TABLE II.
Selected advantages and limitations of each class of methods.
| Method class | Advantages | Limitations |
|---|---|---|
| Cantilever | High dynamic range for stress and strain | Single-cell throughput |
| Insensitive to single pN-scale forces | ||
| Simultaneous stress and strain measurements | ||
| Measurement can be conflated when probing nuclei on soft substrates | ||
| Variable strain rates | ||
| Sensitive to chromatin- and lamin-based mechanics | ||
| Capable of ligand specific transduction pathway | ||
| Tweezers | Capable of single pN force measurements | Low dynamic range for stress and strain |
| Simultaneous stress and strain measurements | Single-cell throughput (unless parallelized with permanent magnet) | |
| Highly localized stress application | ||
| Variable stress profiles (twisting vs extension/compression) | ||
| Capable of ligand specific transduction pathway | ||
| Confinement | Single- or multi-cell stress application | Limited to physiological cases related to nuclear confinement |
| Sensitive to lamin-based nuclear mechanics (MA specifically) | ||
| Insensitive to chromatin-based mechanics (MA specifically) | ||
| Useful in studying downstream consequences of nuclear deformation | ||
| Confinement can alter the cytoskeletal organization and cause blebbing. | ||
| Incompatible with isolate | ||
| nuclei (confined migration specifically) | ||
| Environmental | Not physically invasive | Not capable of measuring mechanical forces or material properties alone |
| Useful in mimicking different physiological conditions | ||
| Can be coupled with other methods to measure mechanical forces | Necessitates visualization/microscopy when used alone | |
| High-throughput, multi-cell approach | ||
| Substrate Strain | High dynamic range of strain, frequency, and duration | Limited to lateral strain application |
| High-throughput, multi-cell approach | Generally unable to quantify the magnitude of force applied to each cell | |
| Limited in specificity of strain application | ||
| Useful in studying downstream consequences of mechanical forces | ||
| Suspension | High-throughput, single-cell measurements | Isolating the contribution of the nucleus is nontrivial |
| Variable mechanisms of applying stress | ||
| Limited specificity of strain application | ||
| Substrate does not conflate mechanical measurements | ||
| Cannot be used in conjunction with monolayers and/or tissue samples | ||
| Rapid timescale of nuclear deformation | ||
| Microscopy | Not physically invasive | Subject to all optical aberrations associated with fluorescence microscopy |
| Capable of measuring material properties of nuclei | ||
| Can be used to measure nuclear mechanics in vivo | Current debate over the role of water content in measuring elasticity | |
| Can be coupled with external devices to apply specific strains | ||
| Necessitates fluorescence microscopy, which can in turn damage the specimen | ||
| Can be used with various models and layers of complexity |