A novel method to construct a third-generation biosensor: self-assembling gold nanoparticles on thiol-functionalized...

Area of Science:

• Nanotechnology
• Biochemistry
• Electrochemistry

Background:

• Horseradish peroxidase (HRP) is crucial for biosensing applications.
• Developing efficient and stable HRP biosensors is an ongoing research area.
• Nanomaterials offer unique properties for biosensor fabrication.

Purpose of the Study:

• To develop a novel horseradish peroxidase (HRP) biosensor.
• To utilize self-assembled gold nanoparticles on functionalized nanospheres for HRP immobilization.
• To evaluate the performance of the fabricated HRP biosensor for hydrogen peroxide detection.

Main Methods:

• Fabrication of thiol-functionalized poly(styrene-co-acrylic acid) (St-co-AA) nanospheres via emulsifier-free emulsion polymerization.
• Self-assembly of gold nanoparticles onto the functionalized nanospheres via chemisorption.
• Immobilization of HRP onto the gold nanoparticle surface.
• Electrochemical characterization of the HRP biosensor for hydrogen peroxide reduction.

Main Results:

• The HRP biosensor demonstrated an excellent electrocatalytic response to H2O2 reduction without an electron mediator.
• High sensitivity was achieved with a detection limit of 4.0 µmol/L and a linear range from 10.0 µmol/L to 7.0 mmol/L.
• The biosensor maintained over 97.8% of its activity after 60 days, showing excellent stability.
• Good current repeatability and fabrication reproducibility were observed.

Conclusions:

• A novel and efficient HRP biosensor was successfully fabricated using self-assembled gold nanoparticles on functionalized nanospheres.
• The developed biosensor is highly sensitive, stable, and reproducible for hydrogen peroxide detection.
• This mediator-free approach offers a promising platform for electrochemical HRP-based biosensing applications.