Electrochemiluminescence immunosensor for thiamethoxam detection using NiFe-LDH-loaded Cu single-atom catalysts

Area of Science:

• * Electrochemistry and Sensor Technology
• * Nanomaterials and Catalysis
• * Environmental Analysis

Background:

• * Development of sensitive and specific detection methods for pesticides is crucial for environmental and food safety.
• * Existing electrochemiluminescence (ECL) sensors often face limitations in sensitivity and signal amplification.
• * Multimetallic catalysts offer unique properties for enhancing catalytic activity and signal output in biosensors.

Purpose of the Study:

• * To develop a highly sensitive and specific electrochemiluminescence (ECL) immunosensor for thiamethoxam detection.
• * To investigate the signal amplification effect of a novel multimetallic catalyst based on nickel-iron layered double hydroxides/copper single atoms (NiFe-LDHs/Cu-SAs).
• * To demonstrate the practical applicability of the developed sensor for real-world sample analysis.

Main Methods:

• * Synthesis of NiFe-LDHs/Cu-SAs as robust catalytic amplification elements.
• * Modification of gold electrodes with NiFe-LDHs/Cu-SAs.
• * Construction of the ECL immunosensor using C-dots labeled with thiacloprid DNA aptamers for molecular recognition.
• * Electrochemical and ECL measurements for signal detection and analysis.

Main Results:

• * The NiFe-LDHs/Cu-SAs significantly amplified the ECL signal of C-dots, enhancing sensor sensitivity.
• * The aptamer provided specific recognition of thiamethoxam, leading to effective ECL signal quenching upon binding.
• * The sensor exhibited a wide linear range (2-6000 × 10⁻¹² mol/L) and a low detection limit (6.52 × 10⁻¹³ mol/L).
• * High recoveries (90%-110%) were achieved in real sample analysis, indicating practical applicability.

Conclusions:

• * The developed ECL immunosensor, utilizing NiFe-LDHs/Cu-SAs for signal amplification and DNA aptamers for specificity, offers a highly sensitive and reliable method for thiamethoxam detection.
• * The innovative multimetallic catalytic strategy provides a promising platform for advancing sensor design in various analytical fields.
• * This approach demonstrates significant potential for environmental monitoring and food safety applications.