Tag Archives: Northwestern University

Concrete collapse and research into durability

I have two items about concrete buildings, one concerns the June 24, 2021 collapse of a 12-storey condominium building in Surfside, close to Miami Beach in Florida. There are at least 20 people dead and, I believe, over 120 are still unaccounted for (July 2, 2021 Associated Press news item on Canadian Broadcasting Corporation news online website).

Miami collapse

Nate Berg’s June 25, 2021 article for Fast Company provides an instructive overview of the building collapse (Note: A link has been removed),

Why the building collapsed is not yet known [emphasis mine]. David Darwin is a professor of civil engineering at the University of Kansas and an expert in reinforced concrete structures, and he says the eventual investigation of the Surfside collapse will explore all the potential causes, ranging from movement in the foundation before the collapse, corrosion in the debris, and excessive cracking in the part of the building that remains standing. “There are all sorts of potential causes of failure,” Darwin says. “At this point, speculation is not helpful for anybody.”

Sometimes I can access the entire article, and at other times, only a few paragraphs; I hope you get access to all of it as it provides a lot of information.

The Surfside news puts this research from Northwestern University (Chicago, Illinois) into much sharper relief than might otherwise be the case. (Further on I have some information about the difference between cement and concrete and how cement leads to concrete.)

Smart cement for more durable roads and cities

Coincidentally, just days before the Miami Beach building collapse, a June 21, 2021 Northwestern University news release (also on EurekAlert), announced research into improving water and fracture resistance in cement,

Forces of nature have been outsmarting the materials we use to build our infrastructure since we started producing them. Ice and snow turn major roads into rubble every year; foundations of houses crack and crumble, in spite of sturdy construction. In addition to the tons of waste produced by broken bits of concrete, each lane-mile of road costs the U.S. approximately $24,000 per year to keep it in good repair.

Engineers tackling this issue with smart materials typically enhance the function of materials by increasing the amount of carbon, but doing so makes materials lose some mechanical performance. By introducing nanoparticles into ordinary cement, Northwestern University researchers have formed a smarter, more durable and highly functional cement.

The research was published today (June 21 [2021]) in the journal Philosophical Transactions of the Royal Society A.

With cement being the most widely consumed material globally and the cement industry accounting for 8% of human-caused greenhouse gas emissions, civil and environmental engineering professor Ange-Therese Akono turned to nanoreinforced cement to look for a solution. Akono, the lead author on the study and an assistant professor in the McCormick School of Engineering, said nanomaterials reduce the carbon footprint of cement composites, but until now, little was known about its impact on fracture behavior.

“The role of nanoparticles in this application has not been understood before now, so this is a major breakthrough,” Akono said. “As a fracture mechanics expert by training, I wanted to understand how to change cement production to enhance the fracture response.”

Traditional fracture testing, in which a series of light beams is cast onto a large block of material, involves lots of time and materials and seldom leads to the discovery of new materials.

By using an innovative method called scratch testing, Akono’s lab efficiently formed predictions on the material’s properties in a fraction of the time. The method tests fracture response by applying a conical probe with increasing vertical force against the surface of microscopic bits of cement. Akono, who developed the novel method during her Ph.D. work, said it requires less material and accelerates the discovery of new ones.

“I was able to look at many different materials at the same time,” Akono said. “My method is applied directly at the micrometer and nanometer scales, which saves a considerable amount of time. And then based on this, we can understand how materials behave, how they crack and ultimately predict their resistance to fracture.”

Predictions formed through scratch tests also allow engineers to make changes to materials that enhance their performance at the larger scale. In the paper, graphene nanoplatelets, a material rapidly gaining popularity in forming smart materials, were used to improve the resistance to fracture of ordinary cement. Incorporating a small amount of the nanomaterial also was shown to improve water transport properties including pore structure and water penetration resistance, with reported relative decreases of 76% and 78%, respectively.

Implications of the study span many fields, including building construction, road maintenance, sensor and generator optimization and structural health monitoring.

By 2050, the United Nations predicts two-thirds of the world population will be concentrated in cities. Given the trend toward urbanization, cement production is expected to skyrocket.

Introducing green concrete that employs lighter, higher-performing cement will reduce its overall carbon footprint by extending maintenance schedules and reducing waste.

Alternately, smart materials allow cities to meet the needs of growing populations in terms of connectivity, energy and multifunctionality. Carbon-based nanomaterials including graphene nanoplatelets are already being considered in the design of smart cement-based sensors for structural health monitoring.

Akono said she’s excited for both follow-ups to the paper in her own lab and the ways her research will influence others. She’s already working on proposals that look into using construction waste to form new concrete and is considering “taking the paper further” by increasing the fraction of nanomaterial that cement contains.

“I want to look at other properties like understanding the long-term performance,” Akono said. “For instance, if you have a building made of carbon-based nanomaterials, how can you predict the resistance in 10, 20 even 40 years?”

The study, “Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing,” was supported by the National Science Foundation Division of Civil, Mechanical and Manufacturing Innovation (award number 18929101).

Akono will give a talk on the paper at The Royal Society’s October [2021] meeting, “A Cracking Approach to Inventing Tough New Materials: Fracture Stranger Than Friction,” which will highlight major advances in fracture mechanics from the past century.

I don’t often include these kinds of photos (one or more of the researchers posing (sometimes holding something) for the camera but I love the professor’s first name, Ange-Therese (which means angel in French, I don’t know if she ever uses the French spelling for Thérèse),

Caption: Professor Ange-Therese Akono holds a sample of her smart cement. Credit: Northwestern University

Here’s a link to and a citation for the paper,

Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing by Ange-Therese Akono. Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences 2021 379 (2203): 20200288 DOI: 10.1098/rsta.2020.0288 Published June 21, 2021

This paper appears to be open access.

Cement vs. concrete

Andrew Logan’s April 3, 2020 article for MIT (Massachusetts Institute of Technology) News is a very readable explanation of how cement and concrete differ and how they are related,

There’s a lot the average person doesn’t know about concrete. For example, it’s porous; it’s the world’s most-used material after water; and, perhaps most fundamentally, it’s not cement.

Though many use “cement” and “concrete” interchangeably, they actually refer to two different — but related — materials: Concrete is a composite made from several materials, one of which is cement. [emphasis mine]

Cement production begins with limestone, a sedimentary rock. Once quarried, it is mixed with a silica source, such as industrial byproducts slag or fly ash, and gets fired in a kiln at 2,700 degrees Fahrenheit. What comes out of the kiln is called clinker. Cement plants grind clinker down to an extremely fine powder and mix in a few additives. The final result is cement.

“Cement is then brought to sites where it is mixed with water, where it becomes cement paste,” explains Professor Franz-Josef Ulm, faculty director of the MIT Concrete Sustainability Hub (CSHub). “If you add sand to that paste it becomes mortar. And if you add to the mortar large aggregates — stones of a diameter of up to an inch — it becomes concrete.”

Final thoughts

I offer my sympathies to the folks affected by the building collapse and my hopes that research will lead the way to more durable cement and, ultimately, concrete buildings.

