PMID-19199762[0] Optical Detection of Brain Cell Activity Using Plasmonic Gold Nanoparticles
- Used 140 nm diameter, 40 nm thick gold disc nanoparticles set in a 400nm array, illuminated by 850nm diode laser light.
- From my reading, it seems that the diameter of these nanoparticles is important, but the grid spacing is not.
- These nanoparticles strongly scatter light, and the degree of scattering is dependent on the local index of refraction + electric field.
- The change in scattering due to applied electric field is very small, though - ~ 3e-6 1/V in the air-capacitor setup, ~1e-3 in solution when stimluated by cultured hippocampal neurons.
- Noteably, nanoparticles are not diffraction limited - their measurement resolution is proportional to their size. Compare with voltage-sensitive dyes, which have a similar measurement signal-to-noise ratio, are diffraction limited, may be toxic, and may photobleach.
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[0] Zhang J, Atay T, Nurmikko AV, Optical detection of brain cell activity using plasmonic gold nanoparticles.Nano Lett 9:2, 519-24 (2009 Feb) |
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