Hybrid nanogenerator based closed-loop self-powered low-level vagus nerve stimulation system for atrial fibrillation treatment

Atrial fibrillation is an"invisible killer"of human health.It often induces high-risk diseases,such as myocardial infarction,stroke,and heart failure.Fortunately,atrial fibrillation can be diagnosed and trea-ted early.Low-level vagus nerve stimulation(LL-VNS)is a promising therapeutic method for atrial fibril-lation.However,some fundamental challenges still need to be overcome in terms of flexibility,miniaturization,and long-term service of bioelectric stimulation devices.Here,we designed a closed-loop self-powered LL-VNS system that can monitor the patient's pulse wave status in real time and con-duct stimulation impulses automatically during the development of atrial fibrillation.The implant is a hybrid nanogenerator(H-NG),which is flexible,light weight,and simple,even without electronic circuits,components,and batteries.The maximum output of the H-NG was 14.8 V and 17.8 μA(peak to peak).In the in vivo effect verification study,the atrial fibrillation duration significantly decreased by 90％after LL-VNS therapy,and myocardial fibrosis and atrial connexin levels were effectively improved.Notably,the anti-inflammatory effect triggered by mediating the NF-κB and AP-1 pathways in our therapeutic system is observed.Overall,this implantable bioelectronic device is expected to be used for self-powerability,intelligentization,portability for management,and therapy of chronic diseases.