When people think of greenhouse gas emissions from transportation, what often comes to mind are airplanes and land vehicles like cars or trucks. But as efforts to slow climate change are ramping up, the spotlight is on another form of transport: ships. 

The U.N.’s International Maritime Organization (IMO) has set targets to reduce shipping greenhouse gas emissions by at least 40% by 2030 and 70% by 2040, aiming for net-zero by 2050. Shipping currently accounts for about 3% of global annual greenhouse gas emissions, and the pressure is on shipping companies to meet these ambitious goals.

Across Georgia Tech, researchers are working toward a sustainable future for ocean shipping. This includes Valerie Thomas, the Anderson-Interface Chair of Natural Systems Professor in the H. Milton Stewart School of Industrial and Systems Engineering, and in the School of Public Policy. She is scholar of energy systems, sustainability, assessment, and low-carbon transportation fuels, and her work touches many aspects of the maritime industry. 

Finding Sustainable Solutions

“Today, we ship a lot of goods by ocean freight, and there is certainly an environmental impact with shipping,” Thomas said.  “But the emissions from shipping a product from East Asia to the U.S. on a bulk carrier vessel are significantly lower than trucking a product across the U.S. When ships are filled to the brim with cargo and are moving slowly across oceans, this is energy efficient, fuel efficient, and even cost efficient per ton of ‘stuff’ transported.” 

While ocean shipping is significantly more energy efficient than air or land transport and contributes far fewer emissions, Thomas says cutting down on ocean freight emissions will require a great deal more effort. One way is to find more eco-friendly fuels. 

“I look at big systems, and one of those areas is investigating alternative fuels,” Thomas said. “I’m often trying to figure out how much greenhouse gas various fuels emit, what other types of emissions or matter are coming out, and how to compare different fuel options.”

Thomas is a leading expert in life-cycle assessment. It is a method used to evaluate a fuel or technology's environmental impact throughout its entire cycle — from raw materials extraction, processing, manufacturing, distribution, and ultimately, use. Right now, basically all ships use petroleum fuels, which emit carbon dioxide and particulate matter into the air. 

Finding fuel alternatives is not a simple task: Just because a fuel might initially seem like a promising low-carbon option, that is not always the case in the end. Thomas’s expertise in life-cycle assessments helps her figure out whether these possible fuels are truly environmentally friendly.

“One such example is hydrogen: It doesn’t emit carbon dioxide when burned,” Thomas said. “But the manufacturing of hydrogen can emit carbon dioxide, and therefore, hydrogen is not always a low-carbon fuel on a lifecycle basis.”

Helping the Shipping Industry Cut Carbon 

Patricia Stathatou, a researcher at Georgia Tech’s Renewable Bioproducts Institute, specializes in sustainability assessment of chemical engineering processes and products, which includes lifecycle assessments and techno-economic assessments, evaluating both the environmental impacts and the economic viability of products and processes. Stathatou, who will join the School of Chemical and Biomolecular Engineering as an assistant professor in January 2025, also conducts experiments to support these assessments and guide the development of new technologies. 

“My contribution to the lifecycle assessment field is that I support assessments with in-field emission monitoring, taking samples, and performing chemical analyses,” Stathatou said. “This helps identify specific pollutants that might be emitted into the air or be present in water, wastewater, or solid waste streams.”

But as maritime shipping companies rise to the challenge of cutting emissions, they often do not know where to start. This is where Stathatou’s experience comes in. 

During her postdoctoral research at MIT, a major shipping company reached out to Stathatou and her colleagues asking for help in cutting emissions. They wanted to increase the energy efficiency of their fleet and investigate different strategies and technologies to eventually reach the IMO’s emissions goals.

Because of Stathatou’s expertise in alternative fuels, biofuels, and sustainable energy sources, she investigated potential solutions for the company, which included a six-day research trip monitoring emissions aboard one of the company’s bulk carrier vessels in East Asia. Her work involves designing experiments, measuring emissions, and evaluating the environmental impact of different fuels onboard bulk carrier vessels. 

“Ten years ago, there weren't rigorous goals or guidelines for reducing emissions in the shipping industry — and not much scientific collaboration in the process,” Stathatou said. “If we are to make a difference in the industry in regard to climate, we need partnerships with shipping companies to help guide their efforts.”

Stathatou plans to continue her collaborations with shipping companies and expects to carry out more on-ship evaluations soon. 

