Miniature labs, quantum computing, and the dangers of sweeteners
Chemistry, Biology, Physics: Three scientists talk through big recent developments in their fields.
This article is a preview from the Winter 2014 edition of New Humanist. You can find out more and subscribe here.
Chemistry - Mark Lorch
Most people have a good idea of what a chemistry lab looks like; test tubes, beakers filled with bubbling fluids, lab coats. But there’s a whole branch of chemistry, known as lab-on-a-chip, which looks nothing like this. Instead of the benches and fume cupboards, these labs can be tiny, centimetre-sized chips of glass, riddled with channels and chambers just a few millionths of a metre (micrometres) across, which allow chemicals to be mixed. The aim is to distil the essence of the traditional lab and miniaturise it, allowing chemistry to be easily conducted by non-chemists. In a sense, lab-on-a-chip is doing for chemistry what the microchip did for computers: turning it from the domain of specialists to a useful tool for anyone.
A lab-on-a-chip is being developed for scene-of-crime DNA fingerprinting, which could return a result in minutes instead of days; for blood tests carried out by the GP; and for environmental monitoring. It’s already used in diabetics’ blood-sugar monitors and pregnancy tests, which quickly test the chemistry of bodily fluids.
The myriad possible applications for lab-on-a-chip technology is regularly recounted in numerous journals, including one called, not surprisingly, Lab-on-a-Chip. In one recent study of underground oil reservoirs, a scientist manufactured a chip made from rock normally found around oil deposits, then studied the effect that chemicals used in oil extraction had on the device. The channels carved in the rock are a good and controllable representation of the conditions found during oil exploration.
Or if you want something really simple, how about getting rid of the glass or rock chips and doing the chemistry on paper instead? New techniques, also reported in Lab-on-a-Chip, describe the formation of 80 micrometre channels on paper. The paper is coated with a compound that becomes a polymer (like a plastic) when exposed to light. Then, with extremely fine lasers, the researchers manage to construct minuscule channels. The result is an extremely quick and cheap way of constructing chips that could, soon, bring a chemistry lab to your home.
Mark Lorch lectures in Chemistry at Hull University
Biology - Lydia Leon
How do you satisfy a sweet tooth and stay healthy? For the last century, the answer appeared to be non-caloric artificial sweeteners (NAS), such as saccharin and aspartame. These additives are used prolifically in food and drink. It’s a simple idea: replace sugar with NAS, consume fewer calories, lose weight. And that’s not the only benefit – NAS are also meant to prevent a rise in blood glucose after eating, particularly risky for overweight or diabetic people.
NAS are endorsed by governments across the world. But research into their effects has been contradictory. A study published last week in the journal Nature presents the strongest data yet to challenge their apparent benefits.
Scientists observed the effects of NAS on glucose metabolism in mice. Mice were fed a NAS-rich diet for 11 weeks, at levels equivalent to “commercial use”. They developed noticeable glucose (sugar) intolerance – a symptom of type-2 diabetes in humans. Mice fed diets with the same quantities of glucose or water showed much lower glucose intolerance – indicating a healthier metabolic state, even though they ate more sugar. You’d expect the opposite from a product used for weight loss and diabetes management.
The scientists suggested the difference might have been due to changes in gut bacteria. Mice that consumed NAS had a very different gut microbiome (a microbiome is a combination of bacterial species) from the group that consumed glucose. This observation is backed up by other recent studies, where different species and activity of gut bacteria were found between obese and non-obese people, and those most at risk of metabolic diseases and cancers.
So does NAS consumption make you more likely to be glucose intolerant or diabetic? It’s not that clear cut; nutritional and microbiome data are notoriously tricky to interpret. And, as with any surprising results, the experiments must be replicated. But if the evidence does mount that NAS has the opposite effect to those widely advertised, shockwaves will be sent from your can of diet fizz through the boardrooms of food giants and health services across the world.
Lydia Leon is a PhD student at University College London
Physics – Rory Fenton
This October, as the eyes of the world were trained on California for the latest smartphone announcement (if you missed it: it’s slightly bigger), the truly exciting technology news was announced in Australia. Physicists at the University of New South Wales had made a major step towards a whole new type of computer.
The quantum computer was first proposed in the early ’80s by applying quantum mechanics, laws normally most relevant at the scale of electrons and other tiny particles, to computing. A “classical” computer, like the one I’m writing this on, performs calculations using codes made up of a series of 1s and 0s. Each 1 or 0 is known as a “bit”. A fundamental idea of quantum mechanics is that a particle can be in more than one state at a time. A quantum computer takes advantage of this by having each bit take on both 1 and 0 at once. While a classical computer might have a string of bits like “001”, a quantum computer could use the same number of bits (now called “qubits”) to express “001, 010, 100, 110, 011, 111, 000 and 101” at the same time: in other words, every possible combination of those three bits. A quantum computer could then perform multiple calculations at once, rather than doing them one by one. This would mean much faster computers, and a whole new type of programming. It could also see the most advanced encryption systems in the world become obsolete.
To date, quantum computers have only been made to perform very basic calculations, such as the 2007 Canadian D-Wave, which can solve Sudoku puzzles. Quantum states tend to “collapse” when they interact with their surroundings, making them very unreliable. The announcement in New South Wales came after an experiment in which physicists achieved a record-smashing 99.99 per cent accuracy from their qubits. Having achieved such high accuracy, the next stage will be combining these accurate qubits to build a functioning computer. Don’t expect a qPhone anytime soon – these machines are still very much confined to university labs for now – but with such leaps we’ve never been closer to a fully functioning quantum computer.
Rory Fenton studied theoretical physics at Imperial College