An Edible H₂O₂ Biosensor for Gastrointestinal Metabolites and Peroxidase Enzyme Quantification

Area of Science:

• Biomedical Engineering
• Gastroenterology
• Sensor Technology

Background:

• Gastrointestinal (GI) fluid analysis is crucial for diagnostics but limited by conventional ingestible devices' rigidity, toxicity, and environmental impact.
• Existing methods require specialized clinical settings, hindering point-of-care accessibility.
• There is a need for safe, biocompatible, and environmentally friendly ingestible biosensors.

Purpose of the Study:

• To develop and validate an edible biosensor for quantifying metabolites and enzyme activity in gastric fluid.
• To demonstrate the biosensor's safety through ingestibility and partial metabolism post-use.
• To enable direct in vivo biosensing for the GI tract.

Main Methods:

• An edible biosensor was designed using a redox reaction involving caffeic acid and horseradish peroxidase for hydrogen peroxide (H2O2) quantification.
• The sensing system was integrated into an edible extended-gate electrolyte-gated field-effect transistor utilizing a toothpaste pigment as the semiconductor.
• Spectrophotometric, electrochemical, and in vitro validation methods were employed, including testing in a simulated physiological environment.

Main Results:

• The edible biosensor successfully quantified H2O2, a marker for GI inflammation, in the 0-3 mM range with a limit of detection of approximately 143.7 µM.
• The device demonstrated a sensitivity of 2.7 µC mM-1 for H2O2 detection.
• Proof-of-application showed the biosensor's adaptability for detecting glucose, cholesterol, and gastric peroxide enzyme activity with minimal modifications.

Conclusions:

• The developed edible biosensor offers a safe, accessible, and environmentally conscious approach for GI fluid analysis.
• This technology advances in vivo biosensing capabilities, enabling point-of-care diagnostics directly within the gastrointestinal tract.
• The edible biosensor platform holds significant potential for personalized medicine and early detection of GI diseases.