The Big Picture 

According to Thomas, a holistic approach is needed to make shipping more sustainable. "It's not just about the fuels we use; it's about optimizing supply chains, reducing empty freight, and leveraging multimodal transportation options," Thomas said. "By embracing net-zero freight initiatives and maximizing efficiency in logistics, we can achieve meaningful reductions in emissions while meeting the demands of global trade."

Encouraging shifts to ocean freight is another means of reducing emissions. For example, if a company wants to transport goods from Miami to Baltimore, they don’t need to go by road or rail. “You can ship your freight on the ocean along the coast, and that could be more environmentally efficient,” Thomas said. 

The work Thomas and Stathatou do is part of a broad portfolio of shipping sustainability research at Georgia Tech, which also includes the Georgia Tech Supply Chain and Logistics Institute, the Panama Logistics and Innovation Research Center, and the Net Zero Freight Systems Program, which Thomas co-leads. These partnerships aim to enhance the efficiency and sustainability of global supply chains, leveraging innovative research and practical applications.

“The work of evaluating different fuels, technologies, and strategies is not trivial, and figuring out these new methods does not happen quickly,” Thomas said. “These are difficult technologies, and it takes a long time to put them in place. That is why we need to do this work now.” 

Stathatou envisions that, with more shipping companies now looking to curb their emissions, there will be significant adoption of new fuels and technologies within the next decade.

“Ocean shipping is a transportation sector that we cannot go without, and so decarbonizing it is very important,” Stathatou said. “I believe the ability to perform these assessments and guide the development of future solutions will have a tremendous impact on humanity.”

Knitting, the age-old craft of looping and stitching natural fibers into fabrics, has received renewed attention for its potential applications in advanced manufacturing. Far beyond their use for garments, knitted textiles are ideal for designing and fabricating emerging technologies like wearable electronics or soft robotics — structures that need to move and bend. 

Knitting transforms one-dimensional yarn into two-dimensional fabrics that are flexible, durable, and highly customizable in shape and elasticity. But to create smart textile design techniques that engineers can use, understanding the mechanics behind knitted materials is crucial. 

Physicists from the Georgia Institute of Technology have taken the technical know-how of knitting and added mathematical backing to it. In a study led by Elisabetta Matsumoto, associate professor in the School of Physics, and Krishma Singal, a graduate researcher in Matsumoto’s lab, the team used experiments and simulations to quantify and predict how knit fabric response can be programmed. By establishing a mathematical theory of knitted materials, the researchers hope that knitting — and textiles in general — can be incorporated into more engineering applications.

Their research paper, “Programming Mechanics in Knitted Materials, Stitch by Stitch,” was published in the journal Nature Communications. 

“For centuries, hand knitters have used different types of stitches and stitch combinations to specify the geometry and ‘stretchiness’ of garments, and much of the technical knowledge surrounding knitting has been handed down by word of mouth,” said Matsumoto.

But while knitting has often been dismissed as unskilled, poorly paid “women’s work,” the properties of knits can be more complex than traditional engineering materials like rubbers or metals. 

For this project, the team wanted to decode the underlying principles that direct the elastic behavior of knitted fabrics. These principles are governed by the nuanced interplay of stitch patterns, geometry, and yarn topology — the undercrossings or overcrossings in a knot or stitch. "A lot of yarn isn’t very stretchy, yet once knit into a fabric, the fabric exhibits emergent elastic behavior," Singal said. 

“Experienced knitters can identify which fabrics are stretchier than others and have an intuition for its best application,” she added. “But by understanding how these fabrics can be programmed and how they behave, we can expand knitting’s application into a variety of fields beyond clothing.”

Through a combination of experiments and simulations, Matsumoto and Singal explored the relationships among yarn manipulation, stitch patterns, and fabric elasticity, and how these factors work together to affect bulk fabric behavior. They began with physical yarn and fabric stretching experiments to identify main parameters, such as how bendable or fluffy the yarn is, and the length and radius of yarn in a given stitch. 

They then used the experiment results to design simulations to examine the yarn inside a stitch, similar to an X-ray. It is difficult to see inside stitches during the physical measurements, so the simulations are used to see what parts of the yarn have interacted with other parts. The simulations are used to recreate the physical measurements as accurately as possible.

Through these experiments and simulations, Singal and Matsumoto showed the profound impact that design variations can have on fabric response and uncovered the remarkable programmability of knitting. "We discovered that by using simple adjustments in how you design a fabric pattern, you can change how stretchy or stiff the bulk fabric is," Singal said. "How the yarn is manipulated, what stitches are formed, and how the stitches are patterned completely alter the response of the final fabric."

