Dry, arid and remote farming regions are vulnerable to water shortages, but scientists are working on a promising new solution.
As scientists have searched for solutions, an alternative water supply has been hiding in plain sight: Water vapor in the atmosphere. It is abundant, available, and endlessly renewable, just waiting for the moment that technological innovation and necessity converged to make it fit for use. Now, new super-moisture-absorbent gels developed by Yu and a team of researchers can pull that moisture from the air and bring it into soil, potentially expanding the map of farmable land around the globe to dry and remote regions that suffer from water shortages.
"This opens up opportunities to turn those previously poor-quality or inhospitable lands to become useable and without need of centralized water and power supplies," Yu said.
A renewable source of freshwater
The hydrogels are a gelatin-like substance made from synthetic materials. The gels activate in cooler, humid overnight periods and draw water from the air. During a four-week experiment, Yu's team observed that soil with these gels provided enough water to support seed germination and plant growth without an additional liquid water supply. And the soil was able to maintain the moist environment for more than a month, according to Yu.
The super absorbent gels developed at the University of Texas at Austin.
Xingyi Zhou, UT Austin
"It is promising to liberate underdeveloped and drought areas from the long-distance water and power supplies for agricultural production," Yu said.
Crops also rely on fertilizer to maintain soil fertility and increase the production yield, but it is easily lost through leaching. Runoff increases agricultural costs and contributes to environmental pollution. The interaction between the gels and agrochemicals offer slow and controlled fertilizer release to maintain the balance between the root of the plant and the soil.
The possibilities are endless
Harvesting atmospheric water is exciting on multiple fronts. The super-moisture-absorbent gel can also be used for passively cooling solar panels. Solar radiation is the magic behind the process. Overnight, as temperatures cool, the gels absorb water hanging in the atmosphere. The moisture is stored inside the gels until the thermometer rises. Heat from the sun serves as the faucet that turns the gels on so they can release the stored water and cool down the panels. Effective cooling of the solar panels is important for sustainable long-term power generation.
In addition to agricultural uses and cooling for energy devices, atmospheric water harvesting technologies could even reach people's homes.
"They could be developed to enable easy access to drinking water through individual systems for household usage," Yu said.
Next steps
Yu and the team are now focused on affordability and developing practical applications for use. The goal is to optimize the gel materials to achieve higher levels of water uptake from the atmosphere.
"We are exploring different kinds of polymers and solar absorbers while exploring low-cost raw materials for production," Yu said.
The ability to transform atmospheric water vapor into a cheap and plentiful water source would be a game-changer. One day in the not-too-distant future, if climate change intensifies and droughts worsen, this innovation may become vital to our very survival.
Silkworm silk is fragile, which limits its uses, but a few extra genes can help.
Today, biomimetics is everywhere. Shark-inspired swimming trunks, gecko-inspired adhesives, and lotus-inspired water-repellents are all taken from observing the natural world. After millions of years of evolution, nature has quite a few tricks up its sleeve. They are tricks we can learn from. And now, thanks to some spider DNA and clever genetic engineering, we have another one to add to the list.
The elusive spider silk
We’ve known for a long time that spider silk is remarkable, in ways that synthetic fibers can’t emulate. Nylon is incredibly strong (it can support a lot of force), and Kevlar is incredibly tough (it can absorb a lot of force). But neither is both strong and tough. In all artificial polymeric fibers, strength and toughness are mutually exclusive, and so we pick the material best for the job and make do.
Spider silk, a natural polymeric fiber, breaks this rule. It is somehow both strong and tough. No surprise, then, that spider silk is a source of much study.The problem, though, is that spiders are incredibly hard to cultivate — let alone farm. If you put them together, they will attack and kill each other until only one or a few survive. If you put 100 spiders in an enclosed space, they will go about an aggressive, arachnocidal Hunger Games. You need to give each its own space and boundaries, and a spider hotel is hard and costly. Silkworms, on the other hand, are peaceful and productive. They’ll hang around all day to make the silk that has been used in textiles for centuries. But silkworm silk is fragile. It has very limited use.
The elusive – and lucrative – trick, then, would be to genetically engineer a silkworm to produce spider-quality silk. So far, efforts have been fruitless. That is, until now.
We can have silkworms creating silk six times as tough as Kevlar and ten times as strong as nylon.
Spider-silkworms
Junpeng Mi and his colleagues working at Donghua University, China, used CRISPR gene-editing technology to recode the silk-creating properties of a silkworm. First, they took genes from Araneus ventricosus, an East Asian orb-weaving spider known for its strong silk. Then they placed these complex genes – genes that involve more than 100 amino acids – into silkworm egg cells. (This description fails to capture how time-consuming, technical, and laborious this was; it’s a procedure that requires hundreds of thousands of microinjections.)
This had all been done before, and this had failed before. Where Mi and his team succeeded was using a concept called “localization.” Localization involves narrowing in on a very specific location in a genome. For this experiment, the team from Donghua University developed a “minimal basic structure model” of silkworm silk, which guided the genetic modifications. They wanted to make sure they had the exactly right transgenic spider silk proteins. Mi said that combining localization with this basic structure model “represents a significant departure from previous research.” And, judging only from the results, he might be right. Their “fibers exhibited impressive tensile strength (1,299 MPa) and toughness (319 MJ/m3), surpassing Kevlar’s toughness 6-fold.”
A world of super-materials
Mi’s research represents the bursting of a barrier. It opens up hugely important avenues for future biomimetic materials. As Mi puts it, “This groundbreaking achievement effectively resolves the scientific, technical, and engineering challenges that have hindered the commercialization of spider silk, positioning it as a viable alternative to commercially synthesized fibers like nylon and contributing to the advancement of ecological civilization.”
Around 60 percent of our clothing is made from synthetic fibers like nylon, polyester, and acrylic. These plastics are useful, but often bad for the environment. They shed into our waterways and sometimes damage wildlife. The production of these fibers is a source of greenhouse gas emissions. Now, we have a “sustainable, eco-friendly high-strength and ultra-tough alternative.” We can have silkworms creating silk six times as tough as Kevlar and ten times as strong as nylon.
We shouldn’t get carried away. This isn’t going to transform the textiles industry overnight. Gene-edited silkworms are still only going to produce a comparatively small amount of silk – even if farmed in the millions. But, as Mi himself concedes, this is only the beginning. If Mi’s localization and structure-model techniques are as remarkable as they seem, then this opens up the door to a great many supermaterials.
Nature continues to inspire. We had the bird, the gecko, and the shark. Now we have the spider-silkworm. What new secrets will we unravel in the future? And in what exciting ways will it change the world?
This article originally appeared on Freethink, home of the brightest minds and biggest ideas of all time.
