Hyaluronic acid-based M1 macrophage targeting and environmental responsive drug releasing nanoparticle for enhanced treatment of rheumatoid arthritis

Herein, hyaluronic acid (HA) and β-cyclodextrin (β-CD) is used to form targeted drug delivery platform HCPC/DEX NPs with previously prepared carbon dots (CDs) as cross-linker, dexamethasone (DEX) is loaded for rheumatoid arthritis (RA) treatment. The drug loading capacity of β-CD and M1 macrophage targeting of HA were utilized for efficient delivery of DEX to the inflammatory joints. Because of the environmental responsive degradation of HA, DEX can be released in 24 h and inhibit the inflammatory response in M1 macrophages. The drug loading of NPs is 4.79 %. Cellular uptake evaluation confirmed that NPs can specifically target to M1 macrophages via HA ligands, the uptake of M1 macrophages is 3.7 times that of normal macrophages. In vivo experiments revealed that NPs can accumulate in RA joints to alleviate inflammation and accelerate cartilage healing, the accumulation can be observed in 24 h. The cartilage thickness increased to 0.45 mm after HCPC/DEX NPs treatment, indicating its good RA therapeutic effect. Importantly, this study was the first to utilize the potential acid and reactive oxygen species responsiveness of HA to release drug and prepare M1 macrophage targeting nanodrug for RA treatment, which provides a safe and effective RA therapeutic strategy.