Matsumoto envisions that the insights gleaned from their research will enable knitted textile design to become more commonly used in manufacturing and product design. Their discovery that simple stitch patterning can alter a fabric’s elasticity points to knitting’s potential for cutting-edge interactive technologies like soft robotics, wearables, and haptics.

“We think of knitting as an additive manufacturing technique — like 3D printing, and you can change the material properties just by picking the right stitch pattern,” Singal said.

Matsumoto and Singal plan to push the boundaries of knitted fabric science even further, as there are still numerous questions about knitted fabrics to be answered. 

"Textiles are ubiquitous and we use them everywhere in our lives," Matsumoto said. "Right now, the hard part is that designing them for specific properties relies on having a lot of experience and technical intuition. We hope our research helps make textiles a versatile tool for engineers and scientists too."

 

Note: Sarah Gonzalez (Georgia Tech) and Michael Dimitriyev (Texas A&M) are also co-first authors of the study. 

Citation: Singal, K., Dimitriyev, M.S., Gonzalez, S.E. et al. Programming mechanics in knitted materials, stitch by stitch. Nat Commun 15, 2622 (2024). 

DOI: https://doi.org/10.1038/s41467-024-46498-z

Funding: Research Corporation for Science Advancement, National Science Foundation, and the Alfred P. Sloan Foundation 

A new in-depth analysis shows that users who reply to misinformation about the Covid-19 vaccine on X, formerly known as Twitter, with a positive attitude, politeness, and strong evidence are more likely to encourage others to disbelieve the incorrect information.

Researchers from three Georgia Tech schools found the most effective way to confront vaccine misinformation on the X platform. 

They also created a predictive tool to show users whether their reply will succeed in changing minds or backfire and reinforce the misinformation. It can also pinpoint well-meaning replies meant to contradict misinformation but that interfere with social correction. 

A research paper with the full findings will be presented this week at the ACM Web Science Conference in Stuttgart, Germany.

Like white blood cells attacking a virus, social media users have been known to band together and debunk online misinformation being spread online in a phenomenon researchers call social correction. 

The success rate of social correction on most social media sites has not been determined. However, researchers now have a clearer picture of how successful user input can be on X. 

Their method uses a blend of artificial intelligence with a dataset of 1.5 million tweets containing misinformation about the Covid-19 vaccine. The researchers then studied user replies to misinformation as well as the consequences of those replies. 

In the paper, the researchers write that their data set pre-dates the rollout of X’s community notes feature, which allows users to submit corrections to posts on the platform. They point out that this system restricts users from responding to fact-checking text and labels and does not reflect the large flow of information on the site. 

As one of the first taxonomies of user social correction on the X platform, the researchers hope will aid future fact-checking efforts. While the paper only focused on text posts in the English language, it is a framework that can be expanded to address the growing threat of misinformation online. 

Corrective or Backfire: Characterizing and Predicting User Response to Social Correction was co-authored by Ph.D. students Bing He and Yingchen (Eric) Ma and their advisors Regents’ Entrepreneur Mustaque Ahamad, a professor with joint appointments in the School of Cybersecurity and Privacy and the School of Computer Science, and School of Computational Science and Engineering Assistant Professor Srijan Kumar. 

An electrochemical process developed at Georgia Tech could offer new protection against bacterial infections without contributing to growing antibiotic resistance.

The approach capitalizes on the natural antibacterial properties of copper and creates incredibly small needle-like structures on the surface of stainless steel to kill harmful bacteria like E. coli and Staphylococcus. It’s convenient and inexpensive, and it could reduce the need for chemicals and antibiotics in hospitals, kitchens, and other settings where surface contamination can lead to serious illness.

It also could save lives: A global study of drug-resistant infections found they directly killed 1.27 million people in 2019 and contributed to nearly 5 million other deaths — making these infections one of the leading causes of death for every age group.

Researchers described the copper-stainless steel and its effectiveness May 20 in the journal Small.

Read the full story on the College of Engineering website.

Parth Arora is the founder of Third Dimension Fitness, a platform for gamified cardio through mixed reality, which was recently acquired by Elbo, an education-focused company based in Singapore. He began his company as a project in the summer of 2022. Since then, it has gained thousands of users and made thousands in revenue each month. Arora is a senior in computer science. He participated in the Spring 2024 Startup Launch, the first cohort to be held outside of the summer program. Below is a Q&A with Arora. 

Did you always want to be an entrepreneur?

