Neurological disorders have been increased in the last years, affecting over one billion people globally. The lack of successful treatments is related to the low brain bioavailability of potent drugs to reach the brain due to the blood-brain-barrier (BBB) crossing. To overcome this limitation, high concentrations of drugs are administered to patient in order to reach brain more efficiently, leading consequently to off-target organ toxicity. For that reason, there is an urgent need to improve neurological disorders with powerful treatments. Drug delivery nanosystems have been explored due to their targeting properties. Chitosan is a natural polymer widely used to formulate drug delivery nanosystems, allowing a targeted therapy with no toxicity due to its unique properties, such as biocompatibility, biodegradability and mucoadhesive properties. Drug delivery nanosystems, hydrogels and scaffolds composed chitosan have recently been used for brain delivery, targeting different neurological disorders. Besides intravenous administration of chitosan-based nanocarriers for brain delivery, intranasal administration has been an alternative due to its mucoadhesive properties, improving the patient adhesion to therapy. This review will focus on most recent approaches of chitosan-based nanomedicine for brain delivery, from drug delivery systems to scaffolds for brain regeneration.

近年来，神经系统疾病有所增加，影响了全球超过10亿人。缺乏成功的治疗方法与有效药物因血脑屏障（BBB）穿越导致大脑到达大脑的生物利用度低有关。为了克服该限制，向患者施用高浓度的药物以更有效地到达大脑，从而导致脱靶器官毒性。因此，迫切需要通过有效的治疗方法来改善神经系统疾病。由于其靶向性质，已经研究了药物递送纳米系统。壳聚糖是一种天然聚合物，广泛用于配制药物输送纳米系统，由于其独特的特性（例如生物相容性，生物降解性和粘膜粘附特性​​），因此可以进行无毒的靶向治疗。最近，由壳聚糖组成的药物递送纳米系统，水凝胶和支架已用于针对不同神经系统疾病的脑部递送。除了静脉内施用基于壳聚糖的纳米载体用于脑部输送外，鼻内给药由于其粘膜粘附特性​​而成为一种替代选择，从而改善了患者对治疗的粘附性。这篇综述将聚焦于基于壳聚糖的纳米药物用于脑部输送的最新方法，从药物输送系统到用于脑部再生的支架。改善患者对治疗的依从性。这篇综述将聚焦于基于壳聚糖的纳米药物用于脑部输送的最新方法，从药物输送系统到用于脑部再生的支架。改善患者对治疗的依从性。这篇综述将聚焦于基于壳聚糖的纳米药物用于脑部输送的最新方法，从药物输送系统到用于脑部再生的支架。