Solid-phase colorimetric sensing probe for bromide based on a tough hydrogel embedded with silver nanoprisms.

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Sharp-tipped anisotropic silver (Ag) nanostructures possess unique optical properties but are thermodynamically unstable in solution, limiting their use in sensing.
• Aggregation and transformation of Ag nanostructures in solution hinder their application in colorimetric sensing.

Purpose of the Study:

• To develop a stable, solid-phase colorimetric sensing platform for detecting bromide (Br-) in aqueous media.
• To leverage the localized surface plasmon resonance (LSPR) properties of Ag nanoprisms for sensitive and selective Br- detection.

Main Methods:

• Synthesis of a tough hydrogel with interpenetrating polymer networks embedding Ag nanoprisms via aqueous-phase polymerization.
• Immobilization of Ag nanoprisms within the hydrogel to prevent aggregation and degradation, maintaining LSPR properties upon drying.
• Utilizing the morphological transformation of Ag nanoprisms upon exposure to Br- and subsequent LSPR changes for detection.

Main Results:

• The Ag-nanoprism-embedded hydrogel provided a stable solid-phase platform, preserving nanoprism integrity and LSPR properties.
• The sensing platform demonstrated sensitive and selective detection of Br- in aqueous solutions.
• A low limit of detection (LOD) of 10 μM was achieved, with a wide sensing range.

Conclusions:

• The developed hydrogel-based sensing platform offers a stable, portable, eco-friendly, and safe method for naked-eye detection of Br-.
• The platform's stability and ease of use make it suitable for point-of-care analytical applications.
• This approach overcomes the limitations of solution-based sensing with unstable anisotropic nanostructures.