Abstract: A system for stabilizing fibroblast-derived growth factors, maintaining their bioactivity over a prolonged period of time and controllably releasing them for use is disclosed. The system uses growth factors bound to biocompatible substrates via heparin or heparin derived compounds to maintain the bioactivity of the growth factors. A growth factor bound to a heparin coated substrate can be used independently as a controlled release device, or can be incorporated into a reservoir or matrix type controlled release devices to further enhance the controlled release properties. The stabilized growth factors can be implanted into a patient, thereby providing a means for producing an in vivo controlled release of a growth factor to the patient.