Viral Mimicking Polyplexes as Hierarchical Unpacking Vectors for Rheumatoid Arthritis Treatment

Abstract Nano‐delivery systems hold great promise for the treatment of rheumatoid arthritis (RA). Current research efforts are primarily focused on enhancing their targeting capabilities and efficacy. Here, this study proposes a novel viral‐mimicking ternary polyplexes system for the controlled delivery of the anti‐inflammatory drug Cyclosporin A (CsA) to effectively treat RA. The ternary polyplexes consist of a nanogel core loaded with CsA and a hyaluronic acid shell, which facilitates CD44‐mediated targeting. By mimicking the Trojan Horse strategy employed by viruses, these polyplexes undergo a stepwise process of deshielding and disintegration within the inflamed joints. This process leads to the release of CsA within the cells and the scavenging of pathogenic factors. This study demonstrates that these viral‐mimicking ternary polyplexes exhibit rapid targeting, high accumulation, and prolonged persistence in the joints of RA mice. As a result, they effectively reduce inflammation and alleviate symptoms. These results highlight the potential of viral‐mimicking ternary polyplexes as a promising therapeutic approach for the targeted and programmed delivery of drugs to treat not only RA but also other autoimmune diseases.