Interfacial pH Behavior at a Cell/Gate Insulator Nanogap Induced by Allergic Responses

Area of Science:

• Cellular Biology
• Immunology
• Biophysics

Background:

• Previous studies monitored allergic response-induced pH changes at mast cell/gate insulator nanogaps using ion-sensitive field-effect transistors (ISFETs).
• Interfacial pH behavior at these nanogaps requires further clarification using alternative methodologies.

Purpose of the Study:

• To clarify the interfacial pH behavior at mast cell/gate insulator nanogaps during allergic responses.
• To investigate the role of histamine in pH changes.
• To compare interfacial pH changes at nanogaps versus bulk solution.

Main Methods:

• Utilized laser scanning confocal fluorescence microscopy.
• Employed phospholipid fluorescein as an extracellular pH indicator fixed to mast cell membranes.
• Cultured mast cells on a substrate to form a nanogap.

Main Results:

• Interfacial pH at the mast cell/substrate nanogap increased upon activation of mast cells by allergen-IgE interaction.
• The observed pH increase is attributed to the release of basic histamine molecules.
• The magnitude of pH change at the nanogap interface was greater than in the bulk solution.

Conclusions:

• The study confirms increased interfacial pH due to histamine release during allergic responses.
• Accumulation of secreted molecules at the cell/substrate nanogap is suggested.
• Findings support the potential of potentiometric ion sensors (like ISFETs) for real-time detection of cellular function-induced pH changes.