I always did. I had my first company, an educational technology app, when I was 16, which ran for about two years. I ended it in my first year of college. I'm from India originally and the vision was to provide resources to the larger mass market of India for extracurricular activities. But, we realized there wasn't a business model. When we tried to make money, we started serving the rich kids. When we tried to serve the market, we didn't make money, which doesn't make investors happy, though we did end up making enough money to repay them.

That didn't stop me; it just gave me more lessons. 

What other experience in entrepreneurship have you had?

I've been involved in entrepreneurship communities at Georgia Tech forever. I was co-director of Startup Exchange, which is where I met a lot of really driven people. I got a chance to build their fellowship program and initiate their first pitch competition, which is now called Summit. I've collaborated with CREATE-X for different events, and I try to attend any event hosted by CREATE-X, Startup Exchange, or ATDC.

Why did you choose to join the spring cohort of Startup Launch this year?

CREATE-X provides everything you need, like legal support, financial support, sales support, mentors, and an introduction to VCs, which is why I decided to join the Launch program. I think all of that boosted our startup’s growth.

Why did you feel like acquisition was the way to go for your company?

I think because I always knew this wasn’t “the” thing I was going to do. This summer I'll be starting to work for Apple on their VisionPro team, and it has a direct conflict-of-interest. They wanted me to stop working on this for a while. So, I felt like this might be a good time to explore the acquisition.  We had really rich content, which had proven to work. We had curated that content after hundreds of customer interviews, and we had advisors from Nike, Disney, and Netflix. I knew that was a strong point, so that's why I knew that acquisition would be a good exit. 

What support have you had in taking the acquisition path?

Seth [Radman, who has had multiple exits himself and is a Startup Launch alumnus] has been guiding me professionally for a while. I met him at previous events through Startup Exchange, but then he recently came to a CREATE-X event. Rahul [Saxena, CREATE-X director], has also been a great support for me since day one. He was the one who suggested Startup Launch to me.

In December of last year, we started monetizing. We were testing different things. It was helpful to share the numbers and the data points with Rahul, mentors, and other people in my cohort so that I was not blindsided, and I could take actions based on the educated analysis of a database. It helped me drive down our customer acquisition cost, increase our customer lifetime value, and didn't keep me in my own bubble.

How were you okay with letting that product go?

It was a tough decision; it was my baby. I'd been working on it 10 to 15 hours a day, at least for the last few months. Rahul and Seth convinced me that if this is not the thing you want to do long-term and you know the market isn't big enough, you should move on to the next thing and put your time and energy there. 

I had to use my brain, and not my heart.

What's the biggest piece of advice that you've received as you developed your company?

Try to never lie to yourself, which is harder than it seems. I've built two companies and worked with several others, and I still lie to myself. When you love your product so much, it's very easy to lie to yourself about how there is a market for it, or people are using it. I think even in the future, I’ll probably be caught doing that, but the best way I've found to overcome that is to surround yourself with people who can tell you when you are doing it and help you see your company the way it is instead of the way you want it to be.

How has this decision affected you so far?

My lifestyle has completely changed, from looking at a dashboard every 10 to 15 minutes, seeing how the product is doing, and burning so many fires every 30 minutes, to being pretty chill. Like, what am I supposed to think about before I go to bed? What am I supposed to do now? Who are the customers I am supposed to be thinking about? It's been interesting, but I think this gives me space to now work on that next venture and have more time to think about what I want to do next.

Do you think you'll want to return to entrepreneurship in the future?

Yes, for sure. All the money I received from the acquisition will also fuel my next venture. My main goal is to grow in this industry. I'm an entrepreneur at heart, so I will be returning to the space soon or building products that people like. 

How are you celebrating this win?

I did celebrate it on our last day with Rahul, my amazing mentor, Margaret [Weniger, who founded Rising Tide], and the other cohort members. I will be celebrating it with a few of my friends because my 21st birthday is coming around, so I'll be celebrating these occasions together. 

But I don't want to take the money out from the company or for anything else, because it’s for my next venture. It shouldn't change my lifestyle at all, so I've kept all that money in a separate place.

What encouragement would you give to students interested in pursuing a startup?

Relative to other colleges, we have a cushion, a sense of security that we will get good jobs. Entrepreneurship is a riskier and more unpredictable path, which I've seen, and I'm personally experiencing right now having to choose between Big Tech versus entrepreneurship. But once you start building it and when you hear from your first customer how you affected the way they live, then there's no going back. Statistically, you'll probably fail, but you won't know until you start building; and if you do fail, it’ll teach you so many valuable lessons that are applicable in whatever career path you choose.