Cortical spheroids (like mini-brains) could unlock (larger) brain’s mysteries

A March 19, 2021 Northwestern University news release on EurekAlert announces the creation of a device designed to monitor brain organoids (for anyone unfamiliar with brain organoids there’s more information after the news),

A team of scientists, led by researchers at Northwestern University, Shirley Ryan AbilityLab and the University of Illinois at Chicago (UIC), has developed novel technology promising to increase understanding of how brains develop, and offer answers on repairing brains in the wake of neurotrauma and neurodegenerative diseases.

Their research is the first to combine the most sophisticated 3-D bioelectronic systems with highly advanced 3-D human neural cultures. The goal is to enable precise studies of how human brain circuits develop and repair themselves in vitro. The study is the cover story for the March 19 [March 17, 2021 according to the citation] issue of Science Advances.

The cortical spheroids used in the study, akin to “mini-brains,” were derived from human-induced pluripotent stem cells. Leveraging a 3-D neural interface system that the team developed, scientists were able to create a “mini laboratory in a dish” specifically tailored to study the mini-brains and collect different types of data simultaneously. Scientists incorporated electrodes to record electrical activity. They added tiny heating elements to either keep the brain cultures warm or, in some cases, intentionally overheated the cultures to stress them. They also incorporated tiny probes — such as oxygen sensors and small LED lights — to perform optogenetic experiments. For instance, they introduced genes into the cells that allowed them to control the neural activity using different-colored light pulses.

This platform then enabled scientists to perform complex studies of human tissue without directly involving humans or performing invasive testing. In theory, any person could donate a limited number of their cells (e.g., blood sample, skin biopsy). Scientists can then reprogram these cells to produce a tiny brain spheroid that shares the person’s genetic identity. The authors believe that, by combining this technology with a personalized medicine approach using human stem cell-derived brain cultures, they will be able to glean insights faster and generate better, novel interventions.

“The advances spurred by this research will offer a new frontier in the way we study and understand the brain,” said Shirley Ryan AbilityLab’s Dr. Colin Franz, co-lead author on the paper who led the testing of the cortical spheroids. “Now that the 3-D platform has been developed and validated, we will be able to perform more targeted studies on our patients recovering from neurological injury or battling a neurodegenerative disease.”

Yoonseok Park, postdoctoral fellow at Northwestern University and co-lead author, added, “This is just the beginning of an entirely new class of miniaturized, 3-D bioelectronic systems that we can construct to expand the capacity of the regenerative medicine field. For example, our next generation of device will support the formation of even more complex neural circuits from brain to muscle, and increasingly dynamic tissues like a beating heart.”

Current electrode arrays for tissue cultures are 2-D, flat and unable to match the complex structural designs found throughout nature, such as those found in the human brain. Moreover, even when a system is 3-D, it is extremely challenging to incorporate more than one type of material into a small 3-D structure. With this advance, however, an entire class of 3-D bioelectronics devices has been tailored for the field of regenerative medicine.

“Now, with our small, soft 3-D electronics, the capacity to build devices that mimic the complex biological shapes found in the human body is finally possible, providing a much more holistic understanding of a culture,” said Northwestern’s John Rogers, who led the technology development using technology similar to that found in phones and computers. “We no longer have to compromise function to achieve the optimal form for interfacing with our biology.”

As a next step, scientists will use the devices to better understand neurological disease, test drugs and therapies that have clinical potential, and compare different patient-derived cell models. This understanding will then enable a better grasp of individual differences that may account for the wide variation of outcomes seen in neurological rehabilitation.

“As scientists, our goal is to make laboratory research as clinically relevant as possible,” said Kristen Cotton, research assistant in Dr. Franz’s lab. “This 3-D platform opens the door to new experiments, discovery and scientific advances in regenerative neurorehabilitation medicine that have never been possible.”

Caption: Three dimensional multifunctional neural interfaces for cortical spheroids and engineered assembloids Credit: Northwestern University

As for what brain ogranoids might be, Carl Zimmer in an Aug. 29, 2019 article for the New York Times provides an explanation,

Organoids Are Not Brains. How Are They Making Brain Waves?

Two hundred and fifty miles over Alysson Muotri’s head, a thousand tiny spheres of brain cells were sailing through space.

The clusters, called brain organoids, had been grown a few weeks earlier in the biologist’s lab here at the University of California, San Diego. He and his colleagues altered human skin cells into stem cells, then coaxed them to develop as brain cells do in an embryo.

The organoids grew into balls about the size of a pinhead, each containing hundreds of thousands of cells in a variety of types, each type producing the same chemicals and electrical signals as those cells do in our own brains.

In July, NASA packed the organoids aboard a rocket and sent them to the International Space Station to see how they develop in zero gravity.

Now the organoids were stowed inside a metal box, fed by bags of nutritious broth. “I think they are replicating like crazy at this stage, and so we’re going to have bigger organoids,” Dr. Muotri said in a recent interview in his office overlooking the Pacific.

What, exactly, are they growing into? That’s a question that has scientists and philosophers alike scratching their heads.

On Thursday, Dr. Muotri and his colleagues reported that they  have recorded simple brain waves in these organoids. In mature human brains, such waves are produced by widespread networks of neurons firing in synchrony. Particular wave patterns are linked to particular forms of brain activity, like retrieving memories and dreaming.

As the organoids mature, the researchers also found, the waves change in ways that resemble the changes in the developing brains of premature babies.

“It’s pretty amazing,” said Giorgia Quadrato, a neurobiologist at the University of Southern California who was not involved in the new study. “No one really knew if that was possible.”

But Dr. Quadrato stressed it was important not to read too much into the parallels. What she, Dr. Muotri and other brain organoid experts build are clusters of replicating brain cells, not actual brains.

If you have the time, I recommend reading Zimmer’s article in its entirety. Perhaps not coincidentally, Zimmer has an excerpt titled “Lab-Grown Brain Organoids Aren’t Alive. But They’re Not Not Alive, Either.” published in Slate.com,

From Life’s Edge: The Search For What It Means To Be Alive by Carl Zimmer, published by Dutton, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2021 by Carl Zimmer.

Cleber Trujillo led me to a windowless room banked with refrigerators, incubators, and microscopes. He extended his blue-gloved hands to either side and nearly touched the walls. “This is where we spend half our day,” he said.

In that room Trujillo and a team of graduate students raised a special kind of life. He opened an incubator and picked out a clear plastic box. Raising it above his head, he had me look up at it through its base. Inside the box were six circular wells, each the width of a cookie and filled with what looked like watered-down grape juice. In each well 100 pale globes floated, each the size of a housefly head.

