Selection of a Structure-Switching Aptamer for the Specific Methotrexate Detection

Area of Science:

• Biotechnology
• Analytical Chemistry
• Molecular Diagnostics

Background:

• Methotrexate (MTX) is a vital anti-cancer drug, but high doses necessitate careful blood concentration monitoring due to potential severe side effects.
• Current methods for MTX quantification are often complex, time-consuming, and costly, limiting routine clinical application.
• Developing a rapid, selective, and cost-effective assay for MTX monitoring is crucial for optimizing patient treatment and safety.

Purpose of the Study:

• To develop a novel, highly selective DNA aptamer for recognizing Methotrexate (MTX).
• To create a structure-switching fluorescent sensor for rapid and specific MTX detection.
• To evaluate the analytical performance of the developed sensor for MTX monitoring in biological samples.

Main Methods:

• Selection of a specific DNA aptamer for MTX using the capture-systematic evolution of ligands by exponential enrichment (C-SELEX) technique.
• Design and implementation of a structure-switching fluorescent sensor utilizing the selected MTX aptamer.
• Validation of the sensor's performance, including linear detection range and limit of detection (LOD), in buffer and serum samples.

Main Results:

• A highly selective DNA aptamer capable of recognizing MTX was successfully developed.
• The structure-switching fluorescent sensor demonstrated specific and rapid MTX detection.
• The sensor exhibited excellent analytical performance with a low LOD of 0.03 μM in buffer and 0.18 μM in 50% serum, with linear ranges of 0.1-2 μM and 0.5-10 μM, respectively.

Conclusions:

• The developed DNA aptamer-based fluorescent sensor provides a sensitive, selective, and rapid method for MTX detection.
• This novel assay presents a promising alternative to conventional methods for clinical monitoring of MTX blood concentrations.
• The aptamer and sensor design hold potential for inspiring future developments in therapeutic drug monitoring sensors.