Microphysiometry

Microphysiometry is the in vitro measurement of the functions and activities of life or of living matter (as organs, tissues, or cells) and of the physical and chemical phenomena involved on a very small (micrometer) scale.^[1][2] The term microphysiometry emerged in the scientific literature at the end of the 1980s.^[3][4]

The primary parameters assessed in microphysiometry comprise pH and the concentration of dissolved oxygen, glucose, and lactic acid, with an emphasis on the first two. Measuring these parameters experimentally in combination with a fluidic system for cell culture maintenance and a defined application of drugs or toxins provides the quantitative output parameters extracellular acidification rates (EAR), oxygen consumption rates (OUR), and rates of glucose consumption or lactate release to characterize the metabolic situation.

Due to the label-free nature of sensor-based measurements, dynamic monitoring of cells or tissues for several days or even longer is feasible.^[5] On an extended timescale, a dynamic analysis of a cell's metabolic response to an experimental treatment can distinguish acute effects (e.g., one hour after a treatment), early effects (e.g., at 24 hours), and delayed, chronic responses (e.g., at 96 hours). As stated by Alajoki et al., "The concept is that it is possible to detect receptor activation and other physiological changes in living cells by monitoring the activity of energy metabolism".^[6]

See also

• Organ-on-a-chip

References

1. McConnel HM, Owicki JC, Parce JW, Miller DL, Baxter GT, Wada HG, Pitchford S (1992). "The Cytosensor Microphysiometer: Biological Applications of Silicon Technology", Science, 257, 1906-1912
2. Brischwein, M.; Wiest, J. (2018). "Microphysiometry". Bioanalytical Reviews. Springer. doi:10.1007/11663_2018_2.
3. Hafeman DG, Parce JW, McConnell H (1988). "Light-addressable potentiometric sensor for biochemical systems", Science 240, 1182–1185
4. Owicki JC, Parce JW (1990). "Bioassays with a microphysiometer". Nature 344, 271–272
5. Wiest, J. (2022). "Systems engineering of microphysiometry". Organs-on-a-Chip. Elsevier B.V. doi:10.1016/j.ooc.2022.100016.
6. Alajoki ML, Bayter GT, Bemiss WR, Blau D, Bousse LJ, Chan SDH, Dawes TD, Hahnenberger KM, Hamilton JM, Lam P, McReynolds RJ, Modlin DN, Owicki C, Parce JW, Redington D, Stevenson K, Wada HG, Williams J (1997). "High-performance microphysiometry in drug discovery", Devlin JP (ed) High Throughput Screening: The Discovery of Bioactive Substances. Marcel Dekker, New York, 427–442.