Oxygen Vacancy-Enriched Platinum Single-Atom Nanozyme Wrapped in Nanoislands: Unlocking Catalytic Activity and...

Area of Science:

• Biomaterials Science
• Nanotechnology
• Orthopedics

Background:

• Steroid-induced osteonecrosis of the femoral head (SONFH) involves impaired bone regeneration due to excessive reactive oxygen species (ROS).
• Current antioxidant therapies for SONFH have limitations in catalytic efficiency and duration.
• Single-atom nanozymes (SANs) offer potential but face challenges with high energy barriers in ROS catalysis.

Purpose of the Study:

• To develop a highly efficient single-atom nanozyme for treating SONFH.
• To investigate the synergistic effects of platinum (Pt) single atoms embedded in CeO2-x for enhanced catalytic activity.
• To explore the therapeutic potential of the novel nanozyme in a preclinical SONFH model.

Main Methods:

• Synthesis of CeO2-x/Pt single-atom nanozyme (SANI) with an "island-sea" structure.
• Characterization of nanozyme properties and catalytic activity using density functional theory (DFT) calculations.
• Evaluation of therapeutic efficacy in a SONFH model using single-cell sequencing and experimental validation.

Main Results:

• CeO2-x/Pt SANI demonstrated enhanced catalytic activity and ROS scavenging compared to CeO2 alone, attributed to the "island-sea" synergistic effect.
• DFT calculations confirmed improved ROS adsorption and redox reaction acceleration due to Pt incorporation and increased oxygen vacancies.
• The nanozyme successfully reprogrammed the oxidative microenvironment, leading to significant therapeutic effects in SONFH models.

Conclusions:

• The "island-sea" structured CeO2-x/Pt SANI exhibits superior catalytic performance for ROS mitigation.
• This nanozyme holds significant therapeutic promise for treating SONFH by restoring bone regeneration and angiogenesis.
• The study provides a rational design strategy for advanced single-atom nanozymes with optimized catalytic activity.