Getting back to the research about monitoring brain organoids, here’s a link to and a citation for the paper about cortical spheroids,

Three-dimensional, multifunctional neural interfaces for cortical spheroids and engineered assembloids by Yoonseok Park, Colin K. Franz, Hanjun Ryu, Haiwen Luan, Kristen Y. Cotton, Jong Uk Kim, Ted S. Chung, Shiwei Zhao, Abraham Vazquez-Guardado, Da Som Yang, Kan Li, Raudel Avila, Jack K. Phillips, Maria J. Quezada, Hokyung Jang, Sung Soo Kwak, Sang Min Won, Kyeongha Kwon, Hyoyoung Jeong, Amay J. Bandodkar, Mengdi Han, Hangbo Zhao, Gabrielle R. Osher, Heling Wang, KunHyuck Lee, Yihui Zhang, Yonggang Huang, John D. Finan and John A. Rogers. Science Advances 17 Mar 2021: Vol. 7, no. 12, eabf9153 DOI: 10.1126/sciadv.abf9153

This paper appears to be open access.

According to a March 22, 2021 posting on the Shirley Riley AbilityLab website, the paper is featured on the front cover of Science Advances (vol. 7 no. 12).

Transplanting healthy neurons could be possible with walking molecules and 3D printing

A February 23, 2021 news item on ScienceDaily announces work which may lead to healing brain injuries and diseases,

Imagine if surgeons could transplant healthy neurons into patients living with neurodegenerative diseases or brain and spinal cord injuries. And imagine if they could “grow” these neurons in the laboratory from a patient’s own cells using a synthetic, highly bioactive material that is suitable for 3D printing.

By discovering a new printable biomaterial that can mimic properties of brain tissue, Northwestern University researchers are now closer to developing a platform capable of treating these conditions using regenerative medicine.

A February 22, 2021 Northwestern University news release (also received by email and available on EurekAlert) by Lila Reynolds, which originated the news item, delves further into self-assembling ‘walking’ molecules and the nanofibers resulting in a new material designed to promote the growth of healthy neurons,

A key ingredient to the discovery is the ability to control the self-assembly processes of molecules within the material, enabling the researchers to modify the structure and functions of the systems from the nanoscale to the scale of visible features. The laboratory of Samuel I. Stupp published a 2018 paper in the journal Science which showed that materials can be designed with highly dynamic molecules programmed to migrate over long distances and self-organize to form larger, “superstructured” bundles of nanofibers.

Now, a research group led by Stupp has demonstrated that these superstructures can enhance neuron growth, an important finding that could have implications for cell transplantation strategies for neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, as well as spinal cord injury.

“This is the first example where we’ve been able to take the phenomenon of molecular reshuffling we reported in 2018 and harness it for an application in regenerative medicine,” said Stupp, the lead author on the study and the director of Northwestern’s Simpson Querrey Institute. “We can also use constructs of the new biomaterial to help discover therapies and understand pathologies.

Walking molecules and 3D printing

The new material is created by mixing two liquids that quickly become rigid as a result of interactions known in chemistry as host-guest complexes that mimic key-lock interactions among proteins, and also as the result of the concentration of these interactions in micron-scale regions through a long scale migration of “walking molecules.”

The agile molecules cover a distance thousands of times larger than themselves in order to band together into large superstructures. At the microscopic scale, this migration causes a transformation in structure from what looks like an uncooked chunk of ramen noodles into ropelike bundles.

“Typical biomaterials used in medicine like polymer hydrogels don’t have the capabilities to allow molecules to self-assemble and move around within these assemblies,” said Tristan Clemons, a research associate in the Stupp lab and co-first author of the paper with Alexandra Edelbrock, a former graduate student in the group. “This phenomenon is unique to the systems we have developed here.”

Furthermore, as the dynamic molecules move to form superstructures, large pores open that allow cells to penetrate and interact with bioactive signals that can be integrated into the biomaterials.

Interestingly, the mechanical forces of 3D printing disrupt the host-guest interactions in the superstructures and cause the material to flow, but it can rapidly solidify into any macroscopic shape because the interactions are restored spontaneously by self-assembly. This also enables the 3D printing of structures with distinct layers that harbor different types of neural cells in order to study their interactions.

Signaling neuronal growth

The superstructure and bioactive properties of the material could have vast implications for tissue regeneration. Neurons are stimulated by a protein in the central nervous system known as brain-derived neurotrophic factor (BDNF), which helps neurons survive by promoting synaptic connections and allowing neurons to be more plastic. BDNF could be a valuable therapy for patients with neurodegenerative diseases and injuries in the spinal cord but these proteins degrade quickly in the body and are expensive to produce.

One of the molecules in the new material integrates a mimic of this protein that activates its receptor known as Trkb, and the team found that neurons actively penetrate the large pores and populate the new biomaterial when the mimetic signal is present. This could also create an environment in which neurons differentiated from patient-derived stem cells mature before transplantation.

Now that the team has applied a proof of concept to neurons, Stupp believes he could now break into other areas of regenerative medicine by applying different chemical sequences to the material. Simple chemical changes in the biomaterials would allow them to provide signals for a wide range of tissues.

“Cartilage and heart tissue are very difficult to regenerate after injury or heart attacks, and the platform could be used to prepare these tissues in vitro from patient-derived cells,” Stupp said. “These tissues could then be transplanted to help restore lost functions. Beyond these interventions, the materials could be used to build organoids to discover therapies or even directly implanted into tissues for regeneration since they are biodegradable.”

Here’s a link to and a citation for the paper,

Superstructured Biomaterials Formed by Exchange Dynamics and Host–Guest Interactions in Supramolecular Polymers by Alexandra N. Edelbrock, Tristan D. Clemons, Stacey M. Chin, Joshua J. W. Roan, Eric P. Bruckner, Zaida Álvarez, Jack F. Edelbrock, Kristen S. Wek, Samuel I. Stupp. Advanced Science DOI: https://doi.org/10.1002/advs.202004042 First published: 22 February 2021

This paper is open access.

3D-printed graphene sensors for highly sensitive food freshness detection

I love the opening line (lede). From a June 29, 2020 news item on Nanowerk,

Researchers dipped their new, printed sensors into tuna broth and watched the readings.

It turned out the sensors – printed with high-resolution aerosol jet printers on a flexible polymer film and tuned to test for histamine, an allergen and indicator of spoiled fish and meat – can detect histamine down to 3.41 parts per million.

The U.S. Food and Drug Administration has set histamine guidelines of 50 parts per million in fish, making the sensors more than sensitive enough to track food freshness and safety.

I find using 3D-printing techniques to produce graphene, a 2-d material, intriguing. Apparently, the technique is cheaper and offers an advantage as it allows for greater precision than other techniques (inkjet printing, chemical vapour depostion [CVD], etc.)

Here’s more detail from a June 25, 2020 Iowa State University news release (also on EurekAlert but published June 29, 2020), which originated the news item,

Making the sensor technology possible is graphene, a supermaterial that’s a carbon honeycomb just an atom thick and known for its strength, electrical conductivity, flexibility and biocompatibility. Making graphene practical on a disposable food-safety sensor is a low-cost, aerosol-jet-printing technology that’s precise enough to create the high-resolution electrodes necessary for electrochemical sensors to detect small molecules such as histamine.

“This fine resolution is important,” said Jonathan Claussen, an associate professor of mechanical engineering at Iowa State University and one of the leaders of the research project. “The closer we can print these electrode fingers, in general, the higher the sensitivity of these biosensors.”

