Modified electrodes based on lipidic cubic phases.

Area of Science:

• Materials Science
• Biochemistry
• Electrochemistry

Background:

• Lipidic cubic phases are well-ordered, 3D structures with aqueous channels.
• These phases, particularly monoacylglycerol-based ones, can incorporate and stabilize proteins.
• They form stable structures like Ia3d and Pn3m at specific hydration levels.

Purpose of the Study:

• To explore the potential of lipidic cubic phases as electrode-modifying materials.
• To investigate their use in hosting enzymes and synthetic catalysts for electrochemical applications.
• To determine the transport properties of molecules within these cubic phase films.

Main Methods:

• Formation of lipidic cubic phases (Pn3m) with monoolein at >20% hydration.
• Coating solid substrates, such as electrodes, with the viscous cubic phase material.
• Utilizing voltammetry with both normal-size and ultramicroelectrodes to study diffusion.
• Immobilizing enzymes (e.g., laccases) within the cubic phase matrix on electrodes.

Main Results:

• Lipidic cubic phases provide a stable environment for enzyme immobilization on electrodes.
• Catalytically active modified electrodes were demonstrated for determining cholesterol, CO2, and oxygen.
• Voltammetry effectively quantified the concentration and diffusion coefficient of electroactive probes within the cubic phase.
• Enzymes like laccases were successfully immobilized for dioxygen monitoring, maintaining electronic contact via electroactive probes.

Conclusions:

• Monoolein-based lipidic cubic phases are effective matrices for creating catalytically active biosensors.
• The high viscosity and ordered structure facilitate enzyme immobilization and analyte detection.
• Electrochemical techniques, particularly voltammetry, are suitable for characterizing transport phenomena in these modified electrodes.