Have you ever read one of those stir-fry recipes that calls for freezing the meat for a few minutes to that you can easily slice it really thinly? As a cook, I see that advice, but then often ignore it because I’m too impatient. As a result, the meat tends to squish as I try to slice it (with my less than super-sharp knife), and I’m left with pieces which are uneven in thickness, and even at their best, are thicker than really should be used in a stir-fry. But how does one cut through engineered tissue? When one is talking about slicing one’s samples for analysis, those are the results you’ve worked long and hard to create, and no corners should be cut (pun intended).
You can’t just slice willy-nilly and eat the results. I don’t even want to think about eating tissue engineered meat – that’s a blog post for later this week.
One method is indeed to freeze it, that’s called “cryo-sectioning”, “cryo” actually being Greek for “icy cold”! Another technique is to embed the tissue in plastic and then cut it. Ever tried to cut plastic accurately? Only a small handful of technicians in the US are experts in that. But let us think about the reasons why the stir-fry recipe tells you to freeze the meat. As the meat freezes it becomes harder, and more stable; hence, easier to cut.
What we can do is embed the samples in wax. Wax infiltrates the entire tissue (if it’s soft) and stabilizes it, making it possible to cut thin slices without any squishing. And the slices that we can cut are super-thin! A microtome could slice a human hair. Length-wise. This means that we can very precisely see what is going on in the tissue that we have made.
To skip a lot of the science jargon, the process is basically thus:
1. The tissue is slowly transitioned to being in a wax solution.
2. The tissue can then be placed in a mold with more wax and let to cool.
3. The mold is then removed and the block can be cut
Ever seen a block of amber with a fly or something prehistoric in it in a natural history museum? That’s what this is like, except unfortunately the samples don’t look nearly as cool as flies. And they’re in wax, not amber; so aren’t worth much unless you’re the scientist that made them. My precious…….
So there you have it! The non-scientist’s version of how to slice bone.