Polyethyleneimine-templated copper nanoclusters via ascorbic acid reduction approach as ferric ion sensor

Area of Science:

• Nanomaterials Science
• Analytical Chemistry
• Biomedical Engineering

Background:

• Fluorescent probes are crucial for detecting metal ions.
• Developing stable, water-soluble fluorescent nanomaterials remains a challenge.
• Sensitive detection of ferric ions (Fe3+) is important for environmental and health monitoring.

Purpose of the Study:

• To develop a facile one-pot method for synthesizing water-soluble and stable fluorescent copper nanoclusters (CuNCs).
• To utilize the synthesized BPEI-CuNCs as a sensitive fluorescence probe for detecting ferric ions (Fe3+).

Main Methods:

• Synthesis of fluorescent copper nanoclusters (CuNCs) using branched polyethyleneimine (BPEI) as a capping agent and ascorbic acid as a reducing agent at room temperature.
• Characterization of BPEI-CuNCs for properties like water-solubility, photostability, and stability in high ionic strength solutions.
• Development of a fluorescence quenching-based assay for Fe3+ detection utilizing an electron transfer mechanism.

Main Results:

• Successfully synthesized water-soluble and stable fluorescent BPEI-CuNCs via a one-pot method.
• BPEI-CuNCs demonstrated excellent water-solubility, photostability, and high stability in solutions with high ionic strength.
• The fluorescence probe exhibited sensitive and selective detection of Fe3+ with a limit of detection of 340 nM.
• The method's detection limit for Fe3+ is below the US EPA permissible level in drinking water.
• Successful application in detecting Fe3+ in real-world samples including tap water, Yellow River water, and human urine, with high spike recovery rates (95.3%–112.0%).

Conclusions:

• A facile and efficient one-pot method for synthesizing stable, water-soluble fluorescent BPEI-CuNCs was established.
• The developed BPEI-CuNCs serve as a highly sensitive and selective fluorescence probe for Fe3+ detection.
• This method offers a promising tool for monitoring Fe3+ in environmental and biological samples.