Selective detection of endogenous thiols using microchip-based flow analysis and mercury/gold amalgam microelectrodes

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Biomedical Engineering

Background:

• Erythrocytes contain glutathione (GSH), a key antioxidant vital for cellular redox balance.
• Accurate and rapid measurement of intracellular GSH is essential for understanding erythrocyte function and disease states.
• Existing methods for GSH detection can be time-consuming or lack the necessary sensitivity and selectivity.

Purpose of the Study:

• To develop and characterize a microchip-based flow injection analysis system for the selective detection of intracellular glutathione (GSH).
• To integrate thin-layer mercury/gold amalgam microelectrodes for sensitive electrochemical detection of GSH.
• To demonstrate the platform's capability for on-chip erythrocyte lysis and GSH quantification.

Main Methods:

• Fabrication of thin-layer gold microelectrodes and their amalgamation with mercury via electrodeposition.
• Integration of microelectrodes with a microchip for flow injection analysis (FIA).
• On-chip erythrocyte injection, lysis, and electrochemical detection of released GSH at low potentials.

Main Results:

• The fabricated mercury/gold amalgam microelectrodes exhibited linear responses for GSH and cysteine in FIA.
• The microchip device successfully detected changes in GSH concentration using on-chip injection.
• Quantification of GSH in rabbit erythrocytes yielded 312 amol/cell, consistent with literature values.

Conclusions:

• The developed microchip platform offers selective, sensitive, and rapid detection of intracellular GSH in erythrocytes.
• The system's short analysis time (approx. 5 s) and continuous sample introduction are advantageous for studying dynamic biological systems.
• This technology holds promise for investigating the glutathione redox system and related erythrocyte disorders.