Specific Aspects of SELEX Protocol: Different Approaches for ssDNA Generation.

Area of Science:

• Biotechnology
• Molecular Biology
• Medicinal Chemistry

Background:

• Synthetic DNA aptamers offer potential in medicine as molecular sensors and for targeted drug delivery.
• Systematic Evolution of Ligands by Exponential Enrichment (SELEX) is a key technology for aptamer selection, established three decades ago.
• SELEX involves iterative cycles of target-based partitioning and PCR amplification, with diverse protocol variations complicating method selection.

Purpose of the Study:

• To comparatively analyze different methods for single-stranded DNA (ssDNA) generation during the SELEX process.
• To identify the most optimal and practical approach for ssDNA isolation in aptamer selection.

Main Methods:

• Four established ssDNA generation techniques were evaluated in parallel.
• Methods included: (a) lambda exonuclease digestion post-PCR, (b) denaturing polyacrylamide gel electrophoresis (PAGE) after extended-primer PCR, (c) asymmetric PCR, and (d) asymmetric PCR utilizing a primer-blocker.

Main Results:

• The four ssDNA generation methods were assessed based on specificity, efficiency, reproducibility, and duration.
• Comparative analysis revealed significant differences in performance across the evaluated techniques.

Conclusions:

• Asymmetric PCR employing a primer-blocker demonstrated superior performance in ssDNA generation for SELEX.
• This optimized method offers improved specificity, efficiency, and reproducibility for aptamer selection.