Profiling Luminal pH in Three-Dimensional Gastrointestinal Organoids Using Microelectrodes.

Area of Science:

• Gastroenterology
• Biotechnology
• Analytical Chemistry

Background:

• Gastrointestinal organoid models are crucial for studying digestive diseases.
• Analyzing the luminal environment of organoids is vital for their characterization and optimization.
• Current methods for luminal analysis in organoids are limited.

Purpose of the Study:

• To present a reproducible method for precise pH measurement within 3D human gastric organoids.
• To enable detailed functional characterization of the organoid luminal space.
• To validate the use of micromanipulator-controlled microelectrodes for organoid pH profiling.

Main Methods:

• Utilized commercially available, beveled glass pH microelectrodes (25 µm tip diameter).
• Advanced microelectrodes into the lumen (>200 µm) of 3D human gastric organoids suspended in Matrigel.
• Employed a reference electrode submerged in the surrounding culture medium for stable measurements.

Main Results:

• Demonstrated consistent luminal pH (~7.7 ± 0.037) within culture wells for gastric organoids.
• Achieved continuous pH measurements for a minimum of 15 minutes.
• Observed pH gradients in larger organoids, indicating high spatial resolution capabilities.

Conclusions:

• The described microelectrode method is a valuable tool for precise luminal pH measurement in 3D organoids.
• This technique enhances the functional characterization of complex organoid luminal environments.
• The versatility of microelectrodes is further confirmed for organoid analysis.