Question: @ ash have you discovered new ways of creating microscopes and if so how many?

Ashley Cadby answered on 30 Jun 2012:

We have three new ways of performing microscopy. I should say that in all of science it is unlikely that one person developers a completely new way of doing things we all work together informing each other through writing papers. So the three ways we image systems are based on our ideas and other peoples ideas.

So before we start Paige probably has one of the best microscopes you can buy, her microscope has a resolution of 250nm, that means she can only see things as being separated if they are more than 250nm apart. So she would not be able to see any detail inside structures which are smaller than 250nm

The first method we have is called, scanning near field microscopy (SNOM). Here we take a very sharp glass needle and coat it in aluminium. The glass needle is about 1 micron at the end, we drill a very small hole about 50nm through the bottom of the aluminium, this allows a very small amount of light to escape from the bottom of the glass tip. If we bring the tip really close to the sample we are interested in we know the light will only excite 50nm of the surface. What we also do is use a really fast laser to excite the sample, through the tip. As we drag the tip across a sample stopping at each 50nm and collecting the light that paases through the sample we can build up an image This microscope has a resolution of 50nm, ie we can see structures down to 50nm. We use this microscope along with the fast laser to look at what happens in solar cells when light excites them. 50nm sounds really good, but in solar cells we really want to see down to 10nm, however we have learnt a lot even with 50nm resolution.
To get better than 50 nm we have worked on a microspe that again uses a short tip, but this time we touch each molecule in turn and look for changes in the light we see. So if we have a collection of green and red molecules and when we touch the sample we see the green signal change we know the molecule we have touched was green. We should be able to do this for every molecule and should be able to make images where we can see the colour of every single molecule. This technique has a resolution of 10nm and we currently are ap
Lying for a patent. However, it really hard to use.

Finally. The last one is called STORM. This is the one we use to look at bacteria. When I said that resolution means how close two,object can be before they look like one, what I didn’t tell you was that if you have one molecule you can see exactly where it is. It a little like a single tree on a hill, it’s really easy to see where the tree is but for a forest on a hill it’s really difficult to see how many trees there are and where they are.

Ok so if you look at my profile one of the pictures is an animation of a load of flashes. Each one of those flashes is a single molecule being turned on for a few millisecond. Because we only turn a few on in each frame, and because there are no other turnd on molecules near by, we can work out exactly where each molecule is. We do this for every molecules in the bacteria and build up an image (over 10 minutes). This image has a resolution of 20 nm and can be used to study biology.

Ash