Hydrogen peroxide biosensor based on microperoxidase-11 immobilized in a silica cavity array electrode

Area of Science:

• Electrochemistry
• Biosensor Technology
• Materials Science

Background:

• Development of sensitive and stable biosensors is crucial for accurate hydrogen peroxide detection.
• Indium-doped tin oxide (ITO) electrodes offer good conductivity and surface properties for biosensor applications.
• Silica microcavity arrays can enhance electrochemical performance through confinement effects.

Purpose of the Study:

• To construct a novel hydrogen peroxide biosensor utilizing a silica cavity array modified ITO electrode.
• To investigate the electrochemical properties and performance of the fabricated biosensor.
• To explore the potential of this platform for detecting other enzymes.

Main Methods:

• Fabrication of silica microcavity arrays via electrodeposition using polystyrene particles as templates.
• Immobilization of microperoxidase-11 (MP-11) within the silica cavities.
• Electrochemical characterization using cyclic voltammetry and amperometry.
• Evaluation of analytical performance, including linear range, reproducibility, and stability.

Main Results:

• The silica cavity array created a confinement effect, enabling the electrode to function as "soft" microelectrodes.
• Immobilized MP-11 retained its physiological activity, facilitating electron transfer with the ITO electrode.
• The modified electrode exhibited quasi-reversible redox behavior with distinct peaks at -0.26 V and -0.15 V.
• High electrocatalytic activity towards hydrogen peroxide reduction was observed.
• Amperometric detection showed a linear range from 2×10⁻⁶ to 6×10⁻⁴ M for H2O2.
• The biosensor demonstrated good reproducibility and long-term stability.

Conclusions:

• The constructed hydrogen peroxide biosensor based on silica cavity array modified ITO electrode shows excellent performance.
• The unique structure provides an effective platform for enzyme immobilization and electron transfer.
• This novel biosensor offers a promising method for low-concentration hydrogen peroxide detection.
• The developed platform can be extended to create biosensors for various other enzymes.