One of the most important and crucial things for my work is the Tissue. I isolate mesothelial cells and fibroblasts, which together take quite some time. Briefly, for mesothelial cells we use tripsin, for fibroblasts a mixture of collagenase-hyaluronidase. All together it can take up to 5-6 hours (which is pretty much especially if you start it at 2 pm).
Because tissue supply mainly depends on the surgeons and the surgeons' work depend on many other factors, you can never know when the tissue comes. If you are lucky it comes early (before noon), if not you can have a nice afternoon in the lab. As a Murphy's rule tissue usually comes when I have the least time for it (it means usually on Friday afternoon). So if there was even no tissue at all during the whole week, on Friday after lunch for sure I get the
message from the hospital that the tissue is waiting for me.
To overcome this 'problem', some people use different techniques for the isolation of these cells, they leave the tissue for overnight in the fridge (after tripsin) and thus divide the process into two parts (and liberate themselves from being in the lab in the afternoon). Interestingly, sometimes they can have as good results as those who do the process in one go.
So tissue supply in many aspects is very unpredictable, but the good news is that you can count with at least one tissue per week: Friday afternoon.