**10. Nanomaterials incorporated with stem cells to prompt healing**

Therapeutic approaches for wound healing that involves stem cells have been studied extensively in the past, and they have shown great promise in promoting angiogenesis and facilitating re-epithelialization [185]. Adipose-derived stromal cells (ASCs), bone marrow (BM)-derived endothelial progenitor cells, BM-derived mesenchymal stem cells (BM-MSCs), BM-derived mononuclear cells (BM-MNCs), placentaderived SCs, and umbilical cord-derived MSCs have been shown to have a therapeutic role in wound repair [185, 186]. The probable mechanism of action is, however, not well elucidated, but the hypothesis says that SC therapy tends to provide a dynamic wound microenvironment *via* their paracrine effect, hence, hastening the healing cascade [187]. In a recent study, it was shown that when MSCs are directly delivered to the wound site, they induce cell death; this effect was then attenuated by using bioengineered delivery platform for therapies [188].

Currently, SCs are used for local administration to wounds by the way of dressings, injections, sprays, and systemic administration. Recently, nanotechnology-driven approaches were employed to synthesize nanomatrices possessing customized biophysical properties, leading to controlled differentiation of SCs. BM-MSCs attached to collagen/PLGA nanofiber scaffold showcased faster closure of wounds [189]. The BM-MSC/nanoscaffold composite approach was explored for wound healing and regeneration (**Figures 2** and **3**). Subsequently, a mixture of MSCs, growth factors, and the matrix was used in the production of nanoscaffolds to mimic human skin characteristics [187, 190]. Polymeric nanofibers having biomimetic potential can simulate the native tissue thereby forming an ideal SC niche. Despite significant advancements in this field in the past, no SC therapy for chronic wound management has yet been FDA approved [185]. It is highly likely that in the future, viable treatments will use SCs in combination with other local/systemic therapies.
