Bright luminol electrochemiluminescence mediated by a simple TEMPO radical for visualized multiplex detection

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Biochemistry

Background:

• Electrochemical luminescence (ECL) is a sensitive detection technique.
• Luminol/H₂O₂ systems are widely used for ECL generation.
• Catalyst development is crucial for enhancing ECL efficiency.

Purpose of the Study:

• To investigate the use of functionalized TEMPO radicals as catalysts for luminol/H₂O₂ ECL.
• To explore the structure-activity relationship of TEMPO derivatives in ECL.
• To develop an enhanced ECL system for multiplexed biosensing.

Main Methods:

• Synthesis of various TEMPO radicals with different functional groups.
• Electrochemical characterization of TEMPO-catalyzed ECL reactions.
• Optimization of ECL generation using 4-hydroxyl-TEMPO and an enzymatic system.
• Demonstration of multiplexed detection using a single-electrochemical system (SEES).

Main Results:

• TEMPO radicals effectively catalyze the electrochemical oxidation of H₂O₂ and luminol.
• The para-position functional group on TEMPO influences catalytic activity and ECL generation.
• 4-hydroxyl-TEMPO, in combination with an enzymatic system, achieved a 9.6-fold enhancement in luminol ECL.
• The enhanced ECL enabled brighter imaging for multiplexed detection of cholesterol, H₂O₂, and glucose.

Conclusions:

• Functionalized TEMPO radicals serve as efficient catalysts for luminol/H₂O₂ ECL.
• The structure of TEMPO derivatives dictates their catalytic performance.
• This work presents a highly sensitive ECL system for advanced multiplexed biosensing applications.