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 <i>in vitro</i> and <i>in vivo</i>. We further applied multiwavelength PAI to observe the distribution of NPs and the change in oxygen saturation during the treatment process <i>in vivo</i>. The study highlights the therapeutic value of MPDA@CeO₂ in inhibiting arthritis in RA through imaging-guided synergistic therapy.