MicrobeHunter.com Microscopy Forum

Hi together,
I'm preparing a video conference meeting on stomata and did a couple of nail polish impressions and hand sections today. Here is a photo of an impression in UV hardening nail polish of the underside of a tulip leaf. I put a tiny droplet of the nail polish on the leaf and then press a 18mm rectangular cover slip with pincers on it. Through the gap between the pincer's legs I shine with an UV flashlight for 30 seconds. The impression can be removed together with the cover slip. Then it is put onto a slide and sealed with narrow strips of adhesive tape.

Here an image with the old Zeiss DIC, just the green channel.

Bob

Very impressive, Bob !!

MichaelG.

[ do please forgive the pun ]

That's very cool Bob. Any reason why did you use UV curing nail polish? To make it dry faster, I assume. Am i right?

I agree very impressive Bob! //KD

Very nice and inspiring to try it, Bob.

Well, this is how I came to UV hardening nail polish: I used to teach commercial apprentices some technical stuff at work, each one a month. One morning I came into my office and my apprentice of the month held her hands in my direction and said "I did this myself!". My interest was awakened: "New DIY hands? "No", she said, "can't you see my new finger nails???" This was my introduction in UV hardening substances and I immediately bought an UV lamp, in pink: https://www.ebay.de/itm/36W-UV-Lampe-Li ... SwlxRaU4s8

The big advantage of using a UV glue is the quick curing. The leaf doesn't get much time to react and shrivel while the glue hardens. here I didn't use the pink lamp but an UV torch that allowed to apply the light in a very conentrated way.

I tried mounting with LOCA TP2500, an elastic UV hardening glue used for phone displays. By eye the imprint stays visible, und the microscope-invisible, even in DIC and phase.
Next was Pleurax: Contrast is better but overall not a great method.
Since the imprint is already attatched to the cover slip there is no glass-air-imprint combination, but just glass-imprint. I didn't try but high power work would work.

This chinese "Topcoat" nail polish is quite hard and brittle. It can be used to make small lenses for jndemanding purposes. It doesn't adhere well to a cover slip when applied in thick layers like a drop hanging from the slide.

I even made some comparisons of contrast techniques. Oblique and DIC were best, plain bright field and phase were not able to compete.

Bob

That is pretty nifty!

To show that no expensive DIC is necessary here a single shot with oblique lighting.

Nice job Bob. I have a few tubes of UV curable glue for repairing PCBs. I'll like to try your recipe and see how it works. The glue I have is not fully transparent, but I think it doesn't matter.

Hi Daroush,
I would just try what you have. A semi-transparent glue might be just perfect as you get an amplitude object from it. One useful property would be good adherance to hard surfaces, this should be given in a glue that is intended for mounting electronic components. The glue should have a suitable viscosity to fill the pores and there should be no particles in it like flakes, it should be stained right through.

What might also work is quick hardening 2k epoxy as it hardens by itself and leaves an imprint that is directly attatched to the cover slip. The classic method would be solvent based nail polish or UHU hart glue that dries on the leaf and is then peeled of and mounted. But this will probably not giv ethe same quality of slide.

To carry the UV nail polish attempt further would be to stain it a see how a light stain would influence the image quality.

The stomata are mostly on the lower sides of the leaves and they are arranged differently from plant to plant. It is possible open and close the stomata by means of light and shadow, sugar solution (e.g. 0,5 mol) or plain water. So with enough determination the functionality of the stomata can be shown nicely.

Bob

Very interesting series of posts. Thanks for starting it off, MicroBob, with your example of a variation on an old method that appears to give excellent results.
Tom W.

Great idea Bob! Very interesting approach for studying surfaces of objects otherwise not suitable for transmitted light microscopy.

Here a rough comparison of images taken with different contrast techniques and little image editing, all single shots. On cause there is a lot of room for improvement in every shot, it just shows round about how much potential is there.

Bob

Another simple way to observe stomata: Hand sections!
By omitting the microtome one gains flexibility and speed. Aim is not a planparallel section but a wedge that at least has the right thickness in an area.
For thin objects it is feasible to try to cut planparallel and advance in tiny increments. This can be done by using the finger that holds the specimen as a fulcrum and angle it back from cut to cut: https://vimeo.com/409525546

It is possible to do crosscuts as shown on the pine needle (Etzold FCA stain)
It is alos posible to do flat sections that remove a bit of epidermis, shown here on a Red Lucky Clover.

The first image is very eye catching to me. Nice tips/techniques too.

I agree, daruosha.
I really like the first image.

Hi, can you give me the procedure to Etzold FCA staining using Alcian blue as A. Can you also tell me how to prepare solutions of Alcian Blue, Fuchsine and Chrysoidine, and how I can stain hand microtome section?

I love the techniques here!