Dynamic-light-scattering-based sequence-specific recognition of double-stranded DNA with...

Area of Science:

• Nanotechnology
• Biochemistry
• Analytical Chemistry

Background:

• Accurate detection of specific DNA sequences is crucial for diagnostics and research.
• Existing methods for DNA detection can be complex or lack sensitivity.
• Gold nanoparticles (AuNPs) offer unique optical properties for biosensing applications.

Purpose of the Study:

• To develop a highly sensitive and sequence-specific assay for double-stranded DNA (dsDNA) detection.
• To utilize dynamic-light-scattering (DLS) for quantifying dsDNA based on nanoparticle aggregation.
• To establish a simple and efficient method for DNA sequence recognition.

Main Methods:

• Designed and synthesized AuNP probes functionalized with specific oligonucleotide sequences (Oligo 1 and Oligo 2).
• Utilized a target dsDNA composed of complementary oligonucleotides (Oligo 3 and Oligo 4).
• Applied dynamic-light-scattering (DLS) to measure the change in average diameter of AuNP probes upon hybridization with target dsDNA, forming triplex DNA and inducing aggregation.

Main Results:

• The assay demonstrated sequence-specific recognition of the target dsDNA.
• AuNP aggregation, indicated by increased average diameter, was directly proportional to target dsDNA concentration.
• Achieved an ultrasensitive detection limit of 593 fM for dsDNA over a concentration range from 593 fM to 40 pM.

Conclusions:

• The developed DLS assay provides a simple, ultrasensitive, and sequence-specific method for dsDNA detection.
• This approach holds promise for various applications requiring precise DNA quantification.
• The use of AuNP probes and DLS offers a robust platform for nucleic acid sensing.