Claussen and the other project leaders – Carmen Gomes, an associate professor of mechanical engineering at Iowa State; and Mark Hersam, the Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University in Evanston, Illinois – have recently reported their sensor discovery in a paper published online by the journal 2D Materials. (…)

The paper describes how graphene electrodes were aerosol jet printed on a flexible polymer and then converted to histamine sensors by chemically binding histamine antibodies to the graphene. The antibodies specifically bind histamine molecules.

The histamine blocks electron transfer and increases electrical resistance, Gomes said. That change in resistance can be measured and recorded by the sensor.

“This histamine sensor is not only for fish,” Gomes said. “Bacteria in food produce histamine. So it can be a good indicator of the shelf life of food.”

The researchers believe the concept will work to detect other kinds of molecules, too.

“Beyond the histamine case study presented here, the (aerosol jet printing) and functionalization process can likely be generalized to a diverse range of sensing applications including environmental toxin detection, foodborne pathogen detection, wearable health monitoring, and health diagnostics,” they wrote in their research paper.

For example, by switching the antibodies bonded to the printed sensors, they could detect salmonella bacteria, or cancers or animal diseases such as avian influenza, the researchers wrote.

Claussen, Hersam and other collaborators (…) have demonstrated broader application of the technology by modifying the aerosol-jet-printed sensors to detect cytokines, or markers of inflammation. The sensors, as reported in a recent paper published by ACS Applied Materials & Interfaces, can monitor immune system function in cattle and detect deadly and contagious paratuberculosis at early stages.

Claussen, who has been working with printed graphene for years, said the sensors have another characteristic that makes them very useful: They don’t cost a lot of money and can be scaled up for mass production.

“Any food sensor has to be really cheap,” Gomes said. “You have to test a lot of food samples and you can’t add a lot of cost.”

Claussen and Gomes know something about the food industry and how it tests for food safety. Claussen is chief scientific officer and Gomes is chief research officer for NanoSpy Inc., a startup company based in the Iowa State University Research Park that sells biosensors to food processing companies.

They said the company is in the process of licensing this new histamine and cytokine sensor technology.

It, after all, is what they’re looking for in a commercial sensor. “This,” Claussen said, “is a cheap, scalable, biosensor platform.”

Here’s a link to and a citation for the two papers mentioned in the news release,

Aerosol-jet-printed graphene electrochemical histamine sensors for food safety monitoring by Kshama Parate, Cícero C Pola, Sonal V Rangnekar, Deyny L Mendivelso-Perez, Emily A Smith, Mark C Hersam, Carmen L Gomes and Jonathan C Claussen. 2D Materials, Volume 7, Number 3 DOI https://doi.org/10.1088/2053-1583/ab8919 Published 10 June 2020 • © 2020 IOP Publishing Ltd

Aerosol-Jet-Printed Graphene Immunosensor for Label-Free Cytokine Monitoring in Serum by Kshama Parate, Sonal V. Rangnekar, Dapeng Jing, Deyny L. Mendivelso-Perez, Shaowei Ding, Ethan B. Secor, Emily A. Smith, Jesse M. Hostetter, Mark C. Hersam, and Jonathan C. Claussen. ACS Appl. Mater. Interfaces 2020, 12, 7, 8592–8603 DOI: https://doi.org/10.1021/acsami.9b22183 Publication Date: February 10, 2020 Copyright © 2020 American Chemical Society

Both papers are behind paywalls.

You can find the NanoSpy website here.

Shining a light on flurocarbon bonds and robotic ‘soft’ matter research

Both of these news bits are concerned with light for one reason or another.

Rice University (Texas, US) and breaking fluorocarbon bonds

The secret to breaking fluorocarbon bonds is light according to a June 22, 2020 news item on Nanowerk,

Rice University engineers have created a light-powered catalyst that can break the strong chemical bonds in fluorocarbons, a group of synthetic materials that includes persistent environmental pollutants.

A June 22, 2020 Rice University news release (also on EurekAlert), which originated the news item, describes the work in greater detail,

In a study published this month in Nature Catalysis, Rice nanophotonics pioneer Naomi Halas and collaborators at the University of California, Santa Barbara (UCSB) and Princeton University showed that tiny spheres of aluminum dotted with specks of palladium could break carbon-fluorine (C-F) bonds via a catalytic process known as hydrodefluorination in which a fluorine atom is replaced by an atom of hydrogen.

The strength and stability of C-F bonds are behind some of the 20th century’s most recognizable chemical brands, including Teflon, Freon and Scotchgard. But the strength of those bonds can be problematic when fluorocarbons get into the air, soil and water. Chlorofluorocarbons, or CFCs, for example, were banned by international treaty in the 1980s after they were found to be destroying Earth’s protective ozone layer, and other fluorocarbons were on the list of “forever chemicals” targeted by a 2001 treaty.

“The hardest part about remediating any of the fluorine-containing compounds is breaking the C-F bond; it requires a lot of energy,” said Halas, an engineer and chemist whose Laboratory for Nanophotonics (LANP) specializes in creating and studying nanoparticles that interact with light.

Over the past five years, Halas and colleagues have pioneered methods for making “antenna-reactor” catalysts that spur or speed up chemical reactions. While catalysts are widely used in industry, they are typically used in energy-intensive processes that require high temperature, high pressure or both. For example, a mesh of catalytic material is inserted into a high-pressure vessel at a chemical plant, and natural gas or another fossil fuel is burned to heat the gas or liquid that’s flowed through the mesh. LANP’s antenna-reactors dramatically improve energy efficiency by capturing light energy and inserting it directly at the point of the catalytic reaction.

In the Nature Catalysis study, the energy-capturing antenna is an aluminum particle smaller than a living cell, and the reactors are islands of palladium scattered across the aluminum surface. The energy-saving feature of antenna-reactor catalysts is perhaps best illustrated by another of Halas’ previous successes: solar steam. In 2012, her team showed its energy-harvesting particles could instantly vaporize water molecules near their surface, meaning Halas and colleagues could make steam without boiling water. To drive home the point, they showed they could make steam from ice-cold water.

The antenna-reactor catalyst design allows Halas’ team to mix and match metals that are best suited for capturing light and catalyzing reactions in a particular context. The work is part of the green chemistry movement toward cleaner, more efficient chemical processes, and LANP has previously demonstrated catalysts for producing ethylene and syngas and for splitting ammonia to produce hydrogen fuel.

Study lead author Hossein Robatjazi, a Beckman Postdoctoral Fellow at UCSB who earned his Ph.D. from Rice in 2019, conducted the bulk of the research during his graduate studies in Halas’ lab. He said the project also shows the importance of interdisciplinary collaboration.

“I finished the experiments last year, but our experimental results had some interesting features, changes to the reaction kinetics under illumination, that raised an important but interesting question: What role does light play to promote the C-F breaking chemistry?” he said.

The answers came after Robatjazi arrived for his postdoctoral experience at UCSB. He was tasked with developing a microkinetics model, and a combination of insights from the model and from theoretical calculations performed by collaborators at Princeton helped explain the puzzling results.

“With this model, we used the perspective from surface science in traditional catalysis to uniquely link the experimental results to changes to the reaction pathway and reactivity under the light,” he said.

