Fighting the flu, a breakthrough on HIV treatment, and the uses of carbon
Chemistry, Biology, Physics: Three scientists talk through big recent developments in their fields.
This article is a preview from the Summer 2017 edition of New Humanist. You can find out more and subscribe here.
Physics – Ceri Brenner
It’s the key component of all living things. When bonded with hydrogen you get plastic and oil, or sugar and alcohol. Bonded with two parts oxygen, you have the air that you’re breathing out right now. Bonded with one part oxygen and it will kill you in your sleep. And by itself, the atoms can be arranged in a variety of lattice structures so that it appears in many forms, or allotropes: the graphite in your pencil, the charcoal on your barbecue, the diamond in your jewellery. Carbon is a wondrous element.
The single-atom-layer allotrope of carbon, graphene, regularly makes it onto the news – for good reason. It’s ultra-lightweight, almost transparent, and the world’s best conducting material. It’s also 200 times stronger than steel but 1 million times thinner than human hair. It has the potential to revolutionise all sorts of technologies When a sheet of graphene is rolled up it’s known as a single-walled carbon nanotube. Recently, researchers at the Rochester Institute of Technology formed thin papers of carbon nanotubes and demonstrated that they can be used and reused for water filtration: a sustainable alternative to current single-use options. University of Manchester scientists also reported recently on their demonstration of using graphene-oxide as a sieve for removing salt from seawater, making it drinkable, therefore opening up avenues for compact and accessible filtration technologies.
A recent paper from a Taiwanese group has shown that the heat conductivity of a carbon nanotube increases with increasing tube length. Call the physics police! This breaks the law – Fourier’s law in thermodynamics, which says heat conductivity is a property of the material and independent of shape. But nanostructures that are one atom thick don’t obey our macro-world rules of physics. Their work proves that carbon nanotubes are an excellent candidate for taking heat out of electronics and computer chips to greatly improve their performance.
The applications are so versatile and we’re only just getting started with graphene. Hooray for carbon.
Ceri Brenner is a physicist who works for the Science and Technology Facilities Council
Chemistry – Mark Lorch
Influenza is never pleasant. But for some, particularly young children, pregnant women and the elderly, complications from flu can lead to serious and life-threatening illness. Vaccinations help to control the spread of the disease and reduce the severity of symptoms, but these are just one line in the defence against a potentially fatal illness. Once flu has been diagnosed, treatment with antiviral drugs can help. But for these to be effective they need to be administered fast. The problem is that flu isn’t always easy to diagnose. Clinical tests are slow, expensive and have low sensitivities. What a GP needs is a quick, cheap and effective way to test a patient at risk of complications from flu.
A team from Georgia State University may have created just such a test, by adapting technology that is already used by diabetics to check their blood-sugar levels. The test actually checks for the presence of a protein called glycoprotein neuraminidase. This covers the surface of the virus and is a key tool that the flu uses to release itself from infected cells. In effect, the neuraminidase helps the flu to cut its way out of a cell. The team designed a compound that the neuraminidase binds to, then cuts into two pieces, one of which is a sugar called galactose. In the absence of the virus the new molecule obviously remains intact. But when the virus is present the galactose can be easily detected with glucose monitors used by diabetics. The whole test requires only a nasal swab, a test-strip and monitoring equipment that doctors are already familiar with. Results take just 15 minutes.
The system can also be used to check on the effectiveness of some antiviral drugs. Zanamvir works by blocking neuraminidase on the surface of the flu, so stopping it from escaping from infected cells. When zanamvir was added to the new flu test it stopped the neuraminidase protein from generating galactose, which in turn meant that the drug would be effective against the virus.
This new test could well be a cost-effective, simple and powerful tool to aid the annual fight against a common and dangerous bug.
Mark Lorch lectures in chemistry at Hull University
Biology – Lydia Leon
Antiretroviral therapy for HIV is a major achievement of modern medicine. Where it is available, it transforms a diagnosis from a death sentence to a chronic, manageable disorder with almost normal life expectancy. But treatment is life-long – if patients stop taking ART, the virus always recurs, even amongst those who have undetectable viral loads during treatment.
The virus’s capacity to resurge is due to a small proportion of HIV-infected T-cells that remain dormant and inactive as a “latent reservoir” during antiretroviral therapy. Because these drugs only target cells that are actively copying viral DNA, the latent population evades detection. Targeting this stubborn, silent source of infection has long been top of the wish list for HIV researchers.
In March, a paper in Nature outlined a potentially game-changing discovery in the search for these elusive cells. The authors looked for differences in the expression of genes between infected and non-infected latent T-cells, hoping to find ways of identifying their presence. They found that 106 genes were more active in the latently infected cells. Of these, 13 were membrane-receptors that protrude from the cell surface, acting as a sort of docking station for surrounding cells or molecules. These can be easily exploited in the lab to isolate cells for further research.
The gene that showed the biggest difference between uninfected and infected latent populations encodes a membrane-receptor called CD32A. Although it did not tag the entire latent reservoir, on average it was observed on the cell surface of over 50 per cent of the latently infected population – making it an impressively powerful marker.
The research has been greeted with cautious excitement. Patents have already been filed for the diagnostic and therapeutic use of CD32A – although more research is needed to see whether it works across demographics and disease stages. The fact remains that if replication experiments mirror these results, this could be a huge step towards a cure for HIV.
Lydia Leon is a research associate in women’s health at Kings College London and University College London