, exhibiting different geometries. • This method allows the production of grooves to be used as a pre-step for surface alloying. • Alloying by means of Hot-Pressing with zinc was successfully achieve. • Alloying with zinc did slower the degradation rate. The design of a bio-absorbable load-bearing endosseous implant must ponder on different aspects, as an adequate absorption rate compatible with that of bone regeneration. During this biodegradation process it is necessary to maintain the material mechanical properties at a minimum level, while controlling the biodegradation products that although non-toxic in controlled amounts, can pose severe problems in increased quantities. This study explores the laser machining of pure magnesium (Mg) using a Nd:YAG laser through two distinct approaches to obtain grooves with different geometries. That are then aiming functionalized with zinc (Zn) by hot pressing technique, to control the dissolution rate. Groove morphology was shown to strongly depend on laser parameters, with round-bottom geometries (A3 and A4) enabling more uniform Zn filling. Dissolution testing in simulated body fluid revealed that Zn-functionalized grooves significantly reduced degradation, with Zn-A3 and Zn-A4 exhibiting degradation rates of 3.98 ± 0.02 and 1.12 ± 0.01 mg/cm²/h, respectively. In contrast, E1 showed rapid initial dissolution due to incomplete Zn integration.