Table 1.
Comparison of NoRI and existing methods for single cell biomass measurement
| Method | Measured parameter | Measurement characteristics | Sample types | References | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mass | Mass density | Absolute quantification* | Subcellular resolution | Chemical composition | Suspended cells | Adherent cell culture | Cells in tissue | Live sample | |||
| NoRI (Normalized Raman Imaging) | Biomass composition and concentration | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | This work |
| SRS (Stimulated Raman Scattering) | Biomass composition and concentration | ✓ | ✓ | ✕ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 25, 29 |
| SMR (Suspended Microchannel Resonator) | Buoyant mass, volume, density | ✓ | ✓ | ✓ | ✕ | ✕ | ✓ | ✕ | ✕ | ✓ | 12–14, 21 |
| QPI (Quantitative Phase Imaging) | Refractive index (dry mass density) | ✓ | ✓ | ✓ | ✓ | ✕ | ✓ | ✓ | ✕ | ✓ | 15–17, 23, 24 |
| Particle tracking, FCS, FRAP | Diffusion | ✕ | ✓ | ✕ | ✓ | ✕ | ✓ | ✓ | ✓ | ✓ | 9, 71 |
| Inertial picobalance | Buoyant mass | ✓ | ✕ | ✓ | ✕ | ✕ | ✕ | ✓ | ✕ | ✓ | 18 |
| Electron microscopy | Number and volume of cellular structures | ✓ | ✓ | ✕ | ✓ | ✕ | ✓ | ✓ | ✓ | ✕ | 8, 9 |
| Light microscopy | Protein or lipid stain, volume of cell or nucleus | ✓ | ✓ | ✕ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 4, 10, 11, 72, 73 |
| Flow cytometry | Light scattering, protein stain, UV absorption | ✓ | ✕ | ✕ | ✕ | ✓ | ✓ | ✕ | ✕ | ✓ | 19, 20 |
*Absolute quantification of mass or mass density in physical units. Volume, area, or intensity in arbitrary units are considered semi-quantitative or relative measurements of biomass.