A Rationally Designed Thymidine-Based Self-Assembled Monolayer on a Gold Electrode for Electroanalytical Applications

Area of Science:

• Electrochemistry
• Biosensing
• Materials Science

Background:

• Urate detection is crucial for diagnosing conditions like gout and kidney disease.
• Existing methods for urate quantification can be complex or lack specificity.
• Self-assembled monolayers (SAMs) offer a platform for developing novel electrochemical sensors.

Purpose of the Study:

• To prepare and characterize a self-assembled monolayer (SAM) of 1-(3,5-epidithio-2,3,5-trideoxy-β-D-threo-pentofuranosyl)thymine (EFT) on a gold electrode.
• To evaluate the performance of the EFT-based SAM electrode for the voltammetric sensing of urate.
• To assess the selectivity and practical applicability of the sensor in biological samples.

Main Methods:

• Preparation and characterization of EFT SAM on gold electrodes using Raman spectroscopy and electrochemical techniques (voltammetry, electrochemical impedance spectroscopy).
• Electrochemical sensing of urate in neutral solutions, assessing interference from ascorbate.
• Quantification of urate in human serum samples and comparison with clinical methods.
• Density Functional Theory (DFT) calculations to investigate interactions between EFT, ascorbate, and urate.

Main Results:

• The EFT SAM on the gold electrode effectively impeded electron transfer.
• The EFT-based electrode demonstrated successful voltammetric sensing of urate in neutral solution.
• The sensor exhibited excellent selectivity, with no interference from ascorbate, enabling urate quantification at micromolar levels.
• Urate levels in human serum samples were accurately determined, showing good agreement with clinical methods.
• DFT calculations revealed noncovalent interactions, including hydrogen bonding, between EFT and both ascorbate and urate.

Conclusions:

• The EFT SAM on gold electrodes provides a robust platform for selective and sensitive urate detection.
• The developed sensor is suitable for practical applications, including the quantification of urate in human serum.
• The findings highlight the potential of engineered SAMs for advanced electrochemical biosensing applications.