Table 1.
Comparison of the typical settings for the two main types of O2 respirometry.
| Parameter | Mammalian Cell Respirometry (1) |
Bacterial Cell Respirometry (2) |
Comments |
|---|---|---|---|
| O2 Sensor/probe type | Various, soluble or solid-state |
Various, soluble or solid-state |
Interchangeable, different dyes |
| Assay substrate | Microwell plates, special substrates |
Standard plates and plastic tubes, sachets |
More critical for (1) than (2) |
| Sample sealing options | Oil seal, sealable microchambers |
Oil seal or no seal (liquid barrier) |
Critical for (1) Less critical for (2) |
| Assay volume and sample type | 0.05–1 mL, simple and uniform |
0.1–50 mL, complex and variable |
Larger for (2) |
| Cell number range | 104–2 × 105 per well | Single-cell—107 cells/mL | May vary for the different apps |
| Assay T, °C | 37 °C | 7 °C, 30 °C, 37 °C | Cell-specific |
| Instrumentation | Benchtop reader with T-control |
Handheld reader + Incubator |
Stationary vs transportable |
| Measurement time | 5 min–2 h | 1–16 h | Longer for (2) |
| Frequency of reads | 1–5 min Or end-point reads |
10–60 min Or end-point reads |
Slower for manual readers |
| Repeated measurements | Desirable and common | No | Samples discarded |
| Signal monitored | Int, LT, [O2] | Int, LT, [O2] | LT is preferred |
| Profile shape | Linear or extended sigmoid | Steep sigmoid | May be different in some apps |
| What parts are analyzed and how | Linear part–signal slope or [O2] slope |
Signal onset—time to threshold, TT |
|
| Calibration used | Sensor LT vs [O2] | TT vs log(CFU/mL) | Once-off calibrations |
| Assay readout | Absolute or relative OCR values |
Cell counts—CFU/g or CFU/mL |
May vary in different apps |