Ultra-Small Iron-Based Nanoparticles with Mild Photothermal-Enhanced Cascade Enzyme-Mimic Reactions for Tumor Therapy

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Oncology

Background:

• Chemodynamic therapy (CDT) shows promise for cancer treatment but is limited by low hydrogen peroxide (H₂O₂) levels and poor enzyme activity in tumors.
• Existing nanoparticle catalysts often struggle with insufficient substrate availability and suboptimal reaction rates.

Purpose of the Study:

• To engineer ultra-small iron-based (USIB) nanoparticles with dual superoxide dismutase (SOD)-mimic and peroxidase (POD)-mimic activities.
• To enhance the efficacy of chemodynamic therapy by overcoming substrate limitations and improving catalytic efficiency.

Main Methods:

• USIB nanoparticles were synthesized with cascaded SOD-mimic and POD-mimic activities.
• SOD-mimic activity converted superoxide anions to H₂O₂, increasing local H₂O₂ concentration.
• POD-mimic activity converted H₂O₂ to hydroxyl radicals (·OH) for tumor cell destruction.
• Photothermal conversion capabilities and laser irradiation effects on enzymatic activity were investigated.

Main Results:

• USIB nanoparticles successfully elevated H₂O₂ levels in the tumor microenvironment.
• The nanoparticles effectively converted H₂O₂ into highly reactive ·OH radicals.
• Enzymatic activity and therapeutic efficacy were significantly enhanced by mild laser irradiation.
• The treatment demonstrated effective tumor growth inhibition and excellent biosafety.

Conclusions:

• The developed USIB nanoparticles overcome key limitations of traditional chemodynamic therapy.
• The integration of cascade nanozyme reactions with laser irradiation offers a potent strategy for cancer treatment.
• This approach presents a promising therapeutic potential with significant improvements in efficacy and biosafety.