Reduce electrical overload via threaded Chinese acupuncture in nerve electrical therapy

Bioelectrical stimulation is a powerful technique used to promote tissue regeneration, but it can be hindered by an "electrical overload" phenomenon in the core region of stimulation. We develop a threaded microneedle electrode system that protects against "electrical overload" by delivering medicinal hydrogel microspheres into the core regions. The threaded needle body is coated with polydopamine and chitosan to enhance the adhesion of microspheres, which are loaded into the threaded grooves, allowing for their stereoscopic release in the core regions. After the electrode is inserted, the microspheres can be delivered three-dimensionally through physical swelling and the shear-thinning effect of chitosan, mitigating the electrical damage. Microspheres are designed to release alkylated vitamin B12 and vitamin E, providing antioxidant and cell protection effects upon in-situ activation, reducing reactive oxygen species (ROS) by 72.8 % and cell death by 59.5 %. In the model of peripheral nerve injury, the electrode system improves the overall antioxidant capacity by 78.5 % and protects the surrounding cells. Additionally, it leads to an improved nerve conduction velocity ratio of 41.9 % and sciatic nerve function index of 12.1 %, indicating enhanced neuroregeneration. The threaded microneedle electrode system offers a promising approach for nerve repair by inhibiting "electrical overload", potentially improving outcomes for tissue regeneration.