The invention provides a composition comprising a nanofiber polymer in which the fibers of the nanofiber polymer are aligned, and a molecule is covalently attached, either directly or through a linker, to the nanofiber polymer. This molecule is capable of either covalently or non-covalently attaching to a member selected from an extracellular matrix component, a growth factor, and combinations thereof. The invention also provides methods of making the composition and methods of using the compositions to add new tissue to a subject, such as a human.