The demonstration experiments on fluoromethane could be just the beginning for the C-F breaking catalyst.

“This general reaction may be useful for remediating many other types of fluorinated molecules,” Halas said.

Caption: An artist’s illustration of the light-activated antenna-reactor catalyst Rice University engineers designed to break carbon-fluorine bonds in fluorocarbons. The aluminum portion of the particle (white and pink) captures energy from light (green), activating islands of palladium catalysts (red). In the inset, fluoromethane molecules (top) comprised of one carbon atom (black), three hydrogen atoms (grey) and one fluorine atom (light blue) react with deuterium (yellow) molecules near the palladium surface (black), cleaving the carbon-fluorine bond to produce deuterium fluoride (right) and monodeuterated methane (bottom). Credit: H. Robatjazi/Rice University

Here’s a link to and a citation for the paper,

Plasmon-driven carbon–fluorine (C(sp3)–F) bond activation with mechanistic insights into hot-carrier-mediated pathways by Hossein Robatjazi, Junwei Lucas Bao, Ming Zhang, Linan Zhou, Phillip Christopher, Emily A. Carter, Peter Nordlander & Naomi J. Halas. Nature Catalysis (2020) DOI: https://doi.org/10.1038/s41929-020-0466-5 Published: 08 June 2020

This paper is behind a paywall.

Northwestern University (Illinois, US) brings soft robots to ‘life’

This June 22, 2020 news item on ScienceDaily reveals how scientists are getting soft robots to mimic living creatures,

Northwestern University researchers have developed a family of soft materials that imitates living creatures.

When hit with light, the film-thin materials come alive — bending, rotating and even crawling on surfaces.

A June 22, 2020 Northwestern University news release (also on EurekAlert) by Amanda Morris, which originated the news item, delves further into the details,

Called “robotic soft matter by the Northwestern team,” the materials move without complex hardware, hydraulics or electricity. The researchers believe the lifelike materials could carry out many tasks, with potential applications in energy, environmental remediation and advanced medicine.

“We live in an era in which increasingly smarter devices are constantly being developed to help us manage our everyday lives,” said Northwestern’s Samuel I. Stupp, who led the experimental studies. “The next frontier is in the development of new science that will bring inert materials to life for our benefit — by designing them to acquire capabilities of living creatures.”

The research will be published on June 22 [2020] in the journal Nature Materials.

Stupp is the Board of Trustees Professor of Materials Science and Engineering, Chemistry, Medicine and Biomedical Engineering at Northwestern and director of the Simpson Querrey Institute He has appointments in the McCormick School of Engineering, Weinberg College of Arts and Sciences and Feinberg School of Medicine. George Schatz, the Charles E. and Emma H. Morrison Professor of Chemistry in Weinberg, led computer simulations of the materials’ lifelike behaviors. Postdoctoral fellow Chuang Li and graduate student Aysenur Iscen, from the Stupp and Schatz laboratories, respectively, are co-first authors of the paper.

Although the moving material seems miraculous, sophisticated science is at play. Its structure comprises nanoscale peptide assemblies that drain water molecules out of the material. An expert in materials chemistry, Stupp linked the peptide arrays to polymer networks designed to be chemically responsive to blue light.

When light hits the material, the network chemically shifts from hydrophilic (attracts water) to hydrophobic (resists water). As the material expels the water through its peptide “pipes,” it contracts — and comes to life. When the light is turned off, water re-enters the material, which expands as it reverts to a hydrophilic structure.

This is reminiscent of the reversible contraction of muscles, which inspired Stupp and his team to design the new materials.

“From biological systems, we learned that the magic of muscles is based on the connection between assemblies of small proteins and giant protein polymers that expand and contract,” Stupp said. “Muscles do this using a chemical fuel rather than light to generate mechanical energy.”

For Northwestern’s bio-inspired material, localized light can trigger directional motion. In other words, bending can occur in different directions, depending on where the light is located. And changing the direction of the light also can force the object to turn as it crawls on a surface.

Stupp and his team believe there are endless possible applications for this new family of materials. With the ability to be designed in different shapes, the materials could play a role in a variety of tasks, ranging from environmental clean-up to brain surgery.

“These materials could augment the function of soft robots needed to pick up fragile objects and then release them in a precise location,” he said. “In medicine, for example, soft materials with ‘living’ characteristics could bend or change shape to retrieve blood clots in the brain after a stroke. They also could swim to clean water supplies and sea water or even undertake healing tasks to repair defects in batteries, membranes and chemical reactors.”

Fascinating, eh? No batteries, no power source, just light to power movement. For the curious, here’s a link to and a citation for the paper,

Supramolecular–covalent hybrid polymers for light-activated mechanical actuation by Chuang Li, Aysenur Iscen, Hiroaki Sai, Kohei Sato, Nicholas A. Sather, Stacey M. Chin, Zaida Álvarez, Liam C. Palmer, George C. Schatz & Samuel I. Stupp. Nature Materials (2020) DOI: https://doi.org/10.1038/s41563-020-0707-7 Published: 22 June 2020

This paper is behind a paywall.

Clean up oil spills with a smart sponge?

I love the part with the magnet,

All of the main points are made in the video but for those who like text, there’s a May 28, 2020 news item on phys.org describing this new smart sponge for cleaning up oil spills (Note: Links have been removed),

A Northwestern University-led [Chicago, Illinois, US] team has developed a highly porous smart sponge that selectively soaks up oil in water.

With an ability to absorb more than 30 times its weight in oil, the sponge could be used to inexpensively and efficiently clean up oil spills without harming marine life. After squeezing the oil out of the sponge, it can be reused many dozens of times without losing its effectiveness.

“Oil spills have devastating and immediate effects on the environment, human health and economy,” said Northwestern’s Vinayak Dravid, who led the research. “Although many spills are small and may not make the evening news, they are still profoundly invasive to the ecosystem and surrounding community. Our sponge can remediate these spills in a more economic, efficient and eco-friendly manner than any of the current state-of-the-art solutions.”

A May 28, 2020 Northwestern University news release (also on EurekAlert), which originated the news item, reveals (as did the video) the characteristics that make this smart sponge particularly interesting,

Oil spill clean-up is an expensive and complicated process that often harms marine life and further damages the environment. Currently used solutions include burning the oil, using chemical dispersants to breakdown oil into very small droplets, skimming oil floating on top of water and/or absorbing it with expensive, unrecyclable sorbents.

“Each approach has its own drawbacks and none are sustainable solutions,” Nandwana [Vikas Nandwana, a senior research associate in Dravid’s laboratory] said. “Burning increases carbon emissions and dispersants are terribly harmful for marine wildlife. Skimmers don’t work in rough waters or with thin layers of oil. And sorbents are not only expensive, but they generate a huge amount of physical waste — similar to the diaper landfill issue.”

