Microneedle biosensor for real-time monitoring of hydrogen sulfide release from paraventricular nucleus of hypertension rats stimulated by electroacupuncture

Acupuncture therapy reduces blood pressure in hypertensive patients by stimulating acupoints located at specific anatomical positions with needles. Hydrogen sulfide (H₂S) release and accumulation in the paraventricular nucleus (PVN) might be a pivotal step for triggering blood pressure reduction. But to date, the dynamics of H₂S in the PVN during acupuncture treatment remain unclear. In this work, a multiple-nanomaterial-functionalized microneedle sensor is prepared for real-time monitoring of H₂S in the PVN of rat while stimulated by electroacupuncture. Gold nanoparticles (AuNPs), molybdenum disulfide (MoS₂) and Ag₂S were sequentially layered on the needle surface. The excellent electrical conductivity of AuNPs, the high carrier mobility of MoS₂ and the high catalytic performance of Ag₂S ensure sensitive and specific detection of H₂S in the range of 1 μM-100 μM with detection limit down to 95 nM. The microneedle sensor also demonstrates exceptional stability, remaining effective at room temperature for up to two weeks. Based on this, the microneedle sensor is used to monitor H₂S release in vivo before and after acupuncture treatment. Our research indicates that acupuncture effectively increases H₂S levels in the PVN of hypertensive rats, contributing to blood pressure reduction. This microneedle sensor provides a reliable method for monitoring H₂S release in vivo, offering valuable insights into the role of H₂S in the neurophysiology of hypertension and the mechanism of acupuncture in its treatment.