Jakob and the SEM

jess_graphicalabstract_armourersA few weeks ago I went to the networking evening of the grant winners of the Armourers and Brasiers Gauntlett Trust, where I met Jakob Koh, a 16-year-old boy who is studying Maths, Chemistry, Biology and Latin A-Levels. At the event I presented a poster which didn’t win any prizes (the poster prize went to a 17-year old called Alysha from Simon Langton Grammar). Not only did my dramatic loss (check out that poster, it’s a real peach) make me realise that young people are doing the best science, but meeting Jakob did. Jakob runs the Scanning Electron Microscope (SEM) at his school. If you know what a scanning electron microscope is, you’ll be pretty amazed by that too.

SEMImageScanning electron microscopes work by firing a beam of electrons from an ‘electron gun’, which works by heating up a filament and cause electrons to jump off at an energy of 5 – 30 keV. The electrons are accelerated down the microscope column using a negatively charged anode (the electrons are negative and are pushed by the negatively charged anode). Using a series of magnetic lenses the electrons are focussed onto our sample, then scattered in all directions. The amount they scatter by depends on the type of surface we’re looking at (rough/smooth, thick/thin). Sometimes the electrons are so energetic they emit X-Rays, which can be used to track the elemental composition of a sample. After the first year of my undergraduate degree I was lucky enough to spend the summer with a brilliant scientist, Dr Nicky Mordan at UCL. Dr Nicky Mordan runs the electron microscopy unit at the Eastman Dental Hospital, where she has a group of MSc and PhD students using her SEM and TEM to map dental decay. I didn’t mention the fact that this week I’d missed an appointment with my dental hygienist (or that I’ve just had to have a filling…). Nicky made me feel so wonderful when I was a confused 19-year-old wondering whether physics was for her- she showed me that there were kind and compassionate people in scientific research, talked to me like I was on her level and let me use her kit on my own. Armed with her confidence and support I became captivated by characterisation- which probably led me to my PhD. Whilst I was there I made a series of instructions to understand how to prepare samples (sputter coating) and run the SEM. Preparing the samples requires you to dry them out whilst retaining their structure. Nicky explains it really well- imagine trying to take all the water out (dehydrate) of a tomato whilst maintaining the tomato shape. To do that you take it through a series of graded alcohols (0, 10, 20 … 90 %) and then use a chemical drying agent HMDS, which changes the surface tension so that water can evaporate quickly without ruining the packing structure. Great scientists like Nicky don’t just publish lots of papers but they also manage to explain science in a way anyone can understand. We use HMDS when we prepare organic electronic devices to encourage the organic semiconductors to stick to the surfaces below.

So far Jakob’s spent his sixth form doing SEM of his baby teeth: he’s got a control sample, one which he bathes in coca cola and one which he keeps in orange juice. Jakob’s determined to study medicine, despite my best efforts to convince him otherwise, but I’m pretty sure he’ll end up an academic doctor. Times have changed in the NHS, and with the human tissue act it’s even hard for Nicky to get her hands on people’s teeth. Even though not many people want their teeth once they’ve been taken out, teeth contain tiny bits of human pulp which belong to the people whose mouths they were once and research departments have to use cows teeth to try and understand enamel decay. Today we got to use Nicky’s SEM to image some pre-coated teeth which have plaque build-up and extensive decay. But w-o-w were the SEM images awesome. Jakob and I started the day in our Nanoanalysis lab, where Iain showed him some atomic force microscopy (AFM) images of perovskite LEDs. AFM takes hours whilst SEM takes minutes. We argue that we like atomic force microscopy because we can reuse our samples (because they’re not scattering electrons they’re just pinging a laser beam we don’t coat them with metal), but in reality we never reuse our samples and just get a lower-resolution image. Today Jakob and I saw red blood cells, collagen fibres, plaque and enamel all within a few minutes.

Nicky also showed us her Transmission Electron Microscope (TEM). The TEM is a much bigger beast (at Imperial they have a £2.4 million Titan TEM, which is the size of a whole room). Electrons from TEMs can reach 300 keV, letting you not only image the surface of a film but get a complete chemical analysis of the molecules inside. Nicky’s microscopy suite is used by doctors, dentists, visiting scientists from UCL and Imperial and even artists. Nicky’s latest project is with restoration experts from Florence who are trying to retain their renaissance; using home-grown nanoparticles to fill the cracks in sculptures and imaging the decay of ancient canvases. On one collaboration Nicky chemically analysed some of Darwin’s diaries. She’s got an impressive publication record, phenomenal talent with a diamond knife (you try cutting teeth with an old scalpel like poor Jacob) and an incredibly personable manner.

Whilst we were in the lab, I kept forgetting Jakob was only sixteen and had AS-levels to revise for. He’s much more knowledgeable than I am about running a complicated piece of kit, he’s got a longer attention span and he’s inquisitive. With the help of Professor Becky Parker, he’s part of a new generation of young people who are embarking on an exciting scientific journey- they’re bypassing academia (i.e. constant moaning that accompanies grant/ fellowship applications and peer-reviewed journals) and doing genuine, fundamental scientific research. They make PhD students realise what fun we’re all having and senior lecturers realise that educating the next generation is more important than anything else in the world. They should make OFSTED/ Education Authorities realise quite how wrong they’re getting it with dated curricula and an overwhelming lack of respect of the teaching profession- watch this space.

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