DNAzyme Based Amplified Biosensor on Ultrasensitive Fluorescence Detection of Pb (II) Ions from Aqueous System

Area of Science:

• Analytical Chemistry
• Environmental Science
• Biotechnology

Background:

• Lead(II) ions (Pb2+) pose significant environmental and health risks.
• Accurate detection of Pb2+ is crucial for environmental monitoring and public health.
• Existing biosensors often require labels, increasing complexity and cost.

Purpose of the Study:

• To develop a highly selective and sensitive label-free fluorescent biosensor for Pb2+ detection.
• To utilize DNAzyme amplification for enhanced signal generation.
• To demonstrate the biosensor's applicability in real environmental water samples.

Main Methods:

• Design of a DNAzyme complex through hybridization of enzyme and substrate strands.
• Pb2+-mediated cleavage of the substrate strand, releasing a fragment.
• Hybridization of the released fragment with a complementary strand on magnetic beads (MBs).
• Fluorescence detection using SYBR Green I intercalation with the resulting double-stranded DNA (dsDNA).

Main Results:

• The label-free DNAzyme biosensor exhibited high selectivity and sensitivity for Pb2+.
• A low detection limit of 5 nM for Pb2+ was achieved within a detection range of 0-500 nM.
• The biosensor was successfully applied to determine Pb2+ concentrations in environmental water samples.

Conclusions:

• The developed label-free fluorescent biosensor offers a convenient and sensitive method for Pb2+ quantification.
• This approach holds potential for real-time monitoring in biological and environmental fields.
• The DNAzyme amplification strategy enhances the biosensor's performance.