Two recent postings have implied colloidal gold probes have a relatively short half life. Could people comment on how long their probes are stable and how they store them.
Shelf life depends on the protein conjugated to the gold and the batch.
A conjugates that were a year and a half old. Other times they have gone bad much more quickly. It is always best to have a positive control for activity of the gold if it has been several weeks since the last use. If the gold is in a glycerol solution it can be frozen to extend its useful life. Three months tops for me, stored in the original container at 4C, regardless of supplier.