Regulating microglia to modulate the inflammatory response in the early stages of spinal cord injury is crucial for neural repair. Commonly used drugs to inhibit inflammation and microglial activity in clinical practice, such as glucocorticoids and immunosuppressants, are associated with potential side effects. Eleutheroside B (EB), a natural plant extract, has been demonstrated an efficient anti-inflammatory action with low toxicity and the ability to promote neural repair and axon regeneration, suggesting its potential role in treating SCI. Recently, magnetically driven microrobots have demonstrated the ability to deliver drugs and provide precise targeting in deep tissues, which may help increase the dose of EB at the injury site. In this study, we design biomimetic magnetically driven microrobots loaded with EB, which offer efficient motion control and drug delivery capabilities. In a mouse SCI model, the magnetic microrobot with macrophage membrane functionalized and EBs (MPE robot) actively target the injured area using rotating magnetic fields in the early stages of injury, modulated the local microglial phenotype to a neuroprotective state, inhibited local inflammation, and promote axon regeneration and neurological recovery. This approach demonstrates that a biomimetic microrobot loaded with EB offers an effective strategy for treating SCI and other central nervous system diseases.
Keywords: drug delivery; eleutheroside B; microrobots; neuroprotective immunity; spinal cord injury.