Resurrecting dinosaurs with medical scanners and 3D printers

CT scans and 3D printers are making it possible to see fossils that were previously inaccessible inside rock.

Accurate copies of fossilised bones can now be made from the combined use of computed tomography (CT) scans and 3D printers, according to a paper published in the journal Radiology.

The technique offers scientists a non-destructive way of transporting and handling rare or fragile fossils.

To protect such specimens from damage during transportation, the fossils are often stored in plaster jackets or casts. These jackets must be strong enough to protect the fossils, but should also separate easily from the specimen when removed.

It is during the removal of the plaster and surrounding sediment that the fossil is in danger of material loss or even destruction. This typically occurs when the plaster is stuck fast to the bone.

(A 3D print of a fossil (right) next to the original still inside a plaster jacket. Image: Courtesy of Radiology and RSNA)

A group of German researchers found that, by using CT and 3D printers, they could separate fossilised bone from its surrounding sediment matrix in a way that would not harm the specimen, then produce a 3D copy of it.

Applying this method to an unidentified fossil from the Museum für Naturkunde in Berlin, the researchers scanned the bone with a 320-slice multi-detector system to show up the different attenuation (absorption of radiation) through the bone and the surrounding sediment matrix, depicting clearly the fossilised vertebra.

The scan also provided information on the condition and integrity of the specimen, like otherwise unknown fractures, and helped the researchers build an accurate reconstruction of the fossil.

Then using a laser sintering system – a process which uses high-powered lasers to fuse materials by adding thin horizontal layers of plastic – an accurate 3D copy of the fossil was produced.

(An enlarged 3D copy of a 380 million year old coelacanth skull found near Fitzroy Crossing, Western Australia. Image: John Long)

The impact on palaeontology
According to Richard Brian Gunderman, a professor of radiology at Indiana University who was not involved in the study, CT scanners are able to determine the exact structural dimensions of an object, down to fractions of a millimetre.

This data can then be used to construct a replica so precise that objects of great historical interest, like Stradivarius violins, have been created to sound remarkably similar to the originals.

“Such a technology has been a boon to palaeontologists in the past few years,” said John Long, strategic professor in palaeontology at Flinders University.

“Once we relied on meticulous time-consuming methods to prepare delicate fossils out of the rock and, even then, we could only see their external features. Now, using high-resolution micro-CT scanners and synchrotrons [particle accelerators], we can investigate every nook and cranny of the fossil right down to individual cells and tissue structures without having to risk damaging the specimen.

“Combined with advanced 3D printing, we can now slice though the ancient fossil skulls and print them in halves showing the full anatomy in clear definition. This will no doubt revitalise palaeontology.”

(A 3D scan of a 380 million-year-old Gogonasus fish skull by Tim Senden and ANU Vizlab.)

Ahi Sema Issever, from the Charité Campus Mitte in Berlin and one of the study’s authors, explained: “The most important benefit of this method is that it is non-destructive so the risk of harming the fossil is minimal. In addition, not only does this method allow for a global exchange of rare fossils in any quantity, data on the specimens can also be digitally shared between research institutes, museums and schools while protecting the original fossil.”

Darren Curnoe, associate professor at the University of New South Wales, agreed, saying: “Famous fossils like the Taung Child in South Africa - the very first ancient ape-like creature found in our human evolutionary tree - has been quite badly damaged following almost 90 years of study by scientists.

“Almost everyone who sees the fossil wants to take a couple of measurements of their own, and by doing so, is damaging these priceless pieces of our collective heritage. We need to do better, and such technology might just be the answer.”

A note of caution
Although supportive of the technological breakthrough in this study, Professor Long warned that researchers must not rely too heavily on tomographic imagery and 3D printing to draw their conclusions.

“It is important to carefully study the preservational biases of the original fossil first to determine how reliable a computer-generated image will be. In some cases, replacement of bone by other minerals or the presence of solid inclusions can effect the quality of CT images and affect 3D printing results.

“Scientists still need to study the original specimens in detail first, and then make interpretations using CT tomography and 3D printing.”

(A scanned 400 million-year-old placoderm eye capsule found in Taemas near Canberra. Image: Tim Senden)

Associate Professor Curnoe agreed, saying: “Any model made from CT scans must properly distinguish actual bone from missing bone, or even from materials like plaster, that had been used in the past to reconstruct missing bones in the fossils. This is particularly important since most fossils found are incomplete or distorted.

“In the end, there is nothing like seeing the real thing to fully understand the anatomy and the state of preservation of a fossil. But, for the sort of work many scientists do, especially postgraduate students, 3D models would be incredibly useful at a time when funding can be very hard to get.”

