Background-Free Imaging of Food Freshness Using Curcumin-Functionalized Upconversion Reversible Hydrogel Patch.

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Conventional optical labeling methods face limitations like background interference and spectral overlap.
• Functionalized upconversion nanomaterials offer an alternative with enhanced specificity and reduced interference.

Purpose of the Study:

• To develop a background-free and reversible upconversion hydrogel patch for sensitive food freshness monitoring.
• To utilize the patch for ultra-sensitive detection of biogenic amines.

Main Methods:

• Designing a curcumin-functionalized upconversion hydrogel patch for enhanced ductility and surface coverage.
• Employing fluorescence resonance energy transfer (FRET) triggered by biogenic amines to induce a color change in upconverted fluorescence.
• Integrating a smartphone color recognition system for quantitative analysis.

Main Results:

• The hydrogel patch demonstrated sensitive and reversible detection of biogenic amines with a low limit of detection (LOD) of 2.73 µm.
• The upconverted fluorescence shifted from green to red in the presence of biogenic amines.
• Quantitative analysis using a smartphone showed reliable results comparable to high-performance liquid chromatography (HPLC).

Conclusions:

• The developed hydrogel patch provides a practical and reliable method for real-time food freshness monitoring.
• This optical nano-sensing strategy shows significant potential for ensuring food safety and preventing spoilage.