 The current state of vascular prosthesis, grafts, has been limited by their size, which has prevented them from being used in smaller diameter reconstructions. Recent studies suggest that the biocompatible biomaterials that make up these grafts may actually be limiting their use due to their ability to form dense, non-vessel-like capsules around the implanted material. By contrast, other materials that promote tissue regeneration and vasculature could potentially provide better results. These materials could lead to a new generation of vascular grafts that are suitable for smaller diameter reconstructions. This article was authored by Buddy Ratner.