The chick limb bud is unable to mount a regenerative response following amputation at any stage of its development. Local application of heparan sulfate conjugated beads loaded with fibroblast growth factor-2 (FGF-2) onto an amputated stage 25 chick limb bud results in a high frequency (88%) of limbs in which the regeneration of digit-like structures was induced. The regenerative response is associated with the location of the FGF-2-loaded beads on the limb stump. This is the first report of the induction of a regenerative response in a higher vertebrate limb by a chemically defined agent.