CREATE-X will launch its 12th cohort of Startup Launch on Aug. 29 at 5 p.m. in the Georgia Tech Exhibition Hall. Register today to secure your spot.

Interested in becoming a CREATE-X supporter? Startup Launch is made possible by contributions to Transforming Tomorrow, a $2 billion comprehensive campaign designed to secure resources that will advance the Institute and its impact, and by the continued engagement of our entrepreneurial ecosystem. Learn more about philanthropy at Georgia Tech and donate by visiting transformingtomorrow.gatech.edu.

To become a mentor in CREATE-X, visit the CREATE-X mentorship page. Any other inquiry may be sent to create-x@groups.gatech.edu. We appreciate your help and commitment to supporting our students in research and innovation.

Georgia’s saltwater marshes — living where the land meets the ocean — stretch along the state’s entire 100-mile coastline. These rich ecosystems are largely dominated by just one plant: grass.

Known as cordgrass, the plant is an ecosystem engineer, providing habitats for wildlife, naturally cleaning water as it moves from inland to the sea, and holding the shoreline together so it doesn’t collapse. Cordgrass even protects human communities from tidal surges.

Understanding how these plants stay healthy is of crucial ecological importance. For example, one known plant stressor prevalent in marsh soils is the dissolved sulfur compound, sulfide, which is produced and consumed by bacteria. But while the Georgia coastline boasts a rich tradition of ecological research, understanding the nuanced ways bacteria interact with plants in these ecosystems has been elusive. Thanks to recent advances in genomic technology, Georgia Tech biologists have begun to reveal never-before-seen ecological processes.

The team’s work was published in Nature Communications. 

Joel Kostka, the Tom and Marie Patton Distinguished Professor and associate chair for Research in the School of Biological Sciences, and Jose Luis Rolando, a postdoctoral fellow, set out to investigate the relationship between the cordgrass Spartina alterniflora and the microbial communities that inhabit their roots, identifying the bacteria and their roles.

“Just like humans have gut microbes that keep us healthy, plants depend on microbes in their tissues for health, immunity, metabolism, and nutrient uptake,” Kostka said. “While we’ve known about the reactions that drive nutrient and carbon cycling in the marsh for a long time, there’s not as much data on the role of microbes in ecosystem functioning.”

Out in the Marsh

A major way that plants get their nutrients is through nitrogen fixation, a process in which bacteria convert nitrogen into a form that plants can use. In marshes, this role has mostly been attributed to heterotrophs, or bacteria that grow and get their energy from organic carbon. Bacteria that consume the plant toxin sulfide are chemoautotrophs, using energy from sulfide oxidation to fuel the uptake of carbon dioxide to make their own organic carbon for growth.

“Through previous work, we knew that Spartina alterniflora has sulfur bacteria in its roots and that there are two types: sulfur-oxidizing bacteria, which use sulfide as an energy source, and sulfate reducers, which respire sulfate and produce sulfide, a known toxin for plants,” Rolando said. “We wanted to know more about the role these different sulfur bacteria play in the nitrogen cycle.”

Kostka and Rolando headed to Sapelo Island, Georgia, where they have regularly conducted fieldwork in the salt marshes. Wading into the marsh, shovels and buckets in hand, the researchers and their students collected cordgrass along with the muddy sediment samples that cling to their roots. Back at the field lab, the team gathered around a basin filled with creek water and carefully washed the grass, gently separating the plant roots.

Next, they used a special technique involving heavier versions of chemical elements that occur in nature as tracers to track the microbial processes. They also analyzed the DNA and RNA of the microbes living in different compartments of the plants.

Using a sequencing technology known as shotgun metagenomics, they were able to retrieve the DNA from the whole microbial community and reconstruct genomes from newly discovered organisms. Similarly, untargeted RNA sequencing of the microbial community allowed them to assess which microbial species and specific functions were active in close association with plant roots.

Using this combination of techniques, they found that chemoautotrophic sulfur-oxidizing bacteria were also involved in nitrogen fixation. Not only did these bacteria help plants by detoxifying the root zone, but they also played a crucial role in providing nitrogen to the plants. This dual role of the bacteria in sulfur cycling and nitrogen fixation highlights their importance in coastal ecosystems and their contribution to plant health and growth.

"Plants growing in areas with high levels of sulfide accumulation tend to be smaller and less healthy," said Rolando. "However, we found that the microbial communities within Spartina roots help to detoxify the sulfide, enhancing plant health and resilience."

