PBA-Derived Heteroatom-Doped Mesoporous Graphitic Spheroids as Peroxidase Nanozyme for In Vitro Tumor Cells Detection

Area of Science:

• Biomimetic catalysis
• Nanomaterials
• Heterogeneous catalysis

Background:

• Natural peroxidases (POD) utilize vanadium or heme (iron) active centers.
• Co-doping graphene with heteroatoms enhances catalytic properties by reducing substrate migration distances.
• Synthesizing heterometallic co-doped graphene is challenging due to complex procedures.

Purpose of the Study:

• To develop a novel dual metal-based nanozyme with dual vanadium (V) and iron (Fe)-based active catalytic centers.
• To synthesize V and Fe co-doped mesoporous graphitic spheroids (VNFe@C) using a template-free pyrolysis method.
• To evaluate the nanozyme's peroxidase-like activity and its application in detecting tumor cells.

Main Methods:

• Synthesized a Prussian-blue analog precursor via a facile one-step, low-temperature method.
• Prepared VNFe@C mesoporous graphitic spheroids through pyrolysis without template assistance.
• Assessed the nanozyme's affinity for hydrogen peroxide (H₂O₂) and its peroxidase-like activity, including reactive oxygen species generation.

Main Results:

• The synthesized VNFe@C nanozyme exhibited excellent affinity for H₂O₂, with a Michaelis constant (K<0xE2><0x82><0x98>) of 0.26 mM, outperforming natural POD (0.436 mM).
• The nanozyme demonstrated effective in vitro detection of tumor cells by sensing intracellular H₂O₂.
• VNFe@C generated dual reactive oxygen species (•OH and •O₂H⁻), confirming its POD-like activity, with synergistic enhancement from V/Fe co-doping.

Conclusions:

• A novel, template-free method successfully synthesized dual V/Fe-based nanozymes (VNFe@C) with enhanced peroxidase-like activity.
• The bimetallic nanozyme shows superior H₂O₂ affinity and potential for sensitive tumor cell detection.
• Synergistic effects of V and Fe co-doping in graphitic spheroids significantly boost catalytic performance.