Cationic-perylene-G-quadruplex complex based fluorescent biosensor for label-free detection of Pb(2+)

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Lead ions (Pb2+) are toxic environmental pollutants.
• Accurate detection of Pb2+ is crucial for environmental and health monitoring.
• Existing detection methods can be complex or require labeling.

Purpose of the Study:

• To develop a simple, rapid, and label-free fluorescent biosensor for Pb2+ detection.
• To utilize a water-soluble cationic perylene derivative as a G-quadruplex (G4) structure fluorescence indicator.
• To achieve selective and sensitive quantification of Pb2+.

Main Methods:

• Construction of a fluorescent biosensor using a perylene derivative (compound 1) and a G-rich DNA probe (PW17).
• Exploitation of Pb2+-induced G4 structure formation to modulate fluorescence.
• Development of a "mix-and-detect" protocol for quantitative analysis.

Main Results:

• The biosensor demonstrated high fluorescence in the presence of Pb2+ due to the formation of Pb2+-stabilized G4 structures.
• Achieved high selectivity for Pb2+ by leveraging the specific DNA folding induced by Pb2+.
• Exhibited high sensitivity with a limit of detection of 5.0 nM for Pb2+.
• Successfully applied the biosensor for Pb2+ detection in real-world samples like urine and paint.

Conclusions:

• The developed fluorescent biosensor offers a promising platform for simple, rapid, label-free, selective, and sensitive detection of Pb2+.
• The biosensor's applicability in real samples highlights its practical potential for environmental and health monitoring.
• This approach provides an efficient strategy for developing G4-based fluorescent biosensors for heavy metal ion detection.