Magnesium-Based Micromotors as Hydrogen Generators for Precise Rheumatoid Arthritis Therapy.

Hydrogen therapy is an emerging and highly promising strategy for the treatment of inflammation-related diseases. However, nonpolarity and low solubility of hydrogen under the physiological conditions results in a limited therapeutic effect. Herein, we develop a biocompatible magnesium micromotor coated with hyaluronic acid as a hydrogen generator for precise rheumatoid arthritis management. The hydrogen bubbles generated locally not only function as a propellant for the motion but also function as the active ingredient for reactive oxygen species (ROS) and inflammation scavenging. Under ultrasound guidance, the micromotors are injected intra-articularly, and the dynamics of the micromotors can be visualized. By scavenging ROS and inflammation via active hydrogen, the oxidative stress is relieved and the levels of inflammation cytokines are reduced by our micromotors, showing prominent therapeutic efficacy in ameliorating joint damage and suppressing the overall arthritis severity toward a collagen-induced arthritis rat model. Therefore, our micromotors show great potential for the therapy of rheumatoid arthritis and further clinical transformation.