Size Effect in Pd-Ir Core-Shell Nanoparticles as Nanozymes.

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Nanozymes, nanomaterials with enzyme-like activities, offer promising catalytic properties.
• Comprehensive studies on the size-dependent catalytic effects in nanozymes are limited.
• Understanding size effects is crucial for optimizing nanozyme applications.

Purpose of the Study:

• To systematically investigate the influence of size on the catalytic activity and biosensing performance of nanozymes.
• To utilize palladium-iridium (Pd-Ir) core-shell nanoparticles as a model system to study size effects.
• To correlate nanozyme size with performance in enzyme-linked immunosorbent assay (ELISA) platforms.

Main Methods:

• Synthesis of Pd-Ir core-shell nanoparticles with controlled sizes (3.3, 5.9, 9.8, and 13.0 nm).
• Characterization of nanoparticles to ensure identical shapes and surface structures across different sizes.
• Evaluation of peroxidase-like catalytic activity of nanozymes.
• Assessment of nanozyme performance in an ELISA platform to determine detection limits.

Main Results:

• Individual nanozyme catalytic activity increased with particle size.
• Area-specific catalytic activity remained consistent for nanoparticles up to 9.8 nm, with a slight decrease at 13.0 nm.
• Smaller Pd-Ir nanoparticles demonstrated lower detection limits in ELISA-based biosensing applications.

Conclusions:

• Nanozyme performance is significantly influenced by particle size.
• Catalytic activity generally increases with size, while biosensing sensitivity is enhanced by smaller nanoparticles.
• This research provides insights into optimizing nanozyme design for specific catalytic and biosensing applications.