Controlling Preosteoblast Behavior through Manganese Vacancy‐Rich Birnessite with Enhanced Divalent Cation Modulation of Fibronectin–Integrin Interactions. Issue 12 (29th April 2020) - Liu, Shiwei
Abstract: The osteoblast‐function associated integrin–ligand interactions are known to be dependent on divalent cations, but there is scarce information about the effect of Ca 2+ and Mg 2+ adsorption properties of an implant surface on integrin α5 β1 –fibronectin interactions and the subsequent osteoblast behavior. Cation adsorption properties are closely associated with the extent of structural defects in materials. Here, the birnessite‐type MnO2 coatings with different amounts of manganese vacancy ( V Mn ) are prepared on Ti substrates via hydrothermal treatment (denoted as 1M100‐Ti, 5M100‐Ti, and 5M120‐Ti). The 5M120‐Ti surface with hierarchical flower‐like structure and the most stacked [MnO6 ] layers possess the highest V Mn content, which is determined by the ratios of Mn 3+ /Mn 4+ and K/Mn. The increased V Mn content enhances the Ca 2+ and Mg 2+ adsorption properties of the birnessite coatings. When immersed in Ca 2+ /Mg 2+ aqueous solution, the birnessite coatings significantly promote fibronectin adsorption and the exposure of cell‐binding domains on adsorbed fibronectin with 5M120‐Ti showing the greatest enhancement. Accordingly, the 5M120‐Ti surface provides more α5 β1 ‐integrin‐specific instructions to MC3T3‐E1 preosteoblasts capable of enhancing spreading and osteoblastic differentiation compared to two other samples. This study may provide a prospective approach of modulation of integrin–ligand interactions for controlling cell behavior by adjusting metal vacancies in metal oxides coatings. Abstract : The birnessite‐type MnO2 coating can enhance the Ca 2+ and Mg 2+ adsorption by increasing the V Mn content. When immersed in a fibronectin solution containing physiological levels of Ca 2+ and Mg 2+, the MnO2 coating activates the adsorbed fibronectin. The MnO2 coating with high ion adsorption capacity facilitates the anchoring and differentiation of preosteoblasts via the enhanced integrin α5 β1 –fibronectin interactions.