Local to Global Significance

Cordgrasses aren’t just the main player in Georgia marshes; they also dominate marsh landscapes across the entire Southeast, including the Carolinas and the Gulf Coast. Moreover, the researchers found that the same bacteria are associated with cordgrass, mangrove, and seagrass roots in coastal ecosystems across the planet.

"Much of the shoreline in tropical and temperate climates is covered by coastal wetlands,” Rolando said. “These areas likely harbor similar microbial symbioses, which means that these interactions impact ecosystem functioning on a global scale."  

Looking ahead, the researchers plan to further explore the details of how marsh plants and microbes exchange nitrogen and carbon, using state-of-the-art microscopy techniques coupled with ultra-high-resolution mass spectrometry to confirm their findings at the single-cell level.

"Science follows technology, and we were excited to use the latest genomic methods to see which types of bacteria were there and active,” Kostka said. “There's still much to learn about the intricate relationships between plants and microbes in coastal ecosystems, and we are beginning to uncover the extent of the microbial complexity that keeps marshes healthy.”

 

Citation: Rolando, J.L., Kolton, M., Song, T. et al. Sulfur oxidation and reduction are coupled to nitrogen fixation in the roots of the salt marsh foundation plant Spartina alterniflora. Nat Commun 15, 3607 (2024).

DOI: https://doi.org/10.1038/s41467-024-47646-1

Funding: This work was supported in part by an institutional grant (NA18OAR4170084) to the Georgia Sea Grant College Program from the National Sea Grant Office, National Oceanic and Atmospheric Administration, US Department of Commerce, and by a grant from the National Science Foundation (DEB 1754756).

When looking for an environmentally friendly and cost-effective way to clean up contaminated water and soil, Georgia Tech researchers Patricia Stathatou and Christos Athanasiou turned to yeast. A cheap byproduct from fermentation processes — e.g., something your local brewery discards in mass quantities after making a batch of beer — yeast is widely known as an effective biosorbent. Biosorption is a mass transfer process by which an ion or molecule binds to inactive biological materials through physicochemical interactions.

When they initially studied this process, Stathatou and Athanasiou found that yeast can effectively and rapidly remove trace lead — at challenging initial concentrations below one part per million — from drinking water. Conventional water treatment methods either fail to eliminate lead at these low levels or result in high financial and environmental costs to do so. In a paper published today in RSC Sustainability, the researchers show how this process can be scaled.

“If you put yeast directly into water to clean it, you will need an additional treatment step to remove the yeast from the water afterward,” said Stathatou, a research scientist at the Renewable Bioproducts Institute and an incoming assistant professor at the School of Chemical and Biomolecular Engineering. “To implement this process at scale without requiring additional separation steps, the yeast cells need a housing.”

“Additionally, because yeast is abundant— in some cases, brewers even pay companies to haul it away as a waste byproduct — this process gives the yeast a second life,” said Athanasiou, an assistant professor in the Daniel Guggenheim School of Aerospace Engineering. “It’s a plentiful low, or even negative, value resource, making this purification process inexpensive and scalable.”

To develop a housing for the yeast, Stathatou and Athanasiou partnered with MIT chemical engineers Devashish Gokhale and Patrick S. Doyle. Gokhale and Stathatou are the lead authors of this new study that demonstrates the yeast water purification process’s scalability.

“We decided to make these hollow capsules— analogous to a multivitamin pill — but instead of filling them up with vitamins, we fill them up with yeast cells,” Gokhale said. “These capsules are porous, so the water can go into the capsules and the yeast are able to bind all of that lead, but the yeast themselves can’t escape into the water.”

The yeast-laden capsules are sufficiently large, about half a millimeter in diameter, for easy separation from water by gravity. This means they can be used to make packed-bed bioreactors or biofilters, with contaminated water flowing through these hydrogel-encased yeast cells and coming out clean.

Stathatou and Athanasiou envision using these hydrogel yeast capsules in small biofilters consumers can put on their kitchen faucets, or biofilters large enough to fit municipal or industrial wastewater treatment systems. But to enable such scalability, the yeast-laden capsules’ ability to withstand the force generated by water flowing inside such systems needed to be studied as well.

To determine this, Athanasiou tested the capsules’ mechanical robustness, which is how strong and sturdy they are in the presence of waterflow forces. He found they can withstand forces like those generated by water running from a faucet, or even flows like those in water treatment plants that serve a few hundred homes. “In previous attempts to scale up biosorption with similar approaches, lack of mechanical robustness has been a common cause of failure,” Athanasiou said. “We wanted to make sure our work addressed this issue from the very beginning to ensure scalability.”

