Tag Archives: keratin

Recycled wool turned into memory textile that always remembers its shape

Although it is possible to shape your hair either by straightening or curling, the moment it touches water, the hair will return to its original shape. By exploiting this property, researchers at Harvard University have devised a wool-based material that has hair-like shape memory, which might inspire a new generation of textiles and smart, one-size-fits-all clothing that stretches or shrinks based on a person’s measurements.

3-D printed keratin sheet returns to its pre-programmed origami star shape when bathed in water. Credit: Harvard University.

The secret to hair’s shape memory is keratin, a fibrous protein arranged in a chain of hierarchical structures. One single chain of keratin is itself arranged in a spring-like structure known as the alpha-helix. When two of these chains twist together, they form a coiled-coil structure. Many of these latter structures are assembled into protofilaments, before eventually joining together to form large fibers of hair.

This arrangement of the alpha-helix and connective chemical bonds is one of the reasons why hair is as strong as steel. It also explains the shape memory of the hair strand: when fibers are exposed to a particular stimulus, such as heat from a hair straightener, the spring-like structures uncoil. The fibers will coil back into their original shape when triggered by a new stimulus, such as water.

Engineers at Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) found these characteristics very appealing. They extracted keratin from leftover Agora wool from textile manufacturing, which they then incorporated into a 3-D printable, biocompatible material.

To program a particular shape in the material’s memory, a solution of hydrogen peroxide and monosodium phosphate was employed. The sheet of 3-D printed, recycled keratin can then be molded into any desired shape until triggered to return to its original design.

For instance, one such keratin sheet was programmed to fold into a complex origami star as its original shape. The keratin star was then bathed in water, becoming malleable. The unfolded sheet was then rolled into a tight tube. Once the sheet dried, it was locked into a functional tube. But when the tube was put back in water, it unrolled and folded back into the origami star.

“With this project, we have shown that not only can we recycle wool but we can build things out of the recycled wool that have never been imagined before,” said Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at SEAS and senior author of the paper. “The implications for the sustainability of natural resources are clear. With recycled keratin protein, we can do just as much, or more, than what has been done by shearing animals to date and, in doing so, reduce the environmental impact of the textile and fashion industry.”

According to Parker and colleagues, these keratin sheets can be employed in a vast range of applications, from textile to tissue engineering. Imagine brassieres whose cup size and shape can be molded and shaped every day to fit a person’s needs and measurements, for instance.

 “We are continuing to reimagine textiles by using biological molecules as engineering substrates like they have never been used before,” Parker said.

The findings appeared in today the journal Nature Materials.

A western lowland gorilla goes eye-to-eye with the camera. (c) National Geographic

Gorillas are more related to humans than previously thought, complete genome sequence shows

A western lowland gorilla goes eye-to-eye with the camera. (c) National Geographic

A western lowland gorilla goes eye-to-eye with the camera. (c) National Geographic

Researchers have completed the great apes family’s genetic library after they sequenced the genes of a western lowland gorilla, joining the already-sequenced genomes of humans, chimpanzees and orangutans. Scientists found that gorillas, which share 98% of their genes with humans, are a lot more related to humans than previously thought, as well as surprising genetic differences which went unnoticed until recently.

“Previously, people had some sort of picture based on … probably one percent of the whole [gorilla] genome. So we now have a complete picture,” said study co-author Richard Durbin, a geneticist with the U.K.’s Wellcome Trust Sanger Institute.

“Based on the comparisons between them, it helps us explore the evolutionary origins of humans and where we separated from other great ape species in Africa between six and ten million years ago,” Durbin said.

The first step was taken in 2008, when the researchers sampled DNA from Kamilah, a 30-year old female western lowland gorilla, who was born in captivity and now lives at the San Diego Zoo Safari Park. Four years later, the researchers presented the complete genome, as seen published in this Wednesday edition of the journal Nature.

Gorillas – our close cousins

Their results show gorillas are are closer to humans than some might have thought. All of the members of the hominids family are considered to have descended from a common ancestor, some 10 million years ago. Around that time, human-chimp line split from the gorilla line, despite this however the team detected groups of gorilla genes that were surprisingly similar to human genes.

“Although [70 percent] of the human genome is indeed closer to chimpanzees, on average, a sizable minority of 15 percent is in fact closer to gorillas, and another 15 percent is where chimpanzees and gorillas are closest,” said geneticist Aylwyn Scally, a study co-author also at the Wellcome Trust.

The new data shows that humans and gorillas are 98% genetically identical – most of our genes are very similar, or even identical to, the gorilla version of the same gene. However, there are few important differences which have been observed.

Insightful genetic differences

Some illuminating genetic differences have been found by the researchers. For instance, certain genes involved in sperm formation have become inactive or have been reduced in the gorilla genome compared with the human genome. This trait has been probably developed by humans in consequence of severe mating competition. Gorilla packs however most often include only one male and several females.

A common sight is that of gorillas walking with the help of their arms, basically stepping on their fists. The researchers discovered gorillas possess a gene that helps the animal’s skin grow a tough layer of keratin, a protein found in hair and nails. This genes, the scientists suggest, lead to the development of tough knuckles.

What’s maybe the most interesting and valuable piece of information discovered thus far by the researchers is that of certain genes shared by gorillas and humans that cause disease in our species, but not in our ape cousins. Some variants are linked to dementia and heart failure in humans, and are shared by both humans and gorillas, however the latter seem to be unaffected by the conditions. Future research sparked by this find might show promising medical applications.

“If we could understand more about why those variants are so harmful in humans but not in gorillas, that would have important useful medical implications,” Tyler-Smith said.