Chinese Acupuncture Guided by External Magnetic Field for Localized Analgesia

Pain, arising from chronic abnormal activation of nerves and tissues, contributes to dysfunction and reduced quality of life. A single mechanism and short duration of action limit the effectiveness of current local analgesics. Chinese Acupuncture (CA) influences the immune-neural circuit by triggering mast cell (MC) degranulation at acupoints but lacks precise control. This study introduced a magnetoelectric hydrogel acupuncture system that responds to external magnetic stimulation. Using screw-threaded needles, a hydrogel containing magnetically responsive piezoelectric nanoparticles was accurately administered to pain-related acupoints, targeting MCs. Under magnetic fields, these nanoparticles produce coupled “mechanical force-electrical” stimulation, promoting MC degranulation and converting physical cues into biochemical mediators acting on nerve endings to achieve analgesia. In vitro, the system enhanced Ca 2 + influx and RBL-2H3 degranulation, leading to the secretion of mediators such as histamine, 5-HT, and ATP. In vivo validation confirmed the system's specific activation of MCs beneath the ST-36 acupoint, specifically triggering MC degranulation and regulating peripheral TRPV1 and dorsal root ganglia A1R expression, thus inhibiting pain transmission. Decreased proinflammatory cytokines, elevated cerebrospinal β-endorphin, and improved pain thresholds indicated integrated immune–neuro–endocrine regulation. In conclusion, this magnetoelectric hydrogel acupuncture enables effective and sustained analgesia via controllable MC-mediated neuroimmune modulation.