Nanotechnology-based delivery systems to release growth factors and other endogenous molecules for chronic wound healing

The topical administration of growth factors (GFs) and other endogenous molecules (insulin, insulin like GF-1, stromal-cell derived factor, LL37, vasoactive intestinal peptide, heparin, melatonin, lipocalin, serpin-A1 and β-stradiol) have proven to enhance chronic wound healing. However, their low stability in vivo makes necessary to improve their administration in terms of dose, delivery system and security. In that regard, novel drug delivery systems (DDSs) have been used to address this problem, since they are able to release drugs in a localized and controlled manner, protecting them from the proteases present in wound bed. Among them, DDSs based in nanotechnology can be highlighted such as, polymeric or lipidmicro- and nanoparticles, lipid nanoparticles and nanofibrous membranes. The aim of this review is to provide an overview of nanotechonology based DDSs for the controlled release of endogenous molecules. In addition, an insight about the role of GFs in wound healing and the most common biomaterials used in DDSs are also given. Those formulations present numerous advantages, such as protection of the drug, good biocompatibility, controlled or sustained release, high drug-loading and good mechanical properties. Overall, the controlled release of GFs incorporated into nanotechnology based DDSs has demonstrated a great potential for chronic wound healing.