Symposium X: Frontiers of Materials Research

Frederick-mauFrederick Mau, Toyota Motor North America, Inc.
Intellectual Property Filing Strategy, Portfolio Management and Licensing of Material-Related Technologies

At Toyota, Frederick Mau aims to examine every idea for potential filing. He bases his decision on whether the invention is new, and if it is good for the company. According to the company, Mau took them from 28 US patents in 2006 to the cumulative number of 1,540 in 2016.

One of the recent patents Toyota holds is for omnidirectional structural color or pigment compounds that reflect specific wavelengths of light. The study began with modeling and then was taken to the laboratory which brought the company several patent files. Others accumulated in reference to this same invention due to improvements and new applications, so that the portfolio now contains 37 issued US patents.

Similarly, Toyota holds 64 issued US patents in their portfolio for nanomaterial synthesis and 33 issued US patents for bioactive cleaning materials. “When building a portfolio, not all the patents need to be huge and just kind of groundbreaking technology. There should be a few fundamental science,” Mau said, “but as you continue to work with the portfolio, you’re going to come across a lot of new improvements or applications and those can all be used.”

To file a patent, pointed questions need to be asked, Mau said, to help understand the various aspects of the invention, such as “What are the benefits?” “How does it work?” “Do you have data to back it up?” Data is essential, he said, particularly all of the empirical data.

With the increasing use of materials informatics comes new considerations for the patent attorney: “Who is the inventor?” “Can the resulting material be reproduced in a laboratory?” “What are the best routes for synthesis?” “Will the resulting material perform as predicted?” In the case of the pigment compounds, the simulations for the color pigments matched up to the laboratory results, so the patent process went well, Mau said, but this is not always the case.

After his presentation, Mau fielded numerous questions from the audience which can be viewed along with the presentation online through December 31st.


Symposium X: Frontiers of Materials Research

Reshma-shettyReshma Shetty, Ginkgo Bioworks, Inc.
Designing Biology

The onset of the COVID-19 pandemic may have heightened the general public’s awareness of two things: the dangers of biotechnology should someone release an uncontrollable virus as well as the marvels of biotechnology that enables researchers to rapidly (within a year vs 10 or 20 years) develop and distribute a vaccine. 

Reshma Shetty, co-founder of the synthetic biology company Ginkgo Bioworks, Inc. over 10 years ago, had been named at the same time by Forbes magazine as one of “Eight People Inventing the Future.” The future is here as Ginkgo Bioworks provides a bioengineering foundry to test and develop synthetic biology prototypes. Shetty said, “We design biology so that we can grow products rather than manufacture them.”

Among the projects Shetty described is a compostable plastic bag. The bag is made from a biological precursor (1,4 butanediol) that the E. coli bacterium had been engineered to produce. Other projects included the development of plant-based meats and designer bacteria crops that can fertilize themselves. These projects—all done in partnerships with other companies—contribute to building a bioeconomy.

To provide a sense of the enormous possibilities available in the emerging field of synthetic biology, Shetty displayed a metabolic map, giving a snapshot of different types of chemistry reactions that occur inside living organisms. The map shows tens of thousands of enzymes that can catalyze a reaction. “By simply selecting or engineering the right enzyme sequence, you can create exquisitely interesting new manufacturing methods using biology,” Shetty said. 

However, well aware of the public’s general distrust of biotechnology, Shetty’s company embarked on a project with the hopes of piquing their interest instead. Inspired by the movie Jurassic Park, Shetty’s group wondered what it would be like if visitors in a museum could smell an extinct plant. The way to go about this was to identify a plant that has recently become extinct so that they could still obtain samples. They chose the Mountain hibiscus (Hau Kuahiwi). They found a sample at Harvard University. From the very small sample, they were able to obtain fragments of DNA that they stitched together based on what they know from a particular class of enzymes in living plants that make fragrance compounds. “We made sort of a ‘part science-part artist’ rendering of what we think the Mountain hibiscus smelled like,” Shetty said. “The point of the project was not to scientifically recreate the scent of an extinct plant but really to help inspire the imagination for folks about what biology could do.” The research group distributed displays of their work to museums around the world.


Symposium X: Frontiers of Materials Research

Daniel G. Anderson, Massachusetts Institute of Technology

Biomaterials for the Therapeutic Delivery of Nucleic Acids, Genome Editing Tools, and Cells

“The first major area I’d like to discuss,” said Daniel G. Anderson, “is where we will get to talk about making drugs that can actually repair your DNA while you’re still using it.” This is the stuff of science fiction, he said, except that this work is real. “Imagine a nanoparticle that you might inject into your blood … that can travel through the body, reach that diseased liver, actually enter those cells, deliver therapeutic [treatment] that can specifically repair the DNA,” he said, and permanently repair the disease. One of the challenges, Anderson said, is how to get the nucleic acids or genome editing tools inside the body.

Certain organs are more amenable, he said. For example, the blood vessels in liver have small holes that allow nanoparticles inside. Nanoparticles can be made to carry nucleic acids that can encode different parts of the genome editing machinery. But turning nucleic acids into drugs is not easy, he said. In one example Anderson described success with RNA-lipid nanoparticles that could turn off the TTR gene to treat the liver which would replace the need for a liver transplant. In 2018, the first siRNA lipid nanoparticle was approved by the FDA.

For a detailed discussion of Anderson’s work on gene suppression with siRNA, gene expression with mRNA, permanent genetic editing using the CRISPR/Cas9 system, and on creating a cellular factory that can create drugs on demand, watch Anderson’s presentation online, available through December 31st.


