Oxygen consumption and oxygen diffusion properties of multicellular spheroids from two different cell lines

Area of Science:

• Biophysics
• Cell Biology
• Biomedical Engineering

Background:

• Multicellular spheroids are complex 3D models used in various research fields.
• Understanding oxygen diffusion and consumption within spheroids is crucial for interpreting experimental results.
• Previous methods lacked precision in quantifying oxygen transport properties.

Purpose of the Study:

• To develop and apply a novel method for assessing oxygen (O2) gradients in multicellular spheroids.
• To quantify O2 consumption rate (Q) and Krogh's diffusion constant (KS) in EMT6 and V79 spheroids.
• To investigate the influence of cell type and spheroid size on O2 transport parameters.

Main Methods:

• Utilized microelectrodes for precise pO2 measurements within spheroids.
• Applied a newly developed method to evaluate pO2 gradients.
• Calculated volume-related O2 consumption rate (Q) and Krogh's diffusion constant (KS).
• Derived estimates for water content (W), O2 diffusivity (D), and O2 solubility (alpha).

Main Results:

• Significant differences in O2 consumption and diffusion properties were observed between EMT6 and V79 spheroids.
• V79 spheroids exhibited higher O2 consumption (Q) but lower KS, W, D, and alpha compared to EMT6 spheroids.
• O2 consumption rate (Q) decreased with increasing spheroid diameter for both cell types.
• Q in spheroids was lower than in corresponding single cells.

Conclusions:

• Cell line choice profoundly impacts O2 consumption and diffusion characteristics in multicellular spheroids.
• The developed method accurately predicts measured pO2 distributions, validating its utility.
• Findings provide essential data for interpreting spheroid-based experiments and developing predictive models.