Journal Club: Expansion Microscopy 06/19/15

Chen, Tillberg and Boyden, Expansion Microscopy

• presented by Yari
• approach
  • label sample
  • gelation in polyectrolye network
  • proteolysis tissue / polymer sample
  • expand in water
  • image
• super absorbant polymers (used in diapers)
  • sodium acrolyate + acrylomide
• special probes required. Can’t just use labeled antibodies (they’ll get eaten)
  • add a single-stranded oligo-nucleotide to antibody. Corresponding oligo with dye and polymer attaching group (methacryloyl) hybridized to this. Thus it sticks to the gel.
• primarily getting linear expansion factor of 4. Test up to factor of 9 (possibly at cost of stability).
• initial polymer is highly crumpled because its in 2M salt. Expansion is pure water.
• rescaled expanded sample, looks same before and after expansion. Nice.
• compare SIM images before and after. claim ~60 nm resolution
• see some non-uniform distoration. On order of distoration of PSF of confocal. Mostly a problem only at very large distances. (could correct for this with a few embedded fiducials)
• clathrin pits look good too.
• tissue is extremely clear. (detergent)