Bimetallic oxide (CoNi₂O₄) nanozyme as ROS independent for ascorbic acid detection with computational study

Area of Science:

• Materials Science
• Nanotechnology
• Biochemistry

Background:

• Enzyme mimic catalysts offer alternatives to natural enzymes.
• Developing robust and sensitive biosensors is crucial for diagnostics.

Purpose of the Study:

• Synthesize spinel cobalt nickel oxide nanoflowers (CoNi2O4 NFs).
• Investigate their enzyme mimic activities, specifically oxidase-like behavior.
• Develop a colorimetric biosensor for ascorbic acid (AA) detection.

Main Methods:

• Two-step hydrothermal annealing for material synthesis.
• Enzyme kinetics studies (Michaelis-Menten equation).
• Density Functional Theory (DFT) and molecular modeling (MD) for mechanism elucidation.
• Colorimetric detection of ascorbic acid.

Main Results:

• CoNi2O4 NFs exhibit intrinsic oxidase-like activity, oxidizing TMB.
• Catalytic activity follows Michaelis-Menten kinetics with a low Km (0.0143 mM).
• Developed a highly sensitive and selective colorimetric biosensor for AA (LOD = 0.44 μM).
• Demonstrated feasibility in detecting AA in vitamin C capsules and lemon fruit.

Conclusions:

• Spinel CoNi2O4 NFs possess significant enzyme mimic capabilities.
• The developed biosensor is stable, selective, and sensitive for AA detection.
• DFT calculations reveal the catalytic mechanism involving cobalt sites and TMB's amine group.