High voltage: Hinkley power stations near Bristol. Photo: Getty
Show Hide image

Path of least resistance: the quest for room-temperature superconductors

Michael Brooks’s Science Column. 

We don’t talk enough about superconductors. These materials carry electricity without losing energy and could change the world – if only we could rediscover the kind of progress we used to make in this field.

We have known about superconductors since 1911, when the first one was discovered. In normal conductors – an aluminium wire at room temperature, for instance – electrons move through the material, jostled by all the other particles. Cool that aluminium down to -272° Celsius, though, and it becomes a superconductor. The electrons encounter no resistance, zipping along the wire as if they were the only particles in town.

That is significant: the copper cables used to transmit electricity from power stations to your home lose 10 per cent of energy through electrical resistance. If those cables were made of a superconductor, no energy would be lost. We would not need to generate so much power, reducing our dependence on fossil fuels.

Even better would be the ability to store energy. Renewable sources such as wind, wave and solar power generate energy at times and rates beyond our control. That power could be stored indefinitely in superconducting circuits. Because these don’t dissipate any of the energy, a superconducting power store is a battery whose charge lasts as long as you need it to.

There are also transport applications. Superconductors repel magnets and engineers have exploited this by putting superconductors on trains and electromagnets on the track. The repulsion levitates the train above the track, hugely reducing friction and clearing the way for ultra-fast transport.

So far, though, magnetic levitation trains have taken off in only a couple of places around the world. That is because superconductors are still not super enough. The main problem is that more energy is spent to cool materials until they become superconducting than is saved through reduced transmission loss, better energy storage capacity or greater transport efficiency.

This is a tale of dashed hopes. From 1911 to the 1980s, superconductors were available at temperatures below -240° Celsius only. We thought we had beaten this barrier in 1986 when we discovered a copper compound that was superconducting at -183° Celsius. Suddenly, things were looking up: we could turn materials superconducting by cooling them with liquid nitrogen, a relatively cheap and easy means of refrigeration.

However, it still wasn’t cheap and easy enough to make superconducting technology mainstream. So we cooked up more of these “high-temperature superconductors”. By 1993, we had got to about -140° Celsius. Things were looking very good indeed. And then, almost nothing. We are still less than halfway to room-temperature superconductors.

That’s because, despite decades of research, we’re still trying to figure out how they work. Progress is painfully slow. In October, French and US researchers finally confirmed a prediction, made in 1964, about one microscopic characteristic of what is going on inside superconductors.

This latest breakthrough might lead to superconductors that can withstand higher magnetic fields and thus give hospitals better MRI scanners – but it won’t push that critical transition point up towards room temperature. We can only hope that will be achieved by the researchers investigating other features of superconduction. No one thinks such a breakthrough is imminent. In an age when we have come to understand some of the deepest secrets of the universe, the secrets of the superconductor are keeping our feet firmly on the ground. 

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 13 November 2014 issue of the New Statesman, Nigel Farage: The Arsonist

Getty Images/ Staff
Show Hide image

The answer to the antibiotics crisis might be inside your nose

The medical weapons we have equipped ourselves with are losing their power. But scientists scent an answer. 

They say there’s a hero in everyone. It turns out that actually, it resides within only about ten percent of us. Staphylococcus lugdunensis may be the species of bacteria that we arguably don’t deserve, but it is the one that we need.

Recently, experts have cautioned that we may be on the cusp of a post-antibiotic era. In fact, less than a month ago, the US Centres for Disease Control and Prevention released a report on a woman who died from a "pan-resistant" disease – one that survived the use of all available antibiotics. Back in 1945, the discoverer of penicillin, Alexander Fleming, warned during his Nobel Prize acceptance speech against the misuse of antibiotics. More recently, Britain's Chief Medical Officer Professor Dame Sally Davies has referred to anti-microbial resistance as “the greatest future threat to our civilisation”.

However, hope has appeared in the form of "lugdunin", a compound secreted by a species of bacteria found in a rather unlikely location – the human nose.

Governments and health campaigners alike may be assisted by a discovery by researchers at the University of Tubingen in Germany. According to a study published in Nature, the researchers had been studying Staphylococcus aureus. This is the bacteria which is responsible for so-called "superbug": MRSA. A strain of MRSA bacteria is not particularly virulent, but crucially, it is not susceptible to common antibiotics. This means that MRSA spreads quickly from crowded locations where residents have weaker immune systems, such as hospitals, before becoming endemic in the wider local community. In the UK, MRSA is a factor in hundreds of deaths a year. 

The researchers in question were investigating why S. aureus is not present in the noses of some people. They discovered that another bacteria, S. lugdunensis, was especially effective at wiping out its opposition, even MRSA. The researchers named the compound created and released by the S. lugdunensis "lugdunin".

In the animal testing stage, the researchers observed that the presence of lugdunin was successful in radically reducing and sometimes purging the infection. The researchers subsequently collected nasal swabs from 187 hospital patients, and found S. aureus on roughly a third of the swabs, and S. lugdunensis on up to 10 per cent of them. In accordance with previous results, samples that contained both species saw an 80 per cent decrease of the S. aureus population, in comparison to those without lugdunin.

Most notably, the in vitro (laboratory) testing phase provided evidence that the new discovery is also useful in eliminating other kinds of superbugs, none of which seemed to develop resistance to the new compound. The authors of the study hypothesised that lugdunin had evolved  “for the purpose of bacterial elimination in the human organism, implying that it is optimised for efficacy and tolerance at its physiological site of action". How it works, though, is not fully understood. 

The discovery of lugdunin as a potential new treatment is a breakthrough on its own. But that is not the end of the story. It holds implications for “a new concept of finding antibiotics”, according to Andreas Peschel, one of the bacteriologists behind the discovery.

The development of antibiotics has drastically slowed in recent years. In the last 50 years, only two new classes of this category of medication have been released to the market. This is due to the fact almost all antibiotics in use are derived from soil bacteria. By contrast, the new findings record the first occurrence of a strain of bacteria that exists within human bodies. Some researchers now suggest that the more hostile the environment to bacterial growth, the more likely it may be for novel antibiotics to be found. This could open up a new list of potential areas in which antibiotic research may be carried out.

When it comes to beating MRSA, there is hope that lugdunin will be our next great weapon. Peschel and his fellow collaborators are in talks with various companies about developing a medical treatment that uses lugdunin.

Meanwhile, in September 2016, the United Nations committed itself to opposing the spread of antibiotic resistance. Of the many points to which the UN signatories have agreed, possibly the most significant is their commitment to “encourage innovative ways to develop new antibiotics”. 

The initiative has the scope to achieve a lot, or dissolve into box ticking exercise. The discovery of lugdunin may well be the spark that drives it forward. Nothing to sniff about that. 

Anjuli R. K. Shere is a 2016/17 Wellcome Scholar and science intern at the New Statesman