A Novel Fluorescent Biosensor for Detection of Silver Ions Based on Upconversion Nanoparticles

Area of Science:

• Nanomaterials Science
• Analytical Chemistry
• Biomedical Engineering

Background:

• Silver ions (Ag+) are significant environmental pollutants and have biological implications.
• Accurate detection of Ag+ is crucial for environmental monitoring and healthcare.
• Existing detection methods may lack sensitivity, selectivity, or simplicity.

Purpose of the Study:

• To develop a simple, sensitive, and selective fluorescent biosensor for quantitative Ag+ analysis.
• To utilize NaYF4:Yb3+, Tm3+ upconversion nanoparticles (UCNPs) as a core detection platform.
• To demonstrate the potential for real-world sample analysis.

Main Methods:

• Synthesis and characterization of NaYF4:Yb3+, Tm3+ UCNPs.
• Development of a fluorescence quenching assay based on Ag+-mediated oxidation of o-phenylenediamine (OPD).
• Investigation of inner filter effects (IFE) between UCNPs and oxidized OPD (oxOPD).

Main Results:

• The fluorescence intensity of UCNPs was significantly quenched by oxOPD, with quenching efficiency proportional to Ag+ concentration.
• The biosensor achieved quantitative detection of Ag+ in the range of 0 to 0.5 mM.
• A low detection limit of 33 nM for Ag+ was obtained under optimized conditions.
• The method demonstrated high selectivity and sensitivity, with potential for interference-free detection in real samples.

Conclusions:

• A novel and effective fluorescent biosensor for Ag+ detection was successfully developed using UCNPs.
• The proposed method offers a simple, sensitive, and selective approach for Ag+ quantification.
• The biosensor shows promise for practical applications in environmental and biological sample analysis.