AbstractChronic non-healing wounds, frequently caused by diabetes, lead to lower quality of life, infection, and amputation. These wounds have limited treatment options. We have previously engineered growth factors to bind to exposed extracellular matrix (ECM) in the wound environment using the heparin-binding domain of placental growth factor-2 (PlGF-2_123–144), which binds promiscuously to ECM proteins. Here, in the type 1 diabetic (T1D) NOD mouse model, engineered growth factors (eGFs) improved both re-epithelialization and granulation tissue formation. eGFs were even more potent in combination, and the “triple therapy” of vascular endothelial growth factor-A (VEGF-PlGF-2_123–144), platelet-derived growth factor-BB (PDGF-BB-PlGF-2_123–144), and heparin-binding epidermal growth factor (HB-EGF-PlGF-2_123–144) both improved wound healing and remained at the site of administration for significantly longer than wild-type growth factors. In addition, we also found that changes in the cellular milieu of a wound, including changing amounts of M1 macrophages, M2 macrophages and effector T cells, are most predictive of wound-healing success in the NOD mouse model. These results suggest that the triple therapy of VEGF-PlGF-2_123–144, PDGF-BB-PlGF-2_123–144, and HB-EGF-PlGF-2_123–144may be an effective therapy for chronic non-healing wounds in that occur as a complication of diabetes.