This invention provides a composition for controlled-release of polypeptide growth factors useful in tissue repair or engineering. The composition include a polypeptide growth factor covalently cross-linked to a biocompatible substrate by a transgultaminase. The cross-linking tethers the growth factor to a substrate so that it will not diffuse away from the desired site of application. It also concomitantly inactivates the growth factor. Release and reactivation of the growth factor can be achieved by endogenously produced metalloproteinase (MMPs) or exogenously provided proteases such as collagenases. Also provided are scaffolds, transplant devices, methods for using the same and methods for making the same,
