Preservation and Storage
Preservation and storage after sectioning can be an issue unless special measures are taken. The production of large batches of microarray sections is most efficient, but it raises a separate problem of antigenic loss due, presumably, to tissue oxidation. While this may not be the case if you use ZN-Formalin, regular buffered formalin is more commonly used and does not prevent oxidation after sectioning.
We, and others, have found loss of antigenicity if sections are stored for as little as a week prior to immunostaining. Work is underway to quantify this loss. It appears that loss is an oxidative process since the loss appears to be insensitive to storage temperature or retrieval conditions. For tissue microarrays, we have found that this loss can be prevented by sectioning without water (using the tape transfer system), removal of the degreasing agent after tape release by a short incubation in xylene, and finally re-coating the slides in paraffin prior to storage and storage in a nitrogen safe.