Surface modification of electrospun nanofibrous scaffolds via polysaccharide–protein assembly multilayer for neurite outgrowth

Abstract

In this study, we present a simple yet efficient method to modify polyester electrospun fibrous scaffolds by polysaccharide–protein multilayer formation based on electrostatic interactions. Chitosan (CS) and gelatin (Gel) was selected as the polycation and polyanion, respectively, to build polyelectrolyte multilayers (PEMs) on poly-L-lactide (PLLA) electrospun fibers via layer-by-layer (LbL) self-assembly technique. A positively charged surface was first created via the aminolysis reaction of esters in the PLLA backbone by poly(ethylene imine) (PEI), followed by consequent alternate deposition of Gel and CS. FTIR and XPS measurements confirmed alternative coating of Gel and CS, while SEM observation indicated that the scaffolds maintained the porous and fibrous morphology during PEM development. IMARIS software, which was extensively employed to reconstruct 3D images, was employed to visualize the architecture of neuronal networks and neurite development of single neurons. Our results indicated that the PEM-modification significantly enhanced cell–matrix interactions by improving cell viability and neurite outgrowth. Significantly more branches and longer neurites were obtained on Gel/CS PEM-coated fibrous scaffolds than PLLA fibrous scaffold and those after Gel or CS monolayer modification. Moreover, the component of the outermost layer showed influence on neuron growth in terms of higher cell viability as well as more branches and longer neurites being obtained on Gel-outermost coated fibrous scaffolds than those outermost coated with CS. The current study indicated that the polysaccharide–protein assembly multilayer could be employed to modify the surface of polyester fibers, thus providing a new strategy to fabricate biomimetic scaffolds for nerve tissue engineering.