Real-time local oxygen measurements for high resolution cellular imaging

Area of Science:

• Biomedical Engineering
• Cell Biology
• Sensor Technology

Background:

• Current single-cell metabolic investigations are limited by the lack of high-resolution tools for measuring local oxygen partial pressure (pO2).
• Existing methods struggle to provide the spatial-temporal resolution needed for detailed pericellular and subcellular analyses.
• There is a need for adaptable sensors that can integrate with various single-cell experimental techniques without interference.

Purpose of the Study:

• To develop a novel optical sensor system, the OxySplot optrode, for high-resolution, real-time measurement of pericellular pO2.
• To enable simultaneous imaging of pO2 dynamics alongside other cellular functions like electrophysiology or chemo-mechanics.
• To provide a flexible and affordable tool for advancing single-cell metabolic and physiological research.

Main Methods:

• Development of OxySplot optrodes using silica micro-particles coated with oxygen-sensitive and insensitive fluorophores.
• Protection of optrodes with a polydimethylsiloxane (PDMS) polymer layer, forming OxyMats for cell adherence.
• Integration of OxySplots with confocal imaging systems for simultaneous pO2 and cellular event monitoring (e.g., mitochondrial membrane potential, intracellular calcium).

Main Results:

• The OxySplot optrodes provide accurate pericellular pO2 measurements with subcellular resolution.
• The sensor system demonstrates a rapid response time (~0.7s), significantly faster than traditional microelectrodes.
• Successful simultaneous measurements of pO2 with mitochondrial membrane potential and cytosolic calcium levels in cardiomyocytes were achieved.

Conclusions:

• The OxySplot/OxyMat system offers a highly adaptable and affordable solution for monitoring pO2 in single-cell studies.
• This technology overcomes limitations of existing methods, enabling simultaneous high-resolution imaging of oxygen gradients and cellular physiology.
• The developed optrodes are compatible with various imaging systems and experimental setups, facilitating broader application in cell biology research.