Electrochromatographic retention studies on a flavin-binding RNA aptamer sorbent

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Aptamers are specific oligonucleotide-based recognition elements.
• RNA aptamers targeting flavin mononucleotide (FMN) were immobilized onto fused-silica capillaries.
• Existing evaluation theories were insufficient for these aptamer-functionalized capillaries.

Purpose of the Study:

• To develop a novel method for evaluating aptamer-coated capillaries for open-tubular capillary electrochromatography (OTCEC).
• To quantify the binding characteristics (k' and k(CEC) values) of FMN and flavin adenine dinucleotide (FAD) in these capillaries.
• To investigate the influence of magnesium ion (Mg2+) concentration on binding.

Main Methods:

• Covalent immobilization of an FMN-specific RNA aptamer onto fused-silica capillary walls.
• Combination of open-tubular capillary electrochromatography (OTCEC) and flow-counterbalanced capillary electrophoresis for evaluation.
• Determination of retention factors (k') and electrochromatographic constants (k(CEC)) for FMN and FAD.

Main Results:

• A new evaluation method was established, overcoming limitations of existing theories.
• The method successfully extracted k' and evaluated k(CEC) values for the aptamer-coated capillaries.
• Measured k' values ranged from 0.0951 to 0.2530 for FMN and 0.0255 to 0.1118 for FAD.
• The dependence of these values on Mg2+ concentration was explored.

Conclusions:

• The developed method provides a robust way to evaluate aptamer-functionalized capillaries for OTCEC.
• This technique enables precise characterization of aptamer-analyte interactions, specifically for flavin compounds.
• The study highlights the importance of Mg2+ in modulating aptamer-analyte binding within the capillary system.