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 (H 2 S) release and accumulation in the paraventricular nucleus (PVN) might be a pivotal step for triggering blood pressure reduction. But to date, the dynamics of H 2 S in the PVN during acupuncture treatment remain unclear. In this work, a multiple-nanomaterial-functionalized microneedle sensor is prepared for real-time monitoring of H 2 S in the PVN of rat while stimulated by electroacupuncture. Gold nanoparticles (AuNPs), molybdenum disulfide (MoS 2 ) and Ag 2 S were sequentially layered on the needle surface. The excellent electrical conductivity of AuNPs, the high carrier mobility of MoS 2 and the high catalytic performance of Ag 2 S ensure sensitive and specific detection of H 2 S 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 H 2 S release in vivo before and after acupuncture treatment. Our research indicates that acupuncture effectively increases H 2 S levels in the PVN of hypertensive rats, contributing to blood pressure reduction. This microneedle sensor provides a reliable method for monitoring H 2 S release in vivo, offering valuable insights into the role of H 2 S in the neurophysiology of hypertension and the mechanism of acupuncture in its treatment.