Heart trouble? Just print off a new one

THE dream of 3D-printing whole, living human hearts for life-saving transplants just got a little closer. A team at Carnegie Mellon University in the US has developed a technique to 3D-print collagen in fine detail. This is a key step to creating replacement organs because collagen, besides being the most abundant protein in the body, is a key structural element that forms the biological scaffold that gives organs structure and strength.

The challenge in using collagen as a bio-ink is that it starts out as a fluid. The technique, called Freeform Reversible Embedding of Suspended Hydrogels (FRESH), deposits collagen, layer by layer, within a support bath of gel. This enables the collagen to solidify in place as the complex 3D structure is built up. When the printing is complete, the support gel is melted away by gently heating it to 37 degrees celsius — body temperature.

‘If you try to print this in air it just forms a puddle on your build platform. So we’ve developed a technique that prevents it from deforming,’ said team member Andrew Hudson.

The technique can print filaments as narrow as 0.02mm — around the width of a human hair. This enables researchers to print highly detailed structures into which living cells can be deposited to build muscle and blood vessels.

‘What we’ve shown is that we can print pieces of the heart out of cells and collagen into parts that truly function, like a heart valve or a small beating ventricle,’ said Prof Adam Feinberg, a biomedical engineer at the university. ‘By using MRI data of a human heart, we were able to accurately reproduce patient-specific anatomical structure and 3D-bioprint collagen and human heart cells.’

The FRESH technique will also work with other bio-inks that, like collagen, are soft when first printed, so the team hopes it will provide an adaptable tissue-engineering platform. They have made the system design open source, so other groups can use them to build low-cost, high-performance 3D bio-printers.

But Prof Feinberg says there is a long way to go before 3D printed organs are ready for use in hospitals. ‘It is important to understand that there are many years of research yet to be done,’ he said. ‘But there should still be excitement that we’re making real progress towards engineering functional human tissues and organs, and this paper is one step along that path.’

Healthy social life can reduce dementia risks

MAINTAINING social links through middle age could help lower the risks of developing Alzheimer’s.

Researchers at University College London analysed data from patients from 1985 to 2013 showing how often they saw friends and relatives. This was checked against health records for dementia diagnoses.

The team found those that saw loved ones almost daily at the age of 60 were 12 per cent less likely to develop dementia than someone who only saw one or two friends every few months.

‘Spending more time with friends could be good for mental wellbeing, and may correlate with being physically active, both of which can reduce the risk of developing dementia,’ said study author Prof Gill Livingston.

There are around 850,000 people living with dementia in the UK, and the Alzheimer’s Society estimate it may soar to more than 2million by 2051. There is currently no cure.

Mind how you glow… secret of sharks revealed

SCIENTISTS have deciphered the secret of how glow-in-the-dark sharks light up in the ocean depths.

Researchers have known for a while that invertebrates such as corals and jellyfish can fluoresce thanks to special proteins in their bodies but until now they had not figured out exactly how sharks do it.

Researchers from City University of New York and Yale University studied swell sharks and chain catsharks, which live at depths of 1,500ft and fluoresce with a bright green colour.

They found the lighter-coloured areas of skin contained a new type of fluorescent molecule. It may help sharks recognise each other and have antibacterial protection against infection. Harnessing the fluorescent abilities could help develop imaging systems for science and medicine.

Quick way to get fat? Pass fast food outlet on daily commute

PASSING fast food outlets on your daily commute could make you fatter. A study of 710 New Orleans primary school teachers looked at the impact of food availability on their way to work on body mass index. Teachers that came near fast food outlets had higher BMIs than those passing ‘slow’ table service restaurants as they had more opportunity for ‘a quick and unhealthy meal’, Arizona State University found.

Using gender-neutral language could lead to greater equality

USING gender-neutral pronouns instead of gender-specific ones such as ‘he’ or ‘she’ can promote equality, new research says.

In a 2015 Swedish study, people asked to use gender-neutral pronouns to describe a cartoon of a non-gendered figure were less likely to give a male name to another fictional character than those who used masculine pronouns. It suggested a reduction in mental bias towards males.

■ 110% — The amount butterfly numbers are up in England compared to 2017 figures.

■ 353million — The number of trees planted in Ethiopia in a single day in an attempt to combat the effects of deforestation and climate change.


Do giraffes make a noise?

While not the most talkative of animals, giraffes snort or hiss when threatened, and mothers bellow to their young. But we recently found they make other noises. In 2015, researchers analysed recordings of giraffes from zoos in Berlin, Copenhagen and Vienna, and found they make low-frequency humming sounds at night. It’s thought these are a ‘contact call’ between giraffes separated from the herd, so they can find each other in the dark. But another theory suggests the humming is actually snoring or sleep-talking!

Why don’t hailstorms last as long as rainstorms?

Hail is produced during thunderstorms, when an updraft of air — caused by a warm air mass meeting a cold one — carries tiny droplets of water upwards. The droplets freeze at high altitude, and the resulting ice crystals grow until they are too heavy to stay suspended. Hail only forms in the narrow region where the two air masses meet, so it falls over a small strip of land. The high-energy storms tend to move fast, so someone on the ground experiences them as a short burst. As they need a supply of warm, moist air, hailstorms quickly run out of energy and dissipate.

Based on stories featured in BBC Science Focus magazine. Head to sciencefocus.com/metro for the latest science news and a special subscription offer for Metro readers.

Also in BBC Science Focus this month:

■ What could alien life look life?

■ Cutting carbs could be good for your brain

■ Can planting more trees get us to carbon neutral?

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