Laser-assisted thermoelectric-enhanced hydrogen peroxide biosensors based on Ag₂Se nanofilms for sensitive detection...

Thermoelectric (TE) materials can convert the heat produced during biochemical reactions into electrical signals, enabling the self-powered detection of biomarkers. In this work, we design and fabricate a simple Ag₂Se nanofilm-based TE biosensor to precisely quantify hydrogen peroxide (H₂O₂) levels in liquid samples. A chemical reaction involving horseradish peroxidase, ABTS and H₂O₂ in the specimens produces a photothermal agent-ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) free radical, which triggers the heat fluctuations at the TE sensor through the photo-thermal effect, eventually enabling the sensing of H₂O₂. Consequently, the constructed sensor can achieve a detection limit of 0.26 μM by a three-leg TE device design. Further investigations suggest that the application of our TE sensor can be extended in testing H₂O₂ in beverages (including milk, soda water, and lemonade) and evaluating the load of bacterial pathogens relevant to dental diseases and infections including Streptococcus sanguinis and Methicillin-resistant Staphylococcus aureus with high analytical accuracy. This strategy utilizes the combination of high thermoelectric performance with chemical reactions to realize a straightforward and accurate biomarker detection method, making it suitable for applications in medical diagnostics, personalized health monitoring, and the food industry.