Indicator Dyes and Catalytic Nanoparticles for Irreversible Visual Hydrogen Sensing.

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Developing noninvasive sensors for monitoring biomedical implants is crucial.
• Hydrogen (H2) gas is a byproduct of magnesium (Mg) implant biodegradation.
• Existing H2 detection methods lack the speed and visual feedback required for real-time monitoring.

Purpose of the Study:

• To identify an optimal indicator and bimetallic nanoparticle system for a visual H2 sensor.
• To develop a sensor for noninvasive monitoring of in vivo Mg-implant biodegradation.
• To achieve a fast response time for real-time H2 detection.

Main Methods:

• Utilized ultraviolet-visible (UV-vis) absorption spectroscopy to test indicator/Au-Pd NP systems.
• Evaluated bromothymol blue, methyl red, and resazurin as indicator molecules.
• Investigated the effect of H2, Au-Pd NPs, and indicator concentrations on response time.

Main Results:

• Bimetallic gold-palladium nanoparticles (Au-Pd NPs) catalyzed visual, irreversible color changes in indicators upon reaction with H2.
• The resazurin/Au-Pd NP system exhibited the fastest response to H2 at relevant biodegradation levels.
• Optimizing the ratio of resazurin to Au-Pd NPs allowed tuning of the color change response time.

Conclusions:

• The resazurin/Au-Pd NP system is a promising candidate for a wearable, visual H2 sensor.
• The sensor design is suitable for noninvasive monitoring of Mg-implant biodegradation.
• Further optimization of component concentrations can tailor sensor performance for specific applications.