Microvesicle-camouflaged biomimetic nanoparticles encapsulating a metal-organic framework for targeted rheumatoid arthritis therapy

Background: Methotrexate (MTX) has been highlighted for Rheumatoid arthritis (RA) treatment, however, MTX does not accumulate well at inflamed sites, and long-term administration in high doses leads to severe side effects. In this study, a novel anti-RA nanoparticle complex was designed and constructed, which could improve the targeted accumulation in inflamed joints and reduce side effects.

Results: Here, we prepared a pH-sensitive biomimetic drug delivery system based on macrophage-derived microvesicle (MV)-coated zeolitic imidazolate framework-8 nanoparticles that encapsulated the drug methotrexate (hereafter MV/MTX@ZIF-8). The MV/MTX@ZIF-8 nanoparticles were further modified with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[folate (polyethylene glycol)-2000] (hereafter FPD/MV/MTX@ZIF-8) to exploit the high affinity of folate receptor β for folic acid on the surface of activated macrophages in RA. MTX@ZIF-8 nanoparticles showed high DLE (~ 70%) and EE (~ 82%). In vitro study showed that effective drug release in an acidic environment could be achieved. Further, we confirmed the activated macrophage could uptake much more FPD/MV/MTX@ZIF-8 than inactivated cells. In vivo biodistribution experiment displayed FPD/MV/MTX@ZIF-8 nanoparticles showed the longest circulation time and best joint targeting. Furthermore, pharmacodynamic experiments confirmed that FPD/MV/MTX@ZIF-8 showed sufficient therapeutic efficacy and safety to explore clinical applications.

Conclusions: This study provides a novel approach for the development of biocompatible drug-encapsulating nanomaterials based on MV-coated metal-organic frameworks for effective RA treatment.