Three-dimensional fibrous scaffolds with microstructures and nanotextures for tissue engineering

Much effort has been dedicated to developing scaffolds that can mimic native microenvironments to promote tissue regeneration. A natural tissue scaffold provides not only a three-dimensional (3-D) structural support but also nanotextured surfaces comprising of a fibrous network for cell adhesion and signaling. In addition to its function as a structural template, the scaffold also increases cell-cell and cell-matrix interactions, which in turn directs cell proliferation and differentiation. Microfabrication techniques can create 3-D scaffolds with microporous structures, which are important to cell infiltration and nutrients transport. Nanofabrication techniques can be used to create surfaces with desirable chemistry and nanotopography, which has led to remarkable findings on how surfaces, through their nanoscale features, affect cellular behaviors. Tissue regeneration requires 3-D scaffolds with both microporous structures and nanotextured surfaces. However, scaffolds created by microfabrication usually lack a nanotextured surface, while nanotextured scaffolds generated from nanofabrication lack a 3-D microenvironment. Recent research in tissue engineering has paid great attention to combining these two scaffold features and developing novel methods for their fabrication. In this review paper, we first give a brief introduction on the influence of 3-D microstructures and nanotopographies on cellular functions, including cell adhesion, proliferation, morphogenesis and differentiation. Recent development of fabrication methods to produce 3-D fibrous scaffolds with microporous structures and nanotextures is then discussed with some examples of their applications.