Excuse the slight off (chemistry) topic post, but I wanted to let folks know about a crowdfunded science anthology I’ve launched via Unbound.
You don’t need a PhD in horology to know that there are piles of great popular science books out there and not enough time to read them all. So I’ve collected a bunch of the best established and emerging science writers – people working at the cutting edge of their own particular disciplines – and asked them to distil their passions into just one chapter each.
The result is Great Explanations, an anthology of the most pressing, fascinating and sometimes just plain overlooked topics from the far reaches of science, engineering and maths topped with a smattering of the philosophy and history of science. These are the subjects that working scientists are most passionate about, or interested in, or surprised by, in their own disciplines – the things they think curious general readers really ought to know.
We’ve also teamed up with Sense about Science, which promotes the public interest in sound science and evidence. Some of the contributing authors are part of their Voice of Young Science network and 15% of the book’s profits will be donated to the charity.
Contributors include:
Astronomer Royal, and 60th President of the Royal Society, Lord Martin Rees
Sir David John Spiegelhalter OBE FRS, Winton Professor for the Public Understanding of Risk at the University of Cambridge, and author of Covid by numbers, making sense of the pandemic with data.
Prof Adam Hart, entomologist and the University of Gloucestershire’s Professor of Science Communication.
A whole load more fabulous scientists and writers will be revealed over the next few weeks; stay tuned to our updates to be among the first to find out more.
Of course, if it doesn’t get funded the book will never exist, so pop over to Unbound and pledge!
Chemistry built the modern world, from the materials that make up the everyday objects around us, the batteries in our devices and cleaning products that help to maintain sanitation. All this and much more besides are examples of chemistry in everyday life.
To illustrate this and have a bit of fun along the way we (Phil Bell-Young, the Salter’s Institute for Chemistry and I) put together a demonstration packed show called ‘The Periodic Dinner Table’.
It is a cross between demo lecture, comedy sketch and a game of bingo played on a periodic table. Just watch the video, and when you spot us interacting with an element cross it off on your periodic table (here’s one specially adapted for the show).
From the simplest bacteria to humans, all living things are composed of cells of one type or another. Amazingly, no matter where on the evolutionary tree they perch, those organisms all have fundamentally the same chemistry. This chemistry must provide mechanisms that allow cells to interact with the external world, a means to power the cell, machinery to carry out all the varied processes, a structure within which everything runs, and of course some sort of governance. Cells, in many ways, are like communities, but controlled and governed through a web of interlocking chemical reactions. Biochemistry is the study of those reactions, the molecules that are created, manipulated, and destroyed as a result of them, and the massive macromolecules (such as DNA, cytoskeletons, proteins and carbohydrates) that form the chemical machinery and structures on which these biochemical reactions take place.
Or, put more succinctly by the great physicist Erwin Schrödinger,
‘In biology .. a single group of atoms .. produces orderly events marvellously tuned in with each other and the environment according to the most subtle laws.’
Biochemistry is then the endeavour to understand those subtle laws governing those finely tuned orderly events, it is the study of biological molecules and their interactions, and so aims to reveal the molecular basis of life.
Of course, life in all its glory is so much more than just single cells. Cells come together to form multi-cellular organisms which then require a means for individual cells to communicate and ‘trade’ with one another. The organisms, in turn, interact to form the complex webs that are our eco-systems. And all of those interactions are modulated and facilitated through biochemical means. For example, consider the rhodopsin molecules that respond to photons of light, and so act as the first stage of a predator spotting its next meal. Or the olfactory proteins that bind a few minuscule molecules, which trigger a cascade of biochemical reactions that result in prey being alerted to the predator’s presence. Or the antibodies that act as the first guards, recognising the foreign molecules of an invading parasite and triggering the army that is the immune response. All of these processes fall within the realm of biochemistry.
It didn’t take long for an understanding of the chemistry of life to turn into a desire to manipulate it. Drugs and therapies all aim to modify biochemical processes for good or ill: Penicillin, derived from a mould, stops bacteria making their cell walls. Aspirin, with its origins in willow bark, inhibits enzymes involved in inflammatory responses. A few nanograms of botulinum toxin (botox), can kill by preventing the release of neurotransmitters from the ends of nerves and so leads to paralysis and death. Alternatively, the same botulinum toxin administered in tiny quantities results in a wrinkle free forehead. This is all biochemistry.
Detailed description of these topics could easily have made it into this book, and some readers may feel I was remiss in neglecting them and other topics as fundamental as vitamins, hormones, chromosomes, and numerous biochemical techniques. But this is after all a very short introduction, and so I had to draw the line somewhere. As a result, for much of the book I’ve focussed on some of the chemistry that occurs within cells. For therein lie the fundamental chemical processes that all life shares.
