High-resolution capillary electrophoretic analysis of DNA in free solution

Area of Science:

• Analytical Chemistry
• Molecular Biology
• Biochemistry

Background:

• Traditional DNA fragment analysis can be time-consuming.
• Optimizing separation conditions is crucial for high-resolution DNA analysis.
• Accurate quantitation of amplified nucleic acids is essential in molecular diagnostics.

Purpose of the Study:

• To develop a fast and high-resolution capillary electrophoresis method for double-stranded DNA (dsDNA) fragment separation.
• To optimize buffer composition and capillary coatings for improved DNA fragment resolution.
• To apply the developed method for the quantitation of amplified mRNA transcripts.

Main Methods:

• Capillary electrophoresis (CE) using Tris-borate buffer with hydroxyethylcellulose.
• Analysis in fused silica capillaries (uncoated and phenylmethyl-coated).
• Addition of ethidium bromide for enhanced resolution and cation-based ionic strength adjustment.

Main Results:

• Achieved separation of dsDNA fragments (20-2200 bp) in under 20 minutes.
• Improved resolution with ethidium bromide, allowing separation of 1-2 bp differences.
• Demonstrated linear proportionality between resolution and cation size (Cs+ > Rb+ > K+ > Na+ > Li+).
• Successfully applied CE for quantitation of polymerase chain reaction-amplified androgen receptor mRNA transcripts with 3.4% coefficient of variation.

Conclusions:

• The developed capillary electrophoresis method offers rapid and high-resolution separation of dsDNA fragments.
• Optimized buffer and additives enhance DNA fragment resolution and enable accurate quantitation.
• This technique is suitable for analyzing amplified nucleic acids, such as mRNA transcripts, in molecular biology applications.