Comparative quantification of nucleic acids using single-molecule detection and molecular beacons.

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• Conventional nucleic acid quantification methods often suffer from limited sensitivity and high reagent consumption.
• Dual-color ensemble measurements can be complicated by fluorescent variability, impacting accuracy.
• There is a need for highly sensitive, amplification-free methods for comparative nucleic acid quantification.

Purpose of the Study:

• To develop and validate a highly sensitive homogenous method for comparative quantification of nucleic acids.
• To utilize single-molecule detection (SMD) with molecular beacons (MBs) for simultaneous detection of target and control strands.
• To achieve superior performance compared to conventional ensemble methods.

Main Methods:

• Employed two spectrally distinct molecular beacons (MBs) for a separation-free comparative hybridization assay.
• Utilized single-molecule fluorescence spectroscopy to detect fluorescent bursts from single nucleic acid hybrids.
• Quantified targets by counting discrete fluorescent bursts with high signal-to-noise ratio (SNR).

Main Results:

• Achieved a detection limit improvement of 3 orders of magnitude compared to ensemble methods.
• Reduced probe consumption by 6 orders of magnitude.
• Demonstrated high SNR in both detection channels, overcoming fluorescent variability issues.

Conclusions:

• The developed homogenous method offers a highly sensitive approach for comparative nucleic acid quantification.
• Single-molecule detection with molecular beacons provides a promising platform for amplification-free genomic quantification.
• This technique significantly enhances sensitivity and reduces reagent requirements for nucleic acid analysis.