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ref: -0 tags: DNA paint FRET tag superresolution imaging oligos date: 02-20-2020 16:28 gmt revision:1 [0] [head]

Accelerated FRET-PAINT Microscopy

  • Well isn't that smart -- they use a FRET donor, which is free to associate and dissociate form a host DNA strand, and a more-permanently attached DNA acceptor, which blinks due to FRET, for superresolution imaging.
  • As FRET acceptors aren't subject to bleaching (or, perhaps, much less subject to bleaching), this eliminates that problem...
  • However, the light levels used ~1kW / cm^2, does damage the short DNA oligos, which interferes with reversible association.
  • Interestingly, CF488 donor showed very little photobleaching; DNA damage was instead the limiting problem.
    • Are dyes that bleach more slowly better at exporting their singlet oxygen (?) or aberrant excited states (?) to neighboring molecules?

{1427}
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ref: -0 tags: superresolution imaging scanning lens nanoscale date: 02-04-2019 20:34 gmt revision:1 [0] [head]

PMID-27934860 Scanning superlens microscopy for non-invasive large field-of-view visible light nanoscale imaging

  • Recently, the diffraction barrier has been surpassed by simply introducing dielectrics with a micro-scale spherical configuration when using conventional optical microscopes by transforming evanescent waves into propagating waves. 18,19,20,21,22,23,24,25,26,27,28,29,30
  • The resolution of this superlens-based microscopy has been decreased to ∼50 nm (ref. 26) from an initial resolution of ∼200 nm (ref. 21).
  • This method can be further enhanced to ∼25 nm when coupled with a scanning laser confocal microscope 31.
  • It has achieved fast development in biological applications, as the sub-diffraction-limited resolution of high-index liquid-immersed microspheres has now been demonstrated23,32, enabling its application in the aqueous environment required to maintain biological activity.
  • Microlens is a 57 um diameter BaTiO3 microsphere, resolution of lambda / 6.3 under partial and inclined illumination
  • Microshpere is in contact with the surface during imaging, by gluing it to the cantilever tip of an AFM.
  • Get an image with the microsphere-lens, which improves imaging performance by ~ 200x. (with a loss in quality, naturally).