Beyond fossils
Some experts speculate that the findings from this study will benefit the medical field, like building and fitting implants in orthopaedic surgery. Others feel that the technique could be used to model real bones and other tissues, such as cadavers that have been preserved in ice or peat bogs.

Martin Baumers, a research fellow at the University of Nottingham, would like to see the implementation of a virtual library and data infrastructure for such 3D data and designs. He believes that it would aid collaborative research, allowing experts from different disciplines to share and retrieve 3D models for 3D printing or other scientific, even commercial, usage.

For Professor Long, the biggest breakthrough will come when palaeontologists possess the ability to make portable machines to take into the field and scan fossils, still buried under the rock layers, to determine the full extent of the fossil before excavating it.

This article was originally published at The Conversation. Read the original article.The Conversation

A scan of a 380million-year-old tooth from a fossil shark. (Image: Tim Sendon)
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Autism and gut bacteria – the surprising link between the mind and the stomach

A recent paper has found that autistic-related social patterns can be reversed when one species of gut bacteria is present in the microbiome of mice. 

Autism – a developmental disorder that causes impediments to social interactions and behaviour – is usually linked by scientists to abnormalities in brain structure and function, caused by a mix of genetic and environmental factors. Scientists have almost always attempted to understand the way autistic people process the world around them by looking to the mind.

According to the National Autistic Society, “There is strong evidence to suggest that autism can be caused by a variety of physical factors, all of which affect brain development; it is not due to emotional deprivation or the way a person has been brought up.”

Recently, however, a lesser-known link to autism has gained traction. This time, the link is not found in the brain but in the gut.

Reporting their findings in the journal Cell, researchers from the Baylor College of Medicine, Texas, found that the presence of a single species of gut bacteria in mice could reverse many behavioural characteristics related to autism.

In the digestive tracts of humans and other animals, there exists a complex, symbiotically integrated network of trillions of microorganisms known as the “gut flora” or “microflora”. The idea that all these bacteria and microorganisms have taken up a home in our gut may initially seem startling, but they serve a number of beneficial purposes, such as aiding digestion and offering immunity from infection.

The potential link between gut flora and autism arose as researchers identified the increased risk of neurodevelopmental disorders, such as autism, among children born from mothers who were obese during pregnancy. The microflora of obese people is demonstrably different from those who are not obese, and as a result, connections have been made to the gut issues often reported in autistic people.

The senior author of the study and neuroscientist Mauro Costa-Mattioli said: “Other research groups are trying to use drugs or electrical brain stimulation as a way to reverse some of the behavioural symptoms associated with neurodevelopmental disorders – but here we have, perhaps, a new approach.”

To determine what the differences in gut bacteria were, the researchers fed 60 female mice a high-fat diet, with the aim of replicating the type of gut flora that would be found among people consuming a high-fat diet which would contribute to obesity. A control group of mice was fed a normal diet to serve as comparison. The mice in each group then mated, and their eventual offspring then spent three weeks with their mothers while being observed to see how behaviour and microflora was affected.

It was found that the offspring from the mice laden with high-fat foods exhibited social impairments, including very little engagement with peers. Meanwhile, a test called ribosomal RNA gene sequencing found that the offspring of the mice that were fed a high-fat diet housed a very different bacterial gut environment to the offspring of mice fed a normal diet.

Discussing the result, co-author Shelly Buffington was keen to stress just how significant the findings were: “By looking at the microbiome of an individual mouse we could predict whether its behaviour would be impaired.”

In an effort to understand whether the variation in microbiome was the reason for differences in social behaviour, the researchers paired up control group mice with high-fat diet mice. Peculiarly, mice eat each other’s faeces, which is why researchers kept them together for four weeks. The high-fat diet mice would eat the faeces of the normal mice and gain any microflora they held. Astonishingly, the high-fat diet mice showed improvements in behaviour and changes to the microbiome, hinting that there may be a species of bacteria making all the difference.

After careful examination using a technique called whole-genome shotgun sequencing, it was found that one type of bacteria – Lactobacillus reuteri – was far less prevalent in the offspring of high-fat diet mice than the offspring of normal-diet mice.

Discussing the method and finding, Buffington said: “We culture a strain of Lactobacillus reuteri originally isolated from human breast milk and introduced it into the water of the high-fat diet offspring. We found that treatment with this single bacterial strain was able to rescue their social behaviour.”

What the Lactobacillus reuteri seemed to be doing was increasing production of oxytocin, a hormone which is known by various other names such as the “trust hormone”, or the “love hormone”, because of its role in social interactions.

The results of the experiment showing that Lactobacillus reuteri can influence social behaviour are profound findings. Though the work would need to be transferred from mice studies to full human clinical trials to see if this could be applied to autistic people, the impact of adding Lactobacillus reuteri to the gut flora of mice can’t be underestimated. It seems then, for now, that research will go with the gut.