Tailoring adaptive bioresorbable Mg-based scaffolds with directed plasma nanosynthesis for enhanced osseointegration and tunable resorption

A schematic representation of the surface modification process of Mg-based foams by DPNS (directed plasma nanosynthesis). Irradiation (left): The transformation of the surface under Ar+ ions bombardment is presented. Initial oxide layers are removed, and the MgO layer is nanostructured. Then, an Al supply from the interior of the alloy can be accelerated via irradiation-enhanced Gibbsian segregation to the layer adjacent to the oxide. Immersion (right): The transformation of the surface after immersion in DMEM is illustrated; various combinations of DPNS parameters, including incident energy, fluence, and incident angle with respect to the surface normal, led to varied surface chemistry topography. [Display omitted] •Porous AZ31 was modified at the nanoscale via directed plasma nanosynthesis (DPNS).•Ar+ irradiation modified the nanotopography and chemistry of the outer surface.•Al segregation on porous AZ31 surfaces was dependent on the DPNS parameters.•DPNS allowed the tunability of the hydrogen release of porous AZ31.•DPNS improved the apatite formation ability in porous AZ31. Directed plasma nanosynthesis (DPNS) is a plasma-based surface modification process used to provide high-fidelity bioactive and bioresorbable interfaces for Mg-based foams having an average 500-μm pore size and containing main components of Al, Zn and Ca at bal., 3.3%, 1.11%, and 0.21%, respectively. Correlations of incident particle energies of 400–700 eV and room temperature, normal and off-normal incidence angles of 0° and 60°, respectively, and high-ion fluence conditions are combined to elicit a bioreactive Mg-foam surface. H2 evolution and pH levels of irradiated and non-irradiated Mg-foams were examined and correlated to the DPNS parameters. In situ X-ray photoelectron spectroscopy and focused ion-beam results have shown that energies of ~ 400–700 eV can control surface topography and composition, which, in turn, controls the foam-corrosion mechanism. Samples are immersed in Dulbecco’s modified eagle media, and a synergistic reaction is found in which the irradiated samples enhance the formation of calcium–phosphate (CaP) phases to CaP ratios close to the hydroxylapatite phase that enhances bone-tissue regeneration. These results lead to a surface modification strategy that adjusts the interaction of the material and the environment without using a coating that could affect the geometry and the bulk properties of the porous material.