Antioxidative and Robust Fluorescent Hydrogel for Deep Learning-Assisted Non-Destructive Detection of Hg²

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Flexible fluorescent hydrogels are promising for heavy-metal sensing but face challenges with stability in oxidative environments and reliable fluorescence signaling.
• Existing materials often exhibit a trade-off between strong fluorescence and robustness or adhesion.

Purpose of the Study:

• To develop a novel hydrogel that overcomes the limitations of current flexible fluorescent sensors for heavy-metal detection.
• To create a sensor with high mechanical flexibility, underwater adhesion, stable fluorescence, and antioxidative properties.

Main Methods:

• Fabrication of phycocyanin-polyacrylamide (PC-PAAM) hydrogel.
• Utilizing phycocyanin (PC) as both a fluorescent cross-linker and reactive oxygen species (ROS)-scavenging component.
• Developing a deep-learning model for image-based quantification of Hg2+.

Main Results:

• The PC-PAAM hydrogel demonstrated high mechanical flexibility, strong underwater adhesion, and stable red fluorescence.
• The sensor achieved a low detection limit of 6.21 nM for Hg2+ with rapid fluorescence quenching upon coordination.
• The hydrogel enabled conformal contact for nondestructive detection on biological surfaces like fish.
• Smartphone imaging coupled with a deep-learning model allowed for accurate and portable quantification of Hg2+.

Conclusions:

• The developed PC-PAAM hydrogel effectively resolves the trade-off between fluorescence signaling and material stability.
• This intelligent sensing platform offers a flexible, adhesive, and robust solution for environmental and food-safety monitoring of heavy metals.
• The system provides a practical approach for on-site, visual, and quantitative detection of mercury contamination.