Surface morphology modulation in multilayer scaffolds via ion doping for bone tissue engineering

Abstract

This work proposes the use of multilayer scaffolds as a strategy for developing biomimetic structures for bone tissue regeneration. The scaffolds consist of a glass–ceramic core composed of CaSiO₃/Ca₂P₆O₁₇, which provides mechanical properties of 2.3 MPa and a total porosity of ∼74%. To modify the surface morphology a double bioactive coating consisting of Ca₃(PO₄)₂/CaSiO₃ doped with Na⁺ and K⁺, along with varying amounts of Mg²⁺ (0–0.75 g MgCO₃) was carried out giving a total porosity of 89.8%. The resulting scaffolds were assessed for in vitro bioactivity according to ISO 23317. After immersion in SBF, the W-05 scaffolds displayed diverse surface morphologies: square HA structure (W-05-3D), hollow HA spheres (W-05-7D) and smooth HA layer (W-05-21D). Cell viability of 3T3 fibroblasts exposed to W-05 scaffolds in direct and indirect assays at concentrations of 15 and 30 mg/mL was assessed according to ISO 10993–5. Initially, cell proliferation decreased compared to controls, but differences became non-statistically significant after 72 h. Hollow spheres (W-05-7D) enhanced cell viability compared to other morphologies and plastic controls. Additionally, degradation products of W-05 stimulated cell division, underscoring scaffold biocompatibility.