Harmonizing dual electrospun/sponge structures within a triad gellan gum/eucalyptus/Cu-doped baghdadite composition for bone tissue engineering

Bone tissue engineering strives to leverage successful material designs to regenerate highly innervated structures of bone. Biocomposites that combine both nano- and micro-scale porosities offer a promising approach in this field. Herein, we developed a gellan gum-based sponge covered with electrospun gellan gum fibers as a bilayer bone scaffold. To improve its functionality, we added eucalyptus extract and enriched the electrospun coating with copper-doped baghdadite. The results displayed coating of the sponge's micropores (157 ± 71 μm) with the fine fibers (424 ± 222 nm). Loading 6 wt % copper-doped baghdadite enhanced hydrophilicity, lowering the contact angle by 10° and increasing the swelling ratio to 55.79 %. Mechanical investigation revealed a two-phase tensile transition, highlighting the benefits of sponge and fibers in a single architecture, with a compressive strength of 383.01 kPa. Embedding fillers caused a significant enhancement in the antibacterial performance and inclined the antioxidant activity up to 97.53 %. Although eucalyptus inhibited the MG63 cell growth and attachment regarding its high antioxidant activity, loading 6 wt % Cupper-doped baghdadite created favorable conditions for cellular behavior on both sponge and electrospun surfaces. Taken together, the findings highpoint the potential of the designed scaffold as a multifunctional platform for bone tissue regeneration.