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Comparative Physiology @ Guelph

Staining Grids for TEM

Stains, Reagents, Materials:
Saturated uranyl acetate in 75% methanol
Lead citrate – from a mixture of Na citrate and Pb nitrate
KOH pellets – for mopping up CO2
Whatman filter paper #1
Al foil for a clean work area
Glass Petri dishes
6 rinse bottles (scint vials)


  • Fill rinsing bottles with dH2O
  • Filter UA solution into clean scintillation vial
  • Put KOH pellets at edge of Petri
  • Place drops of UA on parafilm (one per grid)
  • Float grids, section side down on UA drops for 6 minutes
  •     Stagger the grids by 2 minutes
  •     Keep track of which is which!
  • Transfer to rinse #1 (don’t let them dry in between)
  •     Jiggle up and down in rinse water
  •     Then rinse with dH2O from squirt bottle (not directly)
  • Repeat with rinses 2,3
  • Transfer grid to filter paper using filter paper wedge
  • Let dry completely
  • Rinse and clean forceps before starting Pb citrate
  • Handle bottle of Pb citrate carefully to avoid precipitation
  • Repeat with Pb citrate, but only stain for 4 minutes