Hierarchical laminin-MgCO₃ gradient layers on Sr/ZnO ion-implanted titanium for multifunctional bone regeneration

Given that the bio-inert behaviour of the Ti surface presents a challenge under certain compromised conditions, it is necessary that the surface is tuned to ensure strong osseointegration between the implant and the adjacent bone. The present study is aimed at modifying Ti surface through ion implantation of Sr²⁺ and Zn²⁺ to form zinc oxide/strontium doped-Ti surface and incorporate magnesium carbonate (MgCO₃, MC) in the coating via a low-temperature high-speed collision (LTHSC) technique. This was subsequently followed by a dip-coating of laminin (Lam) layer. This MC-ZnO/Sr-Lam coated (MC wt% = 10%, 20%, 30%) Ti substrate was subjected to physical and biological characterizations. The 10MC-ZnO/Sr-Lam coating showed the highest adhesion strength (27.1 ± 1.28 MPa) and lowest contact angle (∼38°±1.74), indicating superior coating stability and wettability. Mg²⁺ release was concentration-dependent, ranging from ∼6.5 to 588.6 ppm, with 20MC-ZnO/Sr-Lam delivering an optimal sustained release adhesion and proliferation, with the 30MC-ZnO/Sr-Lam coating demonstrating highest upregulation of osteogenic markers (RUNX2, COL1 and OCN) relative to Ti. Overall, the 20MC-ZnO/Sr-Lam coating provided the best balance between adhesion strength, controlled ion release, osteogenic enhancement and antibacterial efficacy, highlighting its potential as an optimized surface modification strategy for multifunctional bone implant applications.