Currently in botany class we’re using these silly safety razors, in conjunction with our fat fingers, to make thin slices of plant parts.
Is there a better tool? Maybe a pair of scissors with a specially-spaced gap? I read about something called a “microtome” that seems designed for the job, but it requires embedding the plant in some sort of hard resin prior to slicing (not practical for a beginning botany class).
What do the professionals do?
The professionals probably use a microtome, but you already said that wouldn’t be practical for you.
freeze it and use a safety razor. if you have the frozen sample come out just slightly out of a tube then it ads in holding and getting a thin uniform section.
professionals do use a microtome with frozen or embedded samples.
According to Larry Legg’s Microscopy Projects a bench microtome would indeed seem to be the way to go - sorry.
I don’t know why you discount mounting in blocks and using a microtome. There are waxes you can use as mounting/cutting media; just melt it on a hot plate and pour it around your sample. You can also make a crude hand-microtome out of a large nut and bolt. Cut along the nut by hand with a safety razor, unscrew the nut quarter turn or so, cut again to get a fairly even slice. Google reveals a handful of designs based on that idea, this one looks simple enough.
Now, this will take a little more time than cutting by hand, but the results will be much better, so the students won’t have to waste as much time staring at mangled bits of whatever under the microscope.
Agreed. You don’t need to embed in resin. Embed in paraffin wax instead. Easy and cheap. I’d place the sample in something like a bottle cap for imbedding rather than simply pouring the wax on it.
Its easy to build a hand microtome using a spool as shown in lazy’s link above. You can also buy one for about $50. Or even less. This one comes with embedding wax as well.
Just to be clear, I am the student and I can only use what I can bring with me, myself, to class. There is no departmental support, no hotplates available for us to use, we don’t see the samples until the class itself, and we can only use them during the 3-hour lab session (meaning no freezing or other overnight prep). We usually go through 10 or so different sections in those few hours so anything that takes more than a few minutes per section probably wouldn’t work.
That said, I’m intrigued by the hand microtome idea. Is there any way to use one without embedding, or if it absolutely requires embedding, to do so without long preparations?
I’m totally open to the idea of buying – or making! – my own hand microtome, but I’m not really sure I understand how the wax would work without melting first. Is it just a given that you’d have to wrap SOME sort of wax or resin around the sample first?
I wonder if there’s some sort of way to adapt, say, an old camera lens aperture to use as an adjustable-diameter holder. I dunno what you’d call that mechanism by itself.
You could probably jury rig some other sort of way to support your sample, but wax is damn easy (if messy). The basic requirement for cutting something so thin is even support for your sample. Otherwise, you’re crushing it between the blade and the table or whatever you hold it with.
Any heat source can melt the wax – bunson burner, hot plate, microwave – and if you cant find paraffin, any old beeswax or candle wax would probably suffice. I bet there’s something you can use.
Hmm. Do you melt the wax in a tiny beaker and then pour it over the sample and then wet-mount it?
How about a hot melt glue gun? There are special wax sticks for those. Or you could just use the glue.
This. You can embed the specimen in paraffin. Providing that you think the specimen won’t be damaged too much by being immersed in melted wax.
You can make a primitive home-made microtome out of a large nut and bolt. Screw the nut onto the end of the bolt just a few threads, leaving a “cup” inside the rest of the nut. Put the specimen in there and fill with wax. Turn the bolt in the nut to push the wax plug (with specimen) up a little bit, then slice off with single-edged razor. Turn bolt just a bit more to push the wax plug up just a bit more, and slice that off. There’s your thin specimen to stick under the microscope.
Here’s one site I just found with some instructions and pictures:
http://micro.sci-toys.com/microtome
You can google homemade microtome more others.