I want to leave the samples for electron microscopy in gluteraldehyde fixative over the weekend and continue the process next week. Will it affect the samples? How long can the samples be left in the fixative?
Not for a long time as the gluteraldehyde can destroy the details of the tissues.
Karnovsky fixative as a fixative for electron microscopy is better for the details
paraformaldehyde 2.0 gm
1M sodium hydroxide 2 - 4 drops
50% glutaraldehyde 5.0 ml (25% glut - 10 ml)
0.2M cacodylate buffer, pH7.4
Shaima,
What I have done with good success is to fix my samples (cells in suspension) with gluteraldehyde/formaldehyde fixative for the desired time, and then remove the fixative (as much as possible) and replace with PBS. You can keep your samples this way in the refrigerator over the weekend no problem. The residual fixative should keep everything preserved without over fixing. Hope this helps!
Hi Shaima,
I once sectioned rat liver for immunogold labelling that had been fixed 1983 and was sitting in the fridge all that time. I got beautiful morphology as well as a good signal for my labelling. Of course that depends on the antigen but it shows you that it is not necessarily counterproductive to keep samples in the fixative (definitely better than keeping them just in buffer).
I also regularly keep samples in the fridge in fixative and process them for regular TEM whenever I have time to do so.
Best wishes,
Christian
Not for a long time as the gluteraldehyde can destroy the details of the tissues.
Karnovsky fixative as a fixative for electron microscopy is better for the details
paraformaldehyde 2.0 gm
1M sodium hydroxide 2 - 4 drops
50% glutaraldehyde 5.0 ml (25% glut - 10 ml)
0.2M cacodylate buffer, pH7.4
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