DermaPure™ is a decellularized dermal skin substitute using the Tissue Regenix dCELL® patented Technology to remove cells and other components from human and animal tissue while maintaining the native structural and biomechanical properties. The primary objective of the study is to establish the wound healing performance and safety of DermaPure™ over a 12 week period, when administered to "hard to heal" chronic, neuropathic diabetic foot ulcers. This study has been designed to compare the performance of DermaPure™ (in combination with standard care) versus standard care alone.