The Northwestern solution bypasses these challenges by selectively absorbing oil and leaving clean water and unaffected marine life behind. The secret lies in a nanocomposite coating of magnetic nanostructures and a carbon-based substrate that is oleophilic (attracts oil), hydrophobic (resists water) and magnetic. The nanocomposite’s nanoporous 3D structure selectively interacts with and binds to the oil molecules, capturing and storing the oil until it is squeezed out. The magnetic nanostructures give the smart sponge two additional functionalities: controlled movement in the presence of an external magnetic field and desorption of adsorbed components, such as oil, in a simulated and remote manner.

The OHM (oleophilic hydrophobic magnetic) nanocomposite slurry can be used to coat any cheap, commercially available sponge. The researchers applied a thin coating of the slurry to the sponge, squeezed out the excess and let it dry. The sponge is quickly and easily converted into a smart sponge (or “OHM sponge”) with a selective affinity for oil.

Vinayak and his team tested the OHM sponge with many different types of crude oils of varying density and viscosity. The OHM sponge consistently absorbed up to 30 times its weight in oil, leaving the water behind. To mimic natural waves, researchers put the OHM sponge on a shaker submerged in water. Even after vigorous shaking, the sponge release less than 1% of its absorbed oil back into the water.

“Our sponge works effectively in diverse and extreme aquatic conditions that have different pH and salinity levels,” Dravid said. “We believe we can address a giga-ton problem with a nanoscale solution.”

“We are excited to introduce such smart sponges as an environmental remediation platform for selectively removing and recovering pollutants present in water, soil and air, such as excess nutrients, heavy metal contaminants, VOC/toxins and others,” Nandwana said. “The nanostructure coating can be tailored to selectively adsorb (and later desorb) these pollutants.”

The team also is working on another grade of OHM sponge that can selectively absorb (and later recover) excess dissolved nutrients, such as phosphates, from fertilizer runoff and agricultural pollution. Stephanie Ribet, a Ph.D. candidate in Dravid’s lab and paper coauthor is pursuing this topic. The team plans to develop and commercialize OHM technology for environmental clean-up.

Bravo to professor Vinayak Dravid and his team. I’m sure I’m not alone in wishing you and your team the best of luck as you continue to develop this remediation technology.

Here’s a link to and a citation for the paper,

OHM Sponge: A Versatile, Efficient, and Ecofriendly Environmental Remediation Platform by Vikas Nandwana, Stephanie M. Ribet, Roberto D. Reis, Yuyao Kuang, Yash More, and Vinayak P. Dravid. Ind. Eng. Chem. Res. 2020, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.iecr.0c01493 Publication Date:May 12, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Make electricity by flowing water over nanolayers of metal

Scientists at Northwestern University (Chicago, Illinois) and the California Institute of Technology (CalTech) have developed what could be a more sustainable way to produce electricity. From a July 31, 2019 news item on Nanowerk,

Scientists from Northwestern University and Caltech have produced electricity by simply flowing water over extremely thin layers of inexpensive metals, including iron, that have oxidized. These films represent an entirely new way of generating electricity and could be used to develop new forms of sustainable power production.

A July 31, 2019 Northwester University news release (also on EurekAlert) by Megan Fellman, which originated the news item, provides details that suggest this discovery could prove beneficial in medical implants, as well as, in solar cells,

The films have a conducting metal nanolayer (10 to 20 nanometers thick) that is insulated with an oxide layer (2 nanometers thick). Current is generated when pulses of rainwater and ocean water alternate and move across the nanolayers. The difference in salinity drags the electrons along in the metal below.

“It’s the oxide layer over the nanometal that really makes this device go,” said Franz M. Geiger, the Dow Professor of Chemistry in Northwestern’s Weinberg College of Arts and Sciences. “Instead of corrosion, the presence of the oxides on the right metals leads to a mechanism that shuttles electrons.”

The films are transparent, a feature that could be taken advantage of in solar cells. The researchers intend to study the method using other ionic liquids, including blood. Developments in this area could lead to use in stents and other implantable devices.

“The ease of scaling up the metal nanolayer to large areas and the ease with which plastics can be coated gets us to three-dimensional structures where large volumes of liquids can be used,” Geiger said. “Foldable designs that fit, for instance, into a backpack are a possibility as well. Given how transparent the films are, it’s exciting to think about coupling the metal nanolayers to a solar cell or coating the outside of building windows with metal nanolayers to obtain energy when it rains.”

The study, titled “Energy Conversion via Metal Nanolayers,” was published this week [on July 29, 2019] in the journal Proceedings of the National Academy of Sciences (PNAS).

Geiger is the study’s corresponding author; his Northwestern team conducted the experiments. Co-author Thomas Miller, professor of chemistry at Caltech, led a team that conducted atomistic simulations to study the device’s behavior at the atomic level.

The new method produces voltages and currents comparable to graphene-based devices reported to have efficiencies of around 30% — similar to other approaches under investigation (carbon nanotubes and graphene) but with a single-step fabrication from earth-abundant elements instead of multistep fabrication. This simplicity allows for scalability, rapid implementation and low cost. Northwestern has filed for a provisional patent.

Of the metals studied, the researchers found that iron, nickel and vanadium worked best. They tested a pure rust sample as a control experiment; it did not produce a current.

The mechanism behind the electricity generation is complex, involving ion adsorption and desorption, but it essentially works like this: The ions present in the rainwater/saltwater attract electrons in the metal beneath the oxide layer; as the water flows, so do those ions, and through that attractive force, they drag the electrons in the metal along with them, generating an electrical current.

“There are interesting prospects for a variety of energy and sustainability applications, but the real value is the new mechanism of oxide-metal electron transfer,” Geiger said. “The underlying mechanism appears to involve various oxidation states.”

The team used a process called physical vapor deposition (PVD), which turns normally solid materials into a vapor that condenses on a desired surface. PVD allowed them to deposit onto glass metal layers only 10 to 20 nanometers thick. An oxide layer then forms spontaneously in air. It grows to a thickness of 2 nanometers and then stops growing.

“Thicker films of metal don’t succeed — it’s a nano-confinement effect,” Geiger said. “We have discovered the sweet spot.”

When tested, the devices generated several tens of millivolts and several microamps per centimeter squared.

“For perspective, plates having an area of 10 square meters each would generate a few kilowatts per hour — enough for a standard U.S. home,” Miller said. “Of course, less demanding applications, including low-power devices in remote locations, are more promising in the near term.”

Here’s a link to and a citation for the paper,

Energy conversion via metal nanolayers by Mavis D. Boamah, Emilie H. Lozier, Jeongmin Kim, Paul E. Ohno, Catherine E. Walker, Thomas F. Miller III, and Franz M. Geiger. PNAS DOI: https://doi.org/10.1073/pnas.1906601116 First published July 29, 2019

This paper is behind a paywall.

Neural and technological inequalities

I’m always happy to see discussions about the social implications of new and emerging technologies. In this case, the discussion was held at the Fast Company (magazine) European Innovation Festival. KC Ifeanyi wrote a July 10, 2019 article for Fast Company highlighting a session between two scientists focusing on what I’ve termed ‘machine/flesh’ or is, sometimes, called a cyborg but not with these two scientists (Note: A link has been removed),

At the Fast Company European Innovation Festival today, scientists Moran Cerf and Riccardo Sabatini had a wide-ranging discussion on the implications of technology that can hack humanity. From ethical questions to looking toward human biology for solutions, here are some of the highlights:

The ethics of ‘neural inequality’

There are already chips that can be implanted in the brain to help recover bodily functions after a stroke or brain injury. However, what happens if (more likely when) a chip in your brain can be hacked or even gain internet access, essentially making it possible for some people (more likely wealthy people) to process information much more quickly than others?

