Facile surface functionalization with glycosaminoglycans by direct coating with mussel adhesive protein

The use of mussel adhesive proteins (MAPs) as a surface coating for cell adhesion has been suggested due to their unique properties of biocompatibility and effective adhesion on diverse inorganic and organic surfaces. The surface functionalization of scaffolds or implants using extracellular matrix (ECM) molecules is important for the enhancement of target cell behaviors such as proliferation and differentiation. In the present work, we suggest a new, simple surface functionalization platform based on the charge interactions between the positively charged MAP linker and negatively charged ECM molecules, such as glycosaminoglycans (GAGs). MAP was efficiently coated onto a titanium model surface using its adhesion ability. Then, several GAG molecules, including hyaluronic acid (HA), heparin sulfate (HS), chondroitin sulfate (CS), and dermatan sulfate (DS), were effectively immobilized on the MAP-coated surfaces by charge interactions. Using HA as a model GAG molecule, we found that the proliferation, spreading, and differentiation behaviors of mouse preosteoblast cells were all significantly improved on MAP/HA-layered titanium. In addition, we successfully constructed a multilayer film on a titanium surface with oppositely charged layer-by-layer coatings of MAP and HA. Collectively, our simple MAP-based surface functionalization strategy can be successfully used for the efficient surface immobilization of negatively charged ECM molecules in various tissue engineering and medical implantation applications.