A Self-Powered Biosensor with a Flake Electrochromic Display for Electrochemical and Colorimetric Formaldehyde...

Area of Science:

• Electrochemistry
• Biosensors
• Environmental Science

Background:

• Formaldehyde detection requires cost-effective, specific, and simple methods for field use.
• Existing formaldehyde detection methods often lack the desired simplicity and cost-effectiveness for routine field applications.

Purpose of the Study:

• To develop a novel enzymatic self-powered biosensor (ESPB) for sensitive, rapid, and cost-effective formaldehyde detection.
• To enable both quantitative and qualitative formaldehyde detection through electrochemical and colorimetric readouts.

Main Methods:

• Fabrication of a bioanode using formaldehyde dehydrogenase, poly-methylene green, and buckypaper, and a cathode with Prussian blue, Au nanoparticles, and carbon fiber paper.
• Utilizing formaldehyde as fuel to drive the ESPB, measuring short-circuit current changes and observing cathode color transitions.
• Digital analysis of cathode color change using the B/(R + G + B) equation for precise quantification.

Main Results:

• Achieved a linear detection range of 0.01–0.35 mM formaldehyde with a detection limit of 0.006 mM via current measurement.
• Demonstrated naked-eye visual detection of formaldehyde up to 0.35 mM within 90 seconds, with digital quantification achieving 95–100% recovery in real water samples.
• Exhibited negligible interference from acetaldehyde and ethanol, and maintained over 92% performance after 21 days of storage at 4 °C.

Conclusions:

• The developed ESPB is a sensitive, simple, rapid, and cost-effective colorimetric tool for formaldehyde detection.
• The biosensor's design allows for both quantitative and qualitative analysis, suitable for environmental quality control and field monitoring.
• The ESPB offers a promising alternative to existing methods for routine and on-site formaldehyde screening.