Posted on Oct 12, 2016 in Education, Science & Engineering

The color blue evolved independently among tarantulas at least 8 times. iStockphoto

Biomimicry Thinking – ‘Tarantula Blue’ Now One Step Closer To Reality

Lola Gayle, STEAM Register

In December 2015, I reported on research involving blue tarantulas, which possess a striking non-iridescent shade of blue that doesn’t change when viewed at different angles. At the time, researchers from the Scripps Institution of Oceanography at UC San Diego and University of Akron (UA) set out to find out why, exactly, some tarantulas have such a vibrant hue.

“We didn’t find the answer to that question,” UA’s Bor-Kai (Bill) Hsiung told National Geographic.

The scientists did learn, however, that the spiders independently evolved the ability to make these blue colors using nanostructures in their exoskeletons, which they said could lead to new ways to improve computer or TV screens using biomimicry. This approach, also referred to as biomimetics, is used to imitate biological systems seen in nature in an effort to create sustainable solutions to real-world human challenges.

Since the spider’s blue color is not iridescent, the researchers suggested that the same process could be applied to make pigment replacements that never fade, as well as to help reduce glare on wide-angle viewing systems in phones, televisions, and other devices. I like to refer to this possible new color as “Tarantula Blue.” Catchy name, no?

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“They could be used as pigment replacements in materials such as plastics, metal, textiles and paper, and for producing color for wide-angle viewing systems in phones, televisions and other optical devices,” Mr. Hsiung said.

In April 2016, I had the immense honor of interviewing Mr. Hsiung, a biomimicry fellow in UA’s Integrated Bioscience Ph.D. program, about his work with these beautiful blue tarantulas. The research had just entered the next phase and the team had turned to crowdfunding to help make it happen.

The researchers had already designed five models of real tarantula hairs (i.e. Poecilotheria metallica and Lampropelma violaceopes) that varied in complexity. However, they wanted to dig deeper and actually fabricate those five designs using 3D nano-printing technology to test their hypotheses experimentally and determine which features produce blue and which remove iridescence.

Not long after my interview, Mr. Hsiung and his colleagues reached their funding goal and went straight to work in the lab.

Milestone In Biomimicry Research

Now, Mr. Hsiung and his colleagues at UA, Ghent University, Karlsruhe Institute of Technology, and the University of Nebraska-Lincoln are reporting on their new findings in the journal Advanced Optical Materials.

According to a statement I received from Mr. Hsiung, structural colors are more vibrant and durable than the pigments used in most human-made products. They are produced by optical effects when light interacts with nanostructures that are about the same size as the wavelength of light. One example of this is peacock tail feathers. They are pigmented brown, but their microscopic structure makes them also reflect blue, turquoise, and green light, and they are often iridescent.

The problem here is that most structural colors are strongly iridescent, changing color when viewed from different angles. Think of the Morpho butterfly — as you view its beautiful blue wings from different angles, the colors seem to sparkle and change somewhat. Pretty in nature, but not very functional when you’re watching your television and move to a new seat.

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Despite the beauty of this iridescence, it prohibits a broader usage of structural color in our daily lives because we want the colors to remain faithful, the researchers said. You could go with amorphous structures to produce non-iridescent structural colors, but they are difficult to manufacture. In contrast, they say that highly periodic designs are easy to manufacture and make vibrant structural colors, but this method still results in strong iridescence.

NOTE: Amorphous means having no definite or clear shape or form.

“In short, non-iridescent structural color is hard to come by,” Mr. Hsiung and his colleagues write. But now, they say the new research will help solve this “vexing problem.”

In the course of their research, the team found that the hairs of some species of blue tarantulas have a special flower-like shape. They had hypothesized that this shape reduced the iridescent effect resulting from periodic structures.

Now, thanks to the crowdfunding push they received earlier, the researchers were able to test this hypothesis using a series of computer simulations and physical prototypes built using cutting-edge nano-3D printing technology.

What they found was that they could almost completely wipe out any iridescence using a highly periodic structure with a flower-like shape similar to those seen in blue tarantulas. What’s more, they found that the color produced by the 3D printed structures has a viewing angle of 160 degrees. This is the largest viewing angle of any synthetic structural colors demonstrated so far, and the discovery “greatly enhances the potential application of structural color in display screens and other optical devices,” the team said in their statement.

“This is a key first step towards a future where ‘structural colorants’ replace the toxic pigments and dyes that are currently used in textile, packaging, and cosmetic industries,” Mr. Hsiung added.

A real win-win discovery for science, humanity, and the environment.

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The Future Of Tarantula Blue

When I learned of the latest results, I excitedly asked Mr. Hsiung about what the next step would be.

“This research is a ‘proof-of-concept’. Previously, no one ever thought non-iridescence can be achieved through highly order, periodic structures,” he answered. “Our research not only demonstrated it’s possible in theory (simulation), but doable (physical 3D printed prototypes). However, to be able to turn our research into real world commercialization products, we now need to consider the practicality (time & money). So, our next step is to show that these structures can be mass produced cheaply. And we already have some ideas about how to achieve that next step (i.e., we already identified potential techniques necessary for achieving that goal).”

When I asked him if I would ever be able to say that my television or t-shirt is made using ‘tarantula blue’ technology or pigments, Mr. Hsiung replied: “If one is willing to invest in the commercialization. I believe we are very likely to make ‘tarantula blue’ t-shirts in about 5 years. TV probably will take longer, but it’s definitely possible.”

I also asked him if this research may one day lead to other potential colors using the same technologies and methodology.

“The best thing about structural colors, is that we will be able to tune and achieve all colors in our human visible spectrum,” he replied. “So, the answer is YES. Infinite of colors using the same technology and methodology.”

In closing, I queried him on his favorite part about this new phase of research, from a STEM and STEAM education angle. He broke it down this way:

“So, Science: we learned how the technology works by studying natural organisms (biology). Technology and Engineering: we translate what was leaned from Science, and make it happen (realize it) through technology and engineering. Mathematics: The behavior of our prototypes can be predicted (simulated) through simple optical formula (theory). Art: the end result is beautiful and can definitely be applied to art someday.”

“Overall, making something out of nothing (especially when everyone else thinks it’s not possible) is really exciting,” Mr. Hsiung added.

In the TEDxUniversityofAkron Salon video below, Mr. Hsiung demystifies a common misperception about biomimicry. He then goes on to explain how his research contributes to the making of more durable, energy-efficient, and eco-friendly colors by incorporating Biomimicry Thinking — a methodology that integrates biomimicry into the process of any discipline.

CITATION: B.-K. Hsiung et al: “Tarantula-inspired non-iridescent photonics with long-range order.” Advanced Optical Materials 2016: DOI: 10.1002/adom.201600599.

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3D Printing • Biology • Biomimetics • Biomimicry • Biotechnology • Entomology • Evolution • Nanotechnology • Photonics • STEAM Fields • STEM Fields