IF Solutions

Blocking buffer for immunofluorescence of cultured or primary cells
(also used for primary and secondary antibody incubation steps)

1x PBS (1 mM Ca2+, 1 mM Mg2+), pH 7.4
+ 0.2% saponin
+5% normal donkey serum (or goat, depending on secondary antibody species)
+1% BSA

Dissolve by stirring or gentle vortexing.  Filter sterilize and store aliquots at -20°C.

For permeabilization step, supplement the above with 0.1-0.3% Triton X-100.

4% formaldehyde solution for fixing cells
  1. Dissolve 4g paraformaldehyde in 80ml H2O in a fume hood
  2. Heat to 60 °C (approximately) on a hot plate with stirring until mostly dissolved; add a few drops of NaOH to help dissolve
  3. Cool to room temperature
  4. Add 10 ml 10x PBS (no Ca2+, Mg2+
  5. Filter with a 0.22 ┬ÁM disposable syringe filter
Use within 1 week or store aliquots at -20°C for up to 3 months.