Mesoporous polydopamine@CeO₂ nanoparticles for photoacoustic-guided photothermal therapy in suppressing arthritis

Rheumatoid arthritis (RA) is characterized by poor oxygen supply and overproduction of reactive oxygen species (ROS), thereby exacerbating synovial inflammation. We synthesized MPDA@CeO₂ nanoparticles (NPs) by incorporating mesoporous polydopamine (MPDA) NPs and CeO₂ for photoacoustic imaging (PAI)-guided synergistic light-controlled PTT/oxygen-boosting/ROS-eliminating therapy. Upon irradiation with a near-infrared (NIR) laser, MPDA@CeO₂ NPs trigger photothermal conversion to eradicate inflammatory cells and release CeO₂, which have a catalytic activity to eliminate ROS and release oxygen. The oxygen-release and ROS-depleting efficiency was simultaneously augmented by heat to further combat the harmful environment of inflammation. We validated the therapeutic effect of MPDA@CeO₂ in vitro and in vivo. We further applied multiwavelength PAI to observe the distribution of NPs and the change in oxygen saturation during the treatment process in vivo. The study highlights the therapeutic value of MPDA@CeO₂ in inhibiting arthritis in RA through imaging-guided synergistic therapy.