“It’s what some call neural inequality,” says Cerf, a neuroscientist and business professor at the Kellogg School of Management and at the neuroscience program at Northwestern University. …

Opening new pathways to thought through bionics

Cerf mentioned a colleague who was born without his left hand. He engineered a bionic one that he can control with an app and that has the functionality of doing things no human hand can do, like rotating 360 degrees. As fun of a party trick as that is, Cerf brings up a good point in that his colleague’s brain is processing something we can’t, thereby possibly opening new pathways of thought.

“The interesting thing, and this is up to us to investigate, is his brain can think thoughts that you cannot think [emphasis mine] because he has a function you don’t have,” Cerf says. …

The innovation of your human body

As people look to advanced bionics to amplify their senses or abilities, Sabatini, chief data scientist at Orionis Biosciences, makes the argument that our biological bodies are far more advanced than we give them credit for. …

Democratizing tech’s edges

Early innovation so often comes with a high price tag. The cost of experimenting with nascent technology or running clinical trials can be exorbitant. And Sabatini believes democratizing that part of the process is where the true innovation will be. …

Earlier technology that changed our thinking and thoughts

This isn’t the first time that technology has altered our thinking and the kinds of thoughts we have as per ” brain can think thoughts that you cannot think.” According to Walter J. Ong’s 1982 book, ‘Orality and Literacy’,that’s what writing did to us; it changed our thinking and the kinds of thoughts we have.

It took me quite a while to understand ‘writing’ as a technology, largely due to how much I took it for granted. Once I made that leap, it changed how I understood the word technology. Then, the idea that ‘writing’ could change your brain didn’t require as dramatic a leap although it fundamentally altered my concept of the relationship between technology and humans. Up to that time, I had viewed technology as an instrument that allowed me to accomplish goals (e.g., driving a car from point a to point b) but it had very little impact on me as a person.

You can find out more about Walter J. Ong and his work in his Wikipedia entry. Pay special attention to the section about, Orality and Literacy.

Who’s talking about technology and our thinking?

The article about the scientists (Cerf and Sabatini) at the Fast Company European Innovation Festival (held July 9 -10, 2019 in Milan, Italy) never mentions cyborgs. Presumably, neither did Sabatini or Cerf. It seems odd. Two thinkers were discussing ‘neural inequality’ and there was no mention of a cyborg (human and machine joined together).

Interestingly, the lead sponsor for this innovation festival was Gucci. That company would not have been my first guess or any other guess for that matter as having an interest in neural inequality.

So, Gucci sponsored a festival that is not not cheap. A two-day pass was $1600. (early birds got a discount of $457) and a ‘super’ pass was $2,229 (with an early bird discount of $629). So, you didn’t get into the room unless you had a fair chunk of change and time.

The tension, talking about inequality at a festival or other venue that most people can’t afford to attend, is discussed at more length in Anand Giridharadas’s 2018 book, ‘Winners Take All; The Elite Charade of Changing the World’.

It’s not just who gets to discuss ‘neural inequality’, it’s when you get to discuss it, which affects how the discussion is framed.

There aren’t an easy answers to these questions but I find the easy assumption that the wealthy and the science and technology communities get first dibs at the discussion a little disconcerting while being perfectly predictable.

On the plus side, there are artists and others who have jumped in and started the discussion by turning themselves into cyborgs. This August 14, 2015 article (Body-hackers: the people who turn themselves into cyborgs) by Oliver Wainwright for the Guardian is very informative and not for the faint of heart.

For the curious, I’ve been covering these kinds of stories here since 2009. The category ‘human enhancement’ and the search term ‘machine/flesh’ should provide you with an assortment of stories on the topic.

There’s no ‘I’ in team: coaching scientists to work together

While it’s true enough in English where you don’t spell the word team with the letter ‘I’, that’s not the case in French where the word is ‘equipe’. it makes me wonder how many other languages in the world have an ‘I’ in team.

Moving on. This English language saying is true enough in its way but there is no team unless you have a group of ‘I’s’ and the trick is getting them to work together as a July 18, 2019 Northwestern University news release (received via email) about a new online training tool notes,

Coaching scientists to play well together

Free tool shows how to avoid fights over data and authorship conflicts   

‘You stole my idea’ or ‘I’m not getting credit for my work’ are common disputes
Only tool validated by research to help scientists collaborate smoothly
Many NSF [US National Science Foundation] and NIH [US National Institutes of Health] grants now require applicants to show readiness for team science
Scientists can’t do it on their own

CHICAGO — When scientists from different disciplines collaborate – as is increasingly necessary to confront the complexity of challenging research problems – interpersonal tussles often arise. One scientist may accuse another of stealing her ideas. Or, a researcher may feel he is not getting credit for his work or doesn’t have access to important data. 
 
“Interdisciplinary team science is now the state of the art across all branches of science and engineering,” said Bonnie Spring, professor of preventive medicine at Northwestern University Feinberg School of Medicine. “But very few scientists have been trained to work with others outside of their own disciplinary silo.”
 
The skill is critical because many National Institute[s] of Health and National Science Foundationgrants require applicants to show readiness for team science.
 
A free, online training tool developed by Northwestern — teamscience.net — has been been proven to help scientists develop skills to work with other scientists outside their own discipline. 
 
A new study led by Spring showed scientists who completed the program’s modules – called COALESCE – significantly boosted their knowledge about team science and increased their self-confidence about being able to successfully work in scientific teams. Most people who completed one or more modules (84%) said that the experience of taking the modules was very likely to positively impact their future research.
 
The study will be published July 18 [2019] in the Journal of Clinical and Translational Science.
 
There are few training resources to teach scientists how to collaborate, and the ones that are available don’t have evidence of their effectiveness. Teamscience.net is the only free, validated-by-research tool available to anyone at any time. 
 
Almost 1,000 of the COALESCE users opted voluntarily to respond to questions about the learning modules, providing information about how taking each module influenced team science knowledge, skills and attitudes.
 
‘You stole my idea’
 
The most common area of dispute among collaborating scientists is authorship concerns, such as accusations that one person stole ideas from another or that a contributor was not getting credit for his or her work, the study authors said. Other disputes arise around access to and analysis of data, utilization of materials or resources and the general direction of the research itself. Underlying all of these issues is a common failure to prepare for working collaboratively with other scientists. 
 
“Preparing in advance before starting to collaborate, often through the creation of a formal collaboration agreement document, is the best way to head off these types of disputes,” said Angela Pfammatter, assistant professor of preventive medicine at Feinberg and a coauthor on the paper.
  
Spring suggested “having scientists discuss their expectations of one another and the collaboration to prevent acrimonious conflicts.” 
 
