Multifunctional platinum-tellurium nanorods modified with hyaluronic acid remove reactive oxygen species to improve the photothermal treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, in which inflammatory macrophages play a crucial role by secreting a large number of proinflammatory factors to aggravate inflammatory response. In addition, reactive oxygen species (ROS) are abundant in hypoxic joints, inducing chondrocyte apoptosis and causing irreversible bone destruction. In this work, we synthesized hyaluronic acid-modified platinum-tellurium nanorods (HPT) as a photothermal agent to target RA joints, ablating inflammatory macrophages and scavenging ROS in the microenvironment. Hyaluronic acid can specifically bind to the CD44 receptors, which are over-expressed on the surface of inflammatory macrophages, achieving active targeting and improving therapy effectiveness. Under the irradiation of an 808 nm laser, thermal energy produced by HPT, which has high photothermal conversion ef-ficiency is sufficient to induce apoptosis of inflammatory macrophages. Simultaneously, platinum particles on the surface of tellurium nanorods can effectively remove a variety of ROS, reducing oxidative stress and alleviating inflammatory response in RA joints. Collagen-induced arthritis (CIA) mice had been used to study the therapeutic potential of HPT. The results revealed that the clinical scores in CIA mice injected with HPT and irradiated with a near-infrared laser were significantly reduced. The inflammatory response was also obviously relieved, when compared with CIA mice injected with PBS. Micro-CT imaging revealed that bone erosion was visibly reduced in the HPT + Laser group. These results demonstrate that multifunctional HPT is promising to serve as a therapeutic platform for the treatment of RA.