A two-step strategy to deposit a hydroxyapatite coating on polydopamine-coated polymer fibers

As the main inorganic component of human bones and teeth, hydroxyapatite (HA), with excellent bioactivity and biocompatibility, shows great potential in the bone tissue engineering field. Marine mussel-inspired polydopamine (PDA) possesses unique functional groups and thus can absorb the calcium ions from extracellular fluid, thereby triggering the precipitation of HA. This study is based on a two-step strategy. Using the chemical activity of PDA, polyvinyl alcohol/polylactic acid (PVA/PLA) braids were coated with a PDA layer that served as a template for the electrochemical deposition of a HA layer. The test results indicate that the resulting HA crystals were assembled on the polymer fibers in an urchin-like mannerwith a stratified structure. Subsequently, the HA/PDA-PVA/PLA braided bone scaffolds were immersed in simulated body fluid for ten days, after which the bone scaffolds were found to be completely coated with HA, indicating a good biomineralization capability. Cell activity of HA/PDA-PVA/PLA scaffolded by dopamine-assisted electrodeposition was 178.8% than that of PVA/PLA braids. This HA coating layer inspired by biochemical strategies may be useful in the field of bone tissue engineering.