Chemists create 'world's thinnest spaghetti'

The world’s thinnest spaghetti, about 200 times thinner than a human hair, has been created by a research team led by University College London (UCL). But don’t break out the pasta sauce just yet, as the aim of the work is to create extremely thin strands of material, called nanofibres, for use in medicine and industry.

As noted by study co-author Professor Gareth Williams, from the UCL School of Pharmacy, nanofibres made of starch — produced by most green plants to store excess glucose — show potential for use in wound dressings as they are very porous, allowing water and moisture in but keeping bacteria out.

“In addition,” he said, “nanofibres are being explored for use as a scaffold to regrow tissue, as they mimic the extracellular matrix — a network of proteins and other molecules that cells build to support themselves.”

Study co-author Dr Adam Clancy, from UCL Chemistry, said that starch is a promising material to use as it is abundant and renewable — it is the second largest source of biomass on Earth — and it is also biodegradable, meaning it can be broken down in the body. But it also has to be extracted from plant cells and purified, requiring much energy and water. A more environmentally friendly method would be to create nanofibres directly from a starch-rich ingredient like flour, which is the basis for pasta.

The researchers have now shown how to make spaghetti just 372 nm across using a technique called electrospinning — in which threads of flour and liquid are pulled through the tip of a needle by an electric charge — with their results published in the journal Nanoscale Advances. The next thinnest known pasta, made by hand by a pasta maker in the town of Nuoro, Sardinia, is estimated at about 400 µm wide — 1000 times thicker than the new electrospun creation.

“To make spaghetti, you push a mixture of water and flour through metal holes,” Clancy said. “In our study, we did the same except we pulled our flour mixture through with an electrical charge. It’s literally spaghetti but much smaller.”

In electrospinning, the needle in which the mixture is contained and the metal plate upon which the mixture is deposited form two ends of a battery. Applying an electrical charge makes the mixture complete the circuit by streaming out of the needle on to the metal plate. Electrospinning using a starch-rich ingredient such as white flour is more challenging than using pure starch, as the impurities — the protein and cellulose — make the mixture more viscous and unable to form fibres.

The researchers used flour and formic acid rather than water, as the formic acid breaks up the giant stacks of spirals (or helices) that make up starch. This is because the layers of helices stuck together are too big to be the building blocks of nanofibres. The formic acid then evaporates as the noodle flies through the air to the metal plate.

While each resulting strand of ‘nanopasta’ is narrower than some wavelengths of light, and so cannot be clearly captured by any form of visible light camera or microscope, the pasta was ultimately formed into a mat of nanofibres about 2 cm across. Using a scanning electron microscope, the team scanned the mat with a focused beam of electrons and created an image based on the pattern of electrons that are deflected or knocked off.

“We’ve shown that a simpler way to make nanofibres using flour is possible; the next step would be to investigate the properties of this product,” Clancy said. “We would want to know, for instance, how quickly it disintegrates, how it interacts with cells, and if you could produce it at scale.”

Williams added: “I don’t think it’s useful as pasta, sadly, as it would overcook in less than a second, before you could take it out of the pan.”

Images courtesy of Beatrice Britton and Adam Clancy.