Engineering Asymmetric and Highly Exposed Fe Single-Atom Nanozymes for siMMP13 Delivery and Ferroptosis Inhibition in Osteoarthritis Therapy

Adv Mater. 2026 Mar;38(16):e20951. doi: 10.1002/adma.202520951. Epub 2026 Feb 18.

Abstract

Ferroptosis, driven by redox imbalance, plays a critical role in osteoarthritis (OA) progression. Although antioxidant nanozymes hold therapeutic potential, designing highly efficient and targeted systems to inhibit ferroptosis remains challenging. Here, we developed a 2D nitrogen-doped graphene-like nanomesh (NGM) loaded with asymmetric and highly exposed Fe single atoms, carried with the cartilage-targeting WYRGRL peptide and siRNA (siMMP13) to form Fe SAzymes (si-FeSA/NGM-W) as ferroptosis inhibitors to alleviate OA. By mixed molten salt and Zn removal, exfoliating Zn-ZIF into an ultrathin 2D hierarchical porous NGM with topological defects and hierarchical structure, we created a scaffold for anchoring asymmetric and highly exposed Fe single atoms. The abundant Fe-N4-Cl coordination active sites then introduce strain and defects, which facilitate electron transfer, enhance radical adsorption, and lower reaction barriers, thereby augmenting multi-enzyme (SOD/CAT/GPx) activities. This enables the functionalized si-FeSA/NGM-W to target cartilage, where it inhibits ferroptosis by downregulating MMP13, upregulating GPX4, restoring mitochondrial function, and modulating inflammation, ultimately achieving targeted OA therapy. Mechanistically, this process involves suppression of the IL-17 pathway and enhancement of glutathione metabolism. This work presents a targeted nanozyme platform for precise OA therapy via ferroptosis inhibition.

Keywords: asymmetric and highly exposed; ferroptosis; nanozymes; osteoarthritis; siMMP13.

MeSH terms

  • Animals
  • Ferroptosis* / drug effects
  • Graphite / chemistry
  • Humans
  • Iron* / chemistry
  • Matrix Metalloproteinase 13 / genetics
  • Matrix Metalloproteinase 13 / metabolism
  • Mice
  • Osteoarthritis* / drug therapy
  • Osteoarthritis* / metabolism
  • Osteoarthritis* / pathology
  • RNA, Small Interfering* / chemistry

Substances

  • Iron
  • Graphite
  • RNA, Small Interfering
  • Matrix Metalloproteinase 13