Surfactant-immobilized fibronectin enhances bioactivity and regulates sensory neurite outgrowth

A PEO-containing surface coating was investigated as a means to control neurite outgrowth in the presence of serum. Various ratios of end-group-activated tri-block copolymer Pluronic F108 were used to immobilize the extracellular matrix protein fibronectin (FN). Primary cultures of dorsal root ganglion neurons were cultured on F108-immobilized FN or, as a control, on FN adsorbed from solution directly to polystyrene. Although FN surface concentration could be controlled in a dose-dependent manner by either technique, dose-dependent control of neuronal behaviors was best achieved on F108-immobilized FN. This effect was similar regardless of the presence of serum in the culture medium. F108-immobilized FN supported twofold greater maximal neurite outgrowth than did directly adsorbed FN. Furthermore, at similar surface concentrations, F108-FN was significantly more active in promoting neurite outgrowth. Polypropylene filament bundles treated with F108-immobilized FN supported robust outgrowth from explants of dorsal root ganglia, demonstrating the utility of the surface coating on clinically relevant materials with more complex shapes. The ability to control neuronal behaviors in a serum-resistant manner, coupled with enhanced biologic activity, demonstrates the potential for surfactant-based immobilization as a method for generating biointeractive materials for tissue engineering.