Skills to play well together
 
These skills are critical to a successful scientific team, the authors said: 

The ability to choose team members who have the right mix of expertise, temperament and accessibility to round out a team. 
The ability to anticipate what could go wrong and to develop contingency plans in advance. 
The ability to manage conflict within the team 

The teamscience.net modules help scientists acquire these skills by letting them interact with different problem scenarios that can arise in team-based research. Scientists can try out different solutions and learn from mistakes in a safe, online environment. 
 
More than 16,000 people have accessed the resource in the past six years.  Demand for team science training is expected to increase as interdisciplinary teams set out to tackle some of science’s most challenging problems. 
 
Other Northwestern authors on the paper are Ekaterina Klyachko, Phillip Rak, H. Gene McFadden, Juned Siddique and Leland Bardsley. 
 
Funding support for COALESCE is from the National Institutes of Health, National Center for Advancing Translational Sciences grants 3UL1RR025741 and UL1TR001422 and its Office of Behavioral and Social Sciences Research.

i once got caught here on this blog between two warring scientists. My August 24, 2015 posting was a pretty standard one for me. Initially, it was one of my more minimalistic pieces with a copy of the text from a university news release announcing the research and a link to the academic paper. I can’t remember if the problem was which scientist was listed first and which was listed last but one of them took exception and contacted me explaining how it was wrong. (Note: These decisions are not made by me.) I did my best to fix whatever the problem was and then the other scientist contacted me. After the dust settled, I ended up with a dog’s breakfast for my posting and a new policy.

Getting back to COALESCE: I wish the Northwestern University researchers all the best as they look for ways to help scientists work together more smoothly and cooperatively.

Here’s a link to and a citation for the paper,

Online, cross-disciplinary team science training for health and medical professionals: Evaluation of COALESCE (teamscience.net) by Bonnie Spring, Ekaterina A. Klyachko, Phillip W. Rak, H. Gene McFadden, Donald Hedeker, Juned Siddique, Leland R. Bardsley, and Angela Fidler Pfammatter. Jurnal of Clinical and Translational Science DOI: https://doi.org/10.1017/cts.2019.383 Published online by Cambridge University Press: 18 July 2019

This paper is open access.

How do nanoparticles interact with the environment and with humans over time?

I meant to get this piece published sooner but good intentions don’t get you far.

At Northwestern University, scientists have researched the impact engineered nanoparticles (ENPs) might have as they enter the food chain. An October 18, 2019 Northwestern University news release (also on EurekAlert) by Megan Fellman describes research on an investigation of ENPs and their interaction with living organisms,

Personal electronic devices — smartphones, computers, TVs, tablets, screens of all kinds — are a significant and growing source of the world’s electronic waste. Many of these products use nanomaterials, but little is known about how these modern materials and their tiny particles interact with the environment and living things.

Now a research team of Northwestern University chemists and colleagues from the national Center for Sustainable Nanotechnology has discovered that when certain coated nanoparticles interact with living organisms it results in new properties that cause the nanoparticles to become sticky. Fragmented lipid coronas form on the particles, causing them to stick together and grow into long kelp-like strands. Nanoparticles with 5-nanometer diameters form long structures that are microns in size in solution. The impact on cells is not known.

“Why not make a particle that is benign from the beginning?” said Franz M. Geiger, professor of chemistry in Northwestern’s Weinberg College of Arts and Sciences. He led the Northwestern portion of the research.

“This study provides insight into the molecular mechanisms by which nanoparticles interact with biological systems,” Geiger said. “This may help us understand and predict why some nanomaterial/ligand coating combinations are detrimental to cellular organisms while others are not. We can use this to engineer nanoparticles that are benign by design.”

Using experiments and computer simulations, the research team studied how gold nanoparticles wrapped in strings having positively charged beads interact with a variety of bilayer membrane models. The researchers found that a nearly circular layer of lipids forms spontaneously around the particles. Formation of these “fragmented lipid coronas” have never been seen before to form from membranes.

The study points to solving problems with chemistry. Scientists can use the findings to design a better ligand coating for nanoparticles that avoids the ammonium-phosphate interaction, which causes the aggregation. (Ligands are used in nanomaterials for layering.)

The results will be published Oct. 18 [2018] in the journal Chem.

Geiger is the study’s corresponding author. Other authors include scientists from the Center for Sustainable Nanotechnology’s other institutional partners. Based at the University of Wisconsin-Madison, the center studies engineered nanomaterials and their interaction with the environment, including biological systems — both the negative and positive aspects.

“The nanoparticles pick up parts of the lipid cellular membrane like a snowball rolling in a snowfield, and they become sticky,” Geiger said. “This unintended effect happens because of the presence of the nanoparticle. It can bring lipids to places in cells where lipids are not meant to be.”

The experiments were conducted in idealized laboratory settings that nevertheless are relevant to environments found during the late summer in a landfill — at 21-22 degrees Celsius and a couple feet below ground, where soil and groundwater mix and the food chain begins.

By pairing spectroscopic and imaging experiments with atomistic and coarse-grain simulations, the researchers identified that ion pairing between the lipid head groups of biological membranes and the polycations’ ammonium groups in the nanoparticle wrapping leads to the formation of fragmented lipid coronas. These coronas engender new properties, including composition and stickiness, to the particles with diameters below 10 nanometers.

The study’s insights help predict the impact that the increasingly widespread use of engineered nanomaterials has on the nanoparticles’ fate once they enter the food chain, which many of them may eventually do.

“New technologies and mass consumer products are emerging that feature nanomaterials as critical operational components,” Geiger said. “We can upend the existing paradigm in nanomaterial production towards one in which companies design nanomaterials to be sustainable from the beginning, as opposed to risking expensive product recalls — or worse — down the road.” [emphases mine]

Here’s an image illustrating the work,

Caption: This is a computer simulation of a lipid corona around a 5-nanometer nanoparticle showing ammonium-phosphate ion pairing. Credit: Northwestern University

The curious can find the paper here,

Lipid Corona Formation from Nanoparticle Interactions with Bilayers by Laura L. Olenick, Julianne M. Troiano, Ariane Vartanian, Eric S. Melby, Arielle C. Mensch, Leili Zhang, Jiewei Hong, Oluwaseun Mesele, Tian Qiu, Jared Bozich, Samuel Lohse, Xi Zhang, Thomas R. Kuech, Augusto Millevolte, Ian Gunsolus, Alicia C. McGeachy, Merve Doğangün, Tianzhe Li, Dehong Hu, Stephanie R. Walter, Aurash Mohaimani, Angela Schmoldt, Marco D. Torelli, Katherine R. Hurley, Joe Dalluge, Gene Chong, Z. Vivian Feng, Christy L. Haynes, Robert J. Hamers, Joel A. Pedersen, Qiang Cui, Rigoberto Hernandez, Rebecca Klaper, Galya Orr, Catherine J. Murphy, Franz M. Geiger. Chem Volume 4, ISSUE 11, P2709-2723, November 08, 2018 DOI:https://doi.org/10.1016/j.chempr.2018.09.018 Published:October 18, 2018

This paper is behind a paywall.