It's Christmas!

Today, I learned how to operate an ultramicrotome.  This may seem like a fancy device, but it is actually quite simple.  "ultramicro-" implies that the instrument deals with the very small, while "-tome", comes from the Greek "temnein" to cut.  Thus, it can be inferred that an ultramicrotome cuts stuff into extremely thin slices - and that is exactly what it does!  The "stuff" it slices is sample - some bacteria perhaps - so that it can be viewed under a transmission electron microscope.  In transmission electron microscopy, a beam of electrons is shot at the sample, and the microscope detects the electrons that passed through, thus creating a detailed image of the sample.  

C. elegans embryo - example of a TEM image

    
The samples must be fixed, dried, and set in a resin.  My teacher for today, Paul, a microscopist and senior faculty member at Oak Crest, had prepared some samples years ago and used them for today's instruction.  It was a rectangular block of resin with some sample at the end of it.  He fixed it onto the segment arc of the ultramicrotome and first trimmed some resin off with a metal blade, looking through the lenses on this apparatus (it is much like a microscope, but with the added slicing capability), until the section of resin with sample in it was jutting out from the rest of the pod.  He moved on to the glass blade, fixing the segment arc onto a special port and the glass blade onto its throne beneath the ultramicrotome lens, and manually cutting the resin until the top of the bit of resin with sample in it was flat and some sample was exposed.  Behold a graphic to make more sense of this.  Hopefully it helps.

I was allowed to cut some resin myself.  The slivers that curled off looked like tinsel, with worms of pink and cotton candy blue wiggling around their edges, like the surface of a soup bubble.  It was marvelous.  The top of the jutting sample/resin block was "polished" by the glass blade, creating a very flat surface.  Next, Paul took out a small, clear, plastic box.  inside of it was a foam holder and inside of that was a blue block.  At the edge of that  block was, what other than, a diamond blade.  :'D It was beautiful.  He replaced the glass blade with this glorious instrument.

After operating it manually for a bit, he filled the trough behind the blade with water so that the slices made by the blade could float off, waiting to be collected later for TEM, and automated the slicing process.

The blue thing is the trough filled with water, and the gray rectangle is the diamond blade.  Floating on the surface of the water are the slices of sample from the resin block.  There are only a few nanometers thick.  That golden thing is the resin block, held in the segment arc.  The diamond blade is caught in mid-slice.  You can barely make out the sample - the dark spot on the edge of the resin block.    

It was at this time that I watched the diamond blade working its magic through the lens.  Here is a short video of this excellence.  Excuse the bad quality.  

It was like Christmas!  Each delicate sliver was a present, a snowflake, a bit of tinsel.  There you go - the connection between the title of this post and the post itself.  Got that over with.

Anyway,  once the slicing was done, the water was thrown out - slivers included - sadly.  They were only for demonstration, after all.  It was a pretty cool experience.  I remember Mrs. Matthews explaining electron microscopy to use, holding up a diamond blade that I could barely see.  Little did I know that I'd be getting a good look at such a blade one fine day...