To extract RNA properly out of a whole Skin sample (mouse), how can I homogenize the sample? would the ceramic beads be enough for that? and later, which is better, TriFast or Trizol?
colleaques in Münster (Germany) tested the Bead Ruptor 24 homogenizer of Omni International for disrupting mouse skin for RNA isolation. They used 2.8mm ceramic beads in reinforced 2ml screw cap tubes. You might find some movies on youtube with pig skin. If you need more information feel free to contact me.
Why not pass them through 18 and 21-gauge needles?
I have used this method with success for RNA isolation in mice ventricles which have become rubberised (difficult to break down) as a result of RNALater. I have syringed a sample ten times up and down in QiAzol solution to break it down. I think with skin tissue this will be even easier.
Skin from fish is often hard material for isolating. We add liquid nitrogen and homogenate the skin in eppendorf tube. Then add proteinase K in buffer and incubate in 56 Celcius degrees 30 min.