Physical limits to magnetogenetics
- California Institute of Technology, United States
Figures
Figure 1
A TRPV4 channel (pink) inserted in the membrane with a ferritin complex (green) attached on the cytoplasmic side, approximately to scale.
The magnetic field B induces a moment m in the ferritin core, leading to a force F or a torque N on the ferritin particle, and resulting forces tugging on the channel. See text for details.
Figure 2
The steady-state temperature profile around a heated sphere in an infinite bath varies inversely with the distance from the center of the sphere.
The same argument applies to a ferritin sphere heated from its magnetic core (top) and a spherical cell with a large number of heated ferritins on its surface (bottom).
Tables
Table 1
Published measurements of specific loss power (SLP) for various magnetic particles of diameter d, taken at a magnetic field strength H and frequency f. The values in the column “SLP corr” are corrected for the field and frequency used by Stanley et al. (2015).
| Reference | Material | d [nm] | H [kA/m] | f [kHz] | SLP [W/g] | SLP corr [W/g] | Notes |
|---|---|---|---|---|---|---|---|
| Fortin et al. (2007) | Fe2O3 | 5.3 | 24.8 | 700 | 4 | 2.8 | |
| Fortin et al. (2007) | Fe2O3 | 6.7 | 24.8 | 700 | 14 | 10 | |
| Fortin et al. (2007) | Fe2O3 | 8 | 24.8 | 700 | 37 | 26 | |
| Fantechi et al. (2015) | Fe3O4 | 8 | 12 | 183 | 6.5 | 75 | |
| Hergt et al. (2004) | Fe2O3 | 7 | 15 | 410 | 15 | 49 | |
| Fantechi et al. (2014) | ferritin with Fe3O4 | 6 | 12.4 | 183 | <0.01 | <0.1 | per mass of only the metal ions |
| Fantechi et al. (2014) | ferritin with Co0.15Fe2.85O4 | 6.8 | 12.4 | 183 | 2.81 | 30 | per mass of only the metal ions |
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Physical limits to magnetogenetics
eLife 5:e17210.
https://doi.org/10.7554/eLife.17210
