In one aspect, the invention provides methods for forming a target tissue substitute. The methods of the invention comprise the following steps: (a) providing a scaffold comprising one or more layers of one or more arrays of microfibers, wherein one or more of the arrays of microfibers is designed to mimic the configuration of one or more structural elements in a target tissue; and (b) culturing cells on the scaffold to form a target tissue substitute. In another aspect, the invention provides implantable medical devices. The implantable medical devices of the invention comprise a scaffold comprising one or more layers of one or more arrays of microfibers, wherein one or more of the arrays of microfibers is arranged to mimic the configuration of one or more structural elements in a target tissue. Typically, cells are cultured on the scaffold to form a target tissue substitute.