The present invention is directed stromal cell derived factor-1 peptides that have been mutated to make them resistant to digestion by the proteases dipeptidyl peptidase IV (DPPIV) and matrix metalloproteinase-2 (MMP-2) but which maintain the ability of native SDF-1 to attract T cells. The mutants may be attached to membranes formed by self-assembling peptides and then implanted at sites of tissue damage to help promote repair.