A nanofiber comprising a cross-linkable protein polymer and a transglutaminase. A method for producing a nanofiber, the method comprising: combining a first solution comprising a cross-linkable protein polymer and a second solution comprising a transglutaminase to produce a liquid electro spinning mixture (LEM) characterized by an environment that is unsuitable for the transglutaminase to be enzymatically active on the cross-linkable protein polymer; and electro spinning the LEM to form a nanofiber comprising the TGase and the cross-linkable protein polymer.