“After assessing the mechanical robustness of the yeast-laden capsules, we made a prototype biofilter using a 10-ml syringe,” Stathatou explained. “The initial lead concentration of water entering the biofilter was 100 parts per billion; we demonstrated that the biofilter could treat the contaminated water, meeting EPA drinking water guidelines, while operating continuously for 12 days.”

The researchers hope to identify ways to isolate and collect specific contaminants left behind in the filtering yeast, so those too can be used for other purposes.

“Apart from lead, which is widely used in systems for energy generation and storage, this process could be used to remove and recover other metals and rare earth elements as well,” Athanasiou said. “This process could even be useful in space mining or other space applications.”

They also would like to find a way to keep reusing the yeast. “But even if we can’t reuse yeast indefinitely, it is biodegradable,” Stathatou noted. “It doesn’t need to be put into an industrial composter or sent to a landfill. It can be left on the ground, and the yeast will naturally decompose over time, contributing to nutrient cycling.”

This circular approach aims to reduce waste and environmental impact, while also creating economic opportunities in local communities. Despite numerous lead contamination incidents across the U.S., the team’s successful biosorption method notably could benefit low-income areas historically burdened by pollution and limited access to clean water, offering a cost-effective remediation solution. “We think there’s an interesting environmental justice aspect to this, especially when you start with something as low-cost and sustainable as yeast, which is essentially available anywhere,” Gokhale says.

Moving forward, Stathatou and Athanasiou are exploring other uses for their hydrogel-yeast purification method. The researchers are optimistic that, with modifications, this process can be used to remove additional inorganic and organic contaminants of emerging concern, such as PFAS — or “forever” chemicals — from the water or the ground.

Citation: Devashish Gokhale, Patritsia M. Stathatou, Christos E. Athanasiou, and Patrick S. Doyle, “Yeast-laden Hydrogel Capsules for Scalable Trace Lead Removal from Water,” RSC Sustainability. DOI:

Funding: Patricia Stathatou was supported by funding from the Renewable Bioproducts Institute at Georgia Tech. Devashish Gokhale was supported by the Rasikbhai L. Meswani Fellowship for Water Solutions and the MIT Abdul Latif Jameel Water and Food Systems Lab (J-WAFS).

 

The call from his mom is still vivid 20 years later. Moments this big and this devastating can define lives, and for Hong Yeo, today a Georgia Tech mechanical engineer, this call certainly did. Yeo was a 21-year-old in college studying car design when his mom called to tell him his father had died in his sleep. A heart attack claimed the life of the 49-year-old high school English teacher who had no history of heart trouble and no signs of his growing health threat. For the family, it was a crushing blow that altered each of their paths. 

“It was an uncertain time for all of us,” said Yeo. “This loss changed my focus.” 

For Yeo, thoughts and dreams of designing cars for Hyundai in Korea turned instead toward medicine. The shock of his father going from no signs of illness to gone forever developed into a quest for medical answers that might keep other families from experiencing the pain and loss his family did — or at least making it less likely to happen.  

Yeo’s own research and schooling in college pointed out a big problem when it comes to issues with sleep and how our bodies’ systems perform — data. He became determined to invent a way to give medical doctors better information that would allow them to spot a problem like his father’s before it became life-threatening. 

His answer: a type of wearable sleep data system. Now very close to being commercially available, Yeo’s device comes after years of working on the materials and electronics for an easy-to-wear, comfortable mask that can gather data about sleep over multiple days or even weeks, allowing doctors to catch sporadic heart problems or other issues. Different from some of the bulky devices with straps and cords currently available for at-home heart monitoring, it offers the bonuses of ease of use and comfort, ensuring little to no alteration to users’ bedtime routine or wear. This means researchers can collect data from sleep patterns that are as close to normal sleep as possible.  

“Most of the time now, gathering sleep data means the patient must come to a lab or hospital for sleep monitoring. Of course, it’s less comfortable than home, and the devices patients must wear make it even less so. Also, the process is expensive, so it’s rare to get multiple nights of data,” says Audrey Duarte, University of Texas human memory researcher.  

Duarte has been working with Yeo on this system for more than 10 years. She says there are so many mental and physical health outcomes tied to sleep that good, long-term data has the potential to have tremendous impact. 

“The results we’ve seen are incredibly encouraging, related to many things —from heart issues to areas I study more closely like memory and Alzheimer’s,” said Duarte. 

