Highly-Selective fluorescent Fe₃O₄@PPy aptasensor.

Area of Science:

• Analytical Chemistry
• Materials Science
• Biotechnology

Background:

• Label-free nucleic acid fluorescent probes offer cost-effective and simple detection methods.
• A major limitation is low specificity due to interactions with biomolecules like RNA, proteins, and enzymes.
• Developing highly selective and sensitive detection platforms remains a critical challenge.

Purpose of the Study:

• To develop a simple and highly selective detection platform using Fe3O4@PPy and label-free nucleic acid probes.
• To demonstrate the platform's versatility in detecting diverse targets including metal ions, acetamiprid, and thrombin.
• To validate the platform's performance in real-world clinical and environmental samples.

Main Methods:

• Fabrication of Fe3O4@PPy nanocomposites for adsorption and fluorescence quenching.
• Utilized label-free probes (TTAPE or Malachite Green) with aptamers for target recognition.
• Employed magnetic separation for target-analyte complex isolation and fluorescence recovery.

Main Results:

• The Fe3O4@PPy platform demonstrated high selectivity for metal ions, acetamiprid, and thrombin.
• Photoluminescence emission intensity showed a linear response to target concentrations.
• Achieved low limits of detection in real samples: 0.02 ng/L for acetamiprid, 4.3 nM for thrombin, and 0.17 nM for Pb2+.

Conclusions:

• The Fe3O4@PPy aptasensor provides a robust and universal platform for sensitive and selective detection.
• The method overcomes specificity issues associated with traditional label-free probes.
• Potential for widespread application in clinical diagnostics and environmental monitoring.