Enhancing bone regeneration with bionic hydrolysis and biomimetic polydopamine coating on 3D-printed PCL scaffolds: A comparative study

Surface modification can enhance the biological properties of polycaprolactone (PCL) scaffolds. In this study, bionic hydrolysis and biomimetic polydopamine (PDA) coating were investigated, individually and in combination, to enhance the bioactivity of inner cube 3D-printed PCL scaffolds. The modified scaffolds were evaluated for their bioactivity, and the underlying mechanism was studied based on their physiochemical properties. The modifications significantly improved the surface roughness, hydrophilicity, surface adhesion ability, and biological properties of the scaffolds. The hydrolyzed PCL scaffolds exhibited micro-cracks and pits on their surface, with carboxyl and hydroxyl groups present. PDA, in the form of micro-particles with phenolic hydroxyl and amino groups, was coated onto the PDA-coated scaffolds. The combination-treated scaffolds had shallower pits, smaller particles, and lower levels of phenolic hydroxyl and amino groups. PDA coating demonstrated the best properties in promoting the adhesion, proliferation, and osteogenesis of rat bone marrow mesenchymal stem cells. Although the combination-treated scaffolds showed better cell proliferation than the hydrolyzed scaffolds, they did not exhibit a synergistic effect on osteogenic induction, instead weakening the osteogenic induction ability of the PDA-coating and hydrolysis treatments. Therefore, the material’s characteristics and the substantial variation of different chemical reactions must be considered during biological material modification.