NIR responsive microneedles patch used for promoting spinal cord injury repair by modulating mitochondrial ROS microenvironment

Spinal cord injury (SCI) is a serious traumatic disease of the central nervous system. How to effectively deliver drugs to the site of spinal cord injury lesions through the blood spinal cord brain barrier (BSCB) has always been a challenge. There is an urgent need for developing a controllable and effective method to continuously release drug for SCI repair. Microneedles are a promising drug delivery method, however, how to control drug release smartly from microneedles remains a cutting-edge field. Herein, a NIR triggered photothermal responsive microneedles patch with Au@polyphenol nanospheres encapsulated was designed for SCI repair. By regulating the NIR irradiation, the thermal swelling rate of the microneedles can be precisely controlled. Therefore, the releasing of Au@polyphenol nanospheres from the microneedles could be controlled. Gold nanoparticles are known as nanozyme in photothermal therapy. Polyphenol nanospheres released from microneedles are helpful in promoting spinal cord injury repair by modulating mitochondrial ROS microenvironment. This NIR responsive microneedles array patch loaded with gold@polyphenol nanospheres has the advantages of effectively clearing reactive oxygen species, promoting mitochondrial autophagy, rebuilding redox balance, and reducing neuronal apoptosis.