Portable Enzyme-Paper Biosensors Based on Redox-Active CeO2 Nanoparticles

Area of Science:

• Biosensing
• Nanotechnology
• Analytical Chemistry

Background:

• Nanoparticle (NP)-enhanced enzyme sensors are vital for analyzing diverse analytes in biomedicine, environmental science, and pharmaceuticals.
• Current methods often rely on peroxidases, which can be avoided with alternative sensing platforms.

Purpose of the Study:

• To describe the fabrication of a portable, paper-based, inexpensive, and robust enzyme biosensor.
• To detect substrates of oxidase enzymes using a novel sensing platform.
• To avoid the use of peroxidases in enzyme-based detection methods.

Main Methods:

• Utilized redox-active cerium oxide (CeO2) nanoparticles (NPs) as a sensing platform.
• CeO2 NPs act as both enzyme supports and color-generating reagents in response to H2O2.
• Developed a paper-based sensor with embedded reagents for ease of use and storage.

Main Results:

• The CeO2 NP-based sensor produces a colorimetric response for oxidase enzyme substrates.
• The sensor demonstrated dual functionality: high surface area for enzyme loading and color generation.
• The biosensor is reusable, disposable, inexpensive, and can be mass-produced using printing methods.
• Sensors showed stability over extended storage periods without performance degradation.

Conclusions:

• Developed a general, portable, and cost-effective enzyme biosensor platform for oxidase enzyme substrates.
• The CeO2 NP-based sensor offers a robust and reusable alternative to traditional methods.
• This technology is suitable for in-field detection in clinical, food, and environmental samples.