Yeo’s device may not have caught the arrhythmia that caused his father’s heart attack, but nights or weeks of data would have made effective medical intervention much more likely.  

Inspired by his own family’s loss, Yeo’s life’s work has become a tool of hope for others.  

Biomedical engineer Annabelle Singer has spent the past decade developing a noninvasive therapy for Alzheimer’s disease that uses flickering lights and rhythmic tones to modulate brain waves. Now she has discovered that the technique, known as flicker, also could benefit patients with a host of other neurological disorders, from epilepsy to multiple sclerosis.

Previously, Singer and her collaborators demonstrated that the lights and sounds, delivered to patients through goggles and headphones, have beneficial effects. Flicker has been successful in animal studies and in early human feasibility trials, where it was tested for safety, tolerance, and patient adherence.

Now, thanks to a clinical trial for people with epilepsy, the researchers quantified flicker’s effects with unprecedented precision. They also made an unexpected, but encouraging, discovery: The treatment reduced interictal epileptiform discharges (IEDs) in the brain.

These large, intermittent electrophysiological events are observed between seizures in people with epilepsy. They appear as sharp spikes on an EEG readout.

“What’s interesting about these IEDs is that they don’t just occur in epilepsy,” said Singer, McCamish Foundation Early Career Professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. “They occur in autism, multiple sclerosis, Alzheimer’s, and other neurological disorders, too.” And IEDs disrupt normal brain function, causing memory impairment.

Singer and her team published their findings recently in Nature Communications.

The Rhythm in Our Heads

Inside the brain are elaborate symphonies of electrical activity: brain waves, or oscillations, that compose our memories, thoughts, and emotions. Singer wants to modulate those oscillations for therapeutic purposes. 

At specific frequencies of light and sound, the flicker treatment can induce gamma oscillations in mice. This helps the brain recruit microglia, cells responsible for removing beta amyloid, which is believed to play a central role in Alzheimer’s pathology. Part of the work is in recording what’s happening in the brain during treatment to verify how it’s working.

The patients in the trial were under the care of physician Jon Willie at the Emory University Hospital Epilepsy Monitoring Unit. (Willie, co-corresponding author of the study with Singer, is now at Washington University in St. Louis.) They were awaiting surgery to remove an area of the brain where seizures occur. Before that could happen, they had to undergo intracranial seizure monitoring — recording electrodes are placed in the brain to pinpoint the seizure onset zone and determine exactly which tissue should be removed. Then, patients and their care team wait for a seizure to happen. It can take days.

“In human studies, we’ve used noninvasive methods like functional MRI or scalp EEG, but they have real downsides in terms of resolution,” Singer said. “Working with these patients was a game changer. These are people with treatment-resistant epilepsy, which means that drugs aren’t working for them.”

Pathway to Healing

Singer’s team recruited 19 patients. Lead author of the study, Lou Blanpain, a former Ph.D. student in Singer’s lab and now a medical student at Emory, went from patient to patient with the flicker stimulation and recording equipment.

“Because these patients already had recording probes implanted for clinical reasons, we were able to record directly from the brain,” Singer said. “We’ve never been able to get recordings of this quality during flicker treatment before.”

As the researchers expected, flicker modulated the visual and auditory brain regions that respond strongly to stimuli. But it also reached deeper, into the medial temporal lobe and prefrontal cortex, brain regions crucial for memory. And across the brain, in regions Singer hadn’t fully explored before, she found IEDs were decreasing. 

“That has important implications for whether flicker is therapeutically relevant for people with Alzheimer’s, but also in general if we want to target anything beyond the primary sensory regions,” she said. “All of this points to the potential use of flicker in a lot of different contexts. Going forward, we’re definitely going to look at other conditions and other potential implications.”

 

Citation: Lou T. Blanpain, Eric R. Cole, Emily Chen, James K. Park, Michael Y. Walelign, Robert E. Gross, Brian T. Cabaniss, Jon T. Willie, Annabelle C. Singer. “Multisensory Flicker Modulates Widespread Brain Networks and Reduces Interictal Epileptiform Discharges,” Nature Communications. 

Funding: National Institutes of Health (R01 NS109226, RF1NS109226, RF1AG078736, R01 MH120194, P41 EB018783, MH12019), DARPA, McCamish Foundation, Packard Foundation.

Competing interests: Annabelle Singer owns shares in Cognito Therapeutics, which aims to develop gamma stimulation-related products. These conflicts are managed by Georgia Tech’s Office of Research Integrity Assurance.