Colorimetric biosensors based on DNAzyme-assembled gold nanoparticles

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Recent advancements in nanoparticle-based colorimetric detection and in vitro selection of functional nucleic acids have enabled novel biosensor designs.
• Functional DNA/RNA can be selected to recognize a wide range of analytes, paving the way for versatile biosensing applications.

Purpose of the Study:

• To design highly sensitive and selective colorimetric biosensors for various analytes.
• To demonstrate a DNAzyme-directed assembly strategy for gold nanoparticles as an example of sensor design.
• To explore the potential of allosteric DNA/RNAzymes for expanding nanoparticle-based sensor capabilities.

Main Methods:

• Utilized DNAzyme-directed assembly of gold nanoparticles for colorimetric detection.
• Employed a DNAzyme composed of an enzyme and substrate strand to control nanoparticle aggregation.
• Investigated the color change from blue (aggregated nanoparticles) to red (disassembled nanoparticles) in the presence of lead.

Main Results:

• Developed a highly sensitive and selective colorimetric lead biosensor.
• Demonstrated the disruption of gold nanoparticle assembly by lead-induced DNAzyme activity, leading to a distinct color change.
• Successfully applied the sensor for lead detection in leaded paint samples.

Conclusions:

• The DNAzyme-directed assembly of gold nanoparticles provides a robust platform for sensitive and selective colorimetric biosensing.
• This method offers a versatile approach for detecting various analytes by designing specific DNAzymes.
• Future applications may involve allosteric DNA/RNAzymes to further enhance the sensor design and analyte detection range.