Transplantation of layer-by-layer assembled neural stem cells tethered with vascular endothelial growth factor reservoir promotes neurogenesis and angiogenesis after ischemic stroke in mice

•LbL assembled NSCs were successfully constructed using gelatin and hyaluronic acid.•LbL-NSCs are biocompatible, and hold the ability of promoting NSCs differentiation into neurons.•Transplantation of LbL (VEGF)-NSCs promote implanted NSCs survival and differentiation into neurons after dMCAO.•Engraftment of LbL (VEGF)-NSCs reinforce neurogenesis, angiogenesis, survival of host neurons, and BBB repair.•LbL (VEGF)-NSCs facilitate host neurocytes survival and neuroblasts migration.