A novel methodology to surface modify bioactive glasses with hydroxyapatite having multiscale periodic porosity

Multiscale biomimetic surfaces with hierarchical organization are essential for improving the integration of implants into biological tissues, as they enhance cellular interactions and closely mimic natural tissue architectures. Despite the availability of various fabrication techniques, many are expensive and difficult to scale up. To overcome these challenges, the authors present a novel and tailorable method to fabricate a multiscale honeycomb-like hydroxyapatite/hydroxycarbonate apatite (HA/HCA) structure on clinically employed bioactive glass (BG) substrates. S53P4 was selected as the optimal substrate for this proof of concept as FDA-approved and commercially available. The developed method involves the deposition of polystyrene (PS) beads onto S53P4 surface, the immersion in simulated body fluid (SBF) to promote the nucleation and growth of HA/HCA crystals between the tightly packed beads, finally removed by calcination. The morphological and physicochemical analyses showed a superhydrophilic HA/HCA layer with nanoscale features (nanoroughness), microscale porosity (after bead removal), and centimeter-scale periodicity (from bead arrangement). Fibrinogen (FGN), employed as a model protein to simulate the early-stage biological environment, showed high affinity with the engineered surface, leading to a stable charge and low risk of fibrillogenesis. Therefore, the developed surface, closely replicating bone-enamel, shows potential for bone engineering and post-surgical thrombosis prevention.