BDNF and Stroke: Additionally, in this case, hydrogels can be used for the delivery of pharmacological agents, which proved beneficial for stroke, such as erythropoietin (EPO), a cytokine found to promote neurogenesis after AIS [223,231,232]; or vascular endothelial growth factor (VEGF), capable of inducing structural protection after AIS [233,234]; and brain-derived neurotrophic factor (BDNF) [235].