Finally, the boundaries of biochemistry are ill defined; it overlaps with genetics, molecular biology, cell biology, biophysics and biotechnology. And so I finish with a pair of chapters which explore how fundamental discoveries in biochemistry are influencing these fields and society at large.
Transitioning to home working had its challenges for us all, but when your job involves researching biological applications for nanotechnology, those trials are a little more complicated than juggling the household’s broadband usage. So barred from his lab, you might reasonably expect the research by organic chemist Vittorio Saggiomo, from the Bionanotechnology group at Wageningen University & Research in the Netherlands, to have come to a grinding halt.
But Saggiomo is a creative, imaginative type, and so he began to wonder if he could turn common household appliances to good use in the fight against COVID-19. More specifically, could he create a cheap, highly sensitive home test for the virus? It turns out he could. His team has now posted the idea on a preprint server, ChemArxiv. The paper is yet to be reviewed by other scientists.
At the moment, there are two main types of COVID-19 test: the PCR test and the lateral flow test (LFT). The gold-standard PCR test checks for the presence of the virus by detecting its genetic material known as RNA. But there are vanishingly small amounts of viral material in a swab, so the material has to be converted into DNA and amplified before it can be detected. And this is achieved by the “polymerase chain reaction”, which is what PCR stands for.
The process involves repeated cycling through a range of temperatures between 50°C and 90°C. During each cycle, the amount of DNA doubles, so after 30 cycles over a billion copies of the viral material can be created from just one strand of starting material. The amplified material is then detected with fluorescent labels that attach themselves to the viral DNA sequences.
As such, PCR is a highly sensitive technique, but it needs specialist materials and equipment to perform. This is why the tests are sent off to a lab, and it takes a day or two to get the result.
The second common test is the lateral flow test (LFT). These work by detecting fragments of viral protein shells. Embedded within the strips of the LFTs are antibodies that bind to the virus. These antibodies are labelled with tiny gold particles, which appear red, allowing you to see them on the test device. The labelled antibodies accumulate on distinct bands on the LFT depending on whether the virus is present or not.
The LFTs are fast, cheap and easy to use, making them ideal for community and home testing. But they are nowhere near as sensitive as the PCR tests – they will only identify people with high viral loads. This means many people who are infected will get a false negative result from such tests.
CoroNaspresso tests
Ideally, we need a home test that’s as easy to use as the LFTs but as sensitive as the PCR test. An excellent candidate is a method called loop-mediated isothermal amplification (Lamp). This works along very similar principles to PCR, producing multiple copies of the starting genetic material – which you can get from a swab – but has some key advantages.
For example, it can be combined with a handy “colour readout”. When the Lamp reaction occurs, it causes an increase in the acidity of the sample. That means you can add a substance that changes colour according to pH value in the reaction mix, providing a visual indication of a positive or negative result. Another advantage is that Lamp reactions are carried out at a fixed temperature (about 65°C) instead of needing constant cycling through a range of temperatures.
Nevertheless, Lamp still needs fine temperature control. Temperature control systems – be they in a PCR machine, a Lamp instrument or household oven – are usually achieved with electronic thermostats. However, making and shipping new electronic devices specifically designed for home Lamp tests is impractical (especially in the middle of a pandemic). So Saggiomo tried to find a way around this. He hit upon substances called phase change materials that absorb energy (heat) as they melt and so maintain a constant temperature.
After finding a wax made of such a material that melted at exactly the required temperature, Saggiomo set about constructing a device to house the Lamp reaction tubes and chunks of wax. This then needed to be inserted into some other material that could be heated. The perfect housing turned out to be staring him in the face while making his morning coffee: Nespresso coffee machine capsules.
The final step was just finding the right way to heat the capsules. After trying the dishwasher (it worked but samples kept getting lost), the microwave oven (failed, because the tubes overheated and lids popped off) and cups full of hot water (not enough control on the temperature), Saggiomo settled on a simple pan of simmering water on a stovetop. The resulting “CoroNaspresso” device, when tested by other members of the team, with swabs from six people, correctly identified three cases of COVID-19 (these had a different colour to the negative tests).
Home covid test. Tweet by @V_Saggiomo
The test, including the capsules, phase changing wax and vials in which to insert genetic material, would be easy to produce in millions. People could then swab for genetic material at home and heat the capsules to get their results. These devices are also cheap (about €0.20), easy to make, easy to use and largely recyclable. Maybe we’ll see the CoroNespresso tests in our homes soon, just don’t get them confused with your regular coffee pods.
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