INSTRUCTIVE MEMBRANES FOR NEURONAL REGENERATION

Many strategies are aimed to develop biomaterials for supporting and inducing neuronal regeneration. Polymeric semipermeable membranes are attractive for their high selective properties for creating the microenvironment in order to promote neuron adhesion and growth. Micro- and nano-structured membranes would be able to modulate the adhesion, proliferation and differentiation of cells, which are fundamental processes for tissue regeneration by governing the mass transfer of molecules that generate a precisely controlled microenvironment mimicking the specific features of in vivo environment. Membranes may guide the axon regeneration with the surface geometry by controlling the mass transfer of molecules between the cell microenvironment and the external milieu, providing to the cells chemical, physical and topographical features similar to those of the complex in vivo extracellular matrix through patterns of chemistry and topography from macroscale to nanoscale. In addition, the membrane surface can be tailored with proteins, peptides and cell-specific recognition factors by modification processes in order to stimulate specific cell responses and maintain differentiated functions. In this paper the author will present the controlled design and preparation of polymeric membranes with appropriate physical, chemical and biological cues, which are relevant to induce the neuronal regeneration. In particular the influence of membrane configuration (e.g., flat, tubular), surface properties (e.g., roughness, pore size, porosity, topographical features), and physico-chemical properties (e.g., wettability) on neuronal outgrowth and differentiation as well as the membrane ability to reconstruct the neuronal network will be discussed. Neurite outgrowth and the orientation of cellular growth, which are two important processes, can be facilitated by designing a well-defined cellular pattern. Recent results in the development of synthetic and biodegradable membranes with tailored physical, chemical and morphological properties, which are engineered to stimulate neurite outgrowth, will be discussed.