Symposium X: Frontiers of Materials Research

F18_building_an_inclusive_ortiz_photoChristine Ortiz, Massachusetts Institute of Technology and Station1
Socially-Directed Science and Technology

MIT Professor and Co-founder of a non-profit higher education institution called Station1 based in Lawrence, Massachusetts, Christine Ortiz is leading the development of a new model of frontier learning and research—socially-directed science and technology. This exciting initiative, launched in collaboration with Co-founder and historian of science and technology also at MIT, Dr. Ellan Spero, is based upon a foundation of inclusion and equity; this model integrates science, technology, engineering, and math (STEM) with humanistic fields at a granular level in order to interrogate, understand, and shape technologically-driven societal impact towards more equitable, ethical, and sustainable outcomes.

Station1 delivers transformative education, research, and innovation programs and leads higher education systems change initiatives. The Station1 Frontiers Fellowship is a prestigious, fully-funded ten-week summer experience for undergraduate students that involves socially-directed science and technology education, research, and innovation. Unique in the nation and the world, the SFF includes an exciting research internship in emerging areas of science and technology, a cross-interdisciplinary shared curriculum on socially-directed science and technology, and personal and professional advancement activities. Approximately all of the Station1 Fellows alumni are from low income backgrounds, minoritized groups, and/or first generation to attend college.

To describe these concepts in her presentation, Ortiz posed the question, “How can we re-think the fundamental process of research that have enabled environmental and social inequities?” The field of materials science and engineering has contributed enormous benefits to society in, for example, medicine and healthcare, computation, transportation, infrastructure, and energy and, yet, has also been deeply entangled with social inequities and injustice. Examples discussed included materials, the Anthropocene, and environmental injustice focused on Louisiana’s Mississippi River, materials, racial and social inequity, and disparate risks to fire, shipbreaking, global interconnectedness, and social life cycle assessment.

At Station1, the work of the students does not take place on a college campus separate from the social inequities they’re entangling in their research but rather in a post-industrial mill town (Lawrence) where they are doing primary research on the infrastructure. Ortiz said, “We have students look at all kinds of materials and infrastructure outside in Lawrence and think about the embedded social structure to those technological systems that are still there today.”

The well-known tetrahedron of structure-properties-performance-synthesis & processing now embeds “society” in the center. Part of this approach is to reformulate research questions. “We have students actually look at literature scholarship from both the science and engineering field and humanistic field and put them into conversation with each other,” said Ortiz, “and think about ‘how can we leverage the best of both of these?’”

At MIT, Ortiz co-leads two educational projects called “Materials, Societal Impact, and Social Innovation,” and “The Social Life of Materials: Past.Present.Future” where students research the broader social context of historical and emerging materials technologies. The purpose of this educational approach is to prepare students to engage in scientific research and engineering in a way that fosters a more equitable and sustainable future.


Symposium X: Frontiers of Materials Research

Anke-weidenkaffAnke Weidenkaff, Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS

Efficient Recycling and Regeneration of E-Mobility Components and Materials

While the digital world has enabled virtual conferences such as this one—enabling the sharing of research results and networking among scientists during a pandemic—“digitalization” also comes with problems that affect the environment.

Anke Weidenkaff, executive director of the Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS in Germany, laid out the problems and possible solutions for sustainable technology and the role of materials.

Digitalization, she said, decreases the lifetime of devices. For example, when the circuit board now found in appliances such as a washing machine breaks, the whole machine is broken and now removed to the trash. Also, devices such as cell phones become quickly out-of-date, thus adding more products to the e-waste pile. In the future, Weidenkaff said, our cars and houses will be completely digitalized and quickly outdated, which puts the problem on a very different scale than small devices such as a cell phone.

Digitalization also leads to dissipation of strategic metals, which will have consequences for energy conversion processes, for example in electronic vehicles, or “e-mobility.” “We have to find solutions to recover strategic metals as soon as possible and also to design products so this dissipation will not take place in the future,” she said.

To achieve a zero-waste society, the current recycling paradigm—for example, for Li batteries—is inefficient because it creates more waste. “One possibility,” Weidenkaff said, “is to regenerate or self-heal the material, or to develop smart materials which can be converted without the deposition of waste.” At Fraunhofer IWKS, two approaches are being studied. In one approach, parts are automatically sorted with the help of sensors and separation technologies. “We are using artificial intelligence to increase the sorting procedure,” Weidenkaff said. The other approach involves electro-hydraulic fragmentation. Components made from recycled materials will then lead to the production of “green” products that will prevent resource problems in the future. More information can be found at the Fraunhofer IWKS website.

Weidenkaff also detailed the materials challenges involved with the recycling of high-performance permanent magnets which are predominant in electronic devices, and the materials challenges for achieving a hydrogen economy. To combat climate change, researchers need to develop a new way of thinking. For example, to substitute critical metals in magnets, researchers need to embark on a holistic evaluation of what criteria is needed from a material. They need to consider the material from an ecological, economics, supply availability, efficiency, durability, programmability, and multifunctionality approach. A new criteria, Weidenkaff said, would be a material that can be decomposed rapidly and reused elsewhere but at the same time is stable for its current use in a product.

“Smart materials can become very sustainable if they know what to do,” she said, “if you can tell them to ‘decompose yourself.’”


Symposium X: Frontiers of Materials Research

Vijay-narayananVijay Narayanan, IBM T.J. Watson Research Center
The Golden Age of Materials Innovations—From High-κ/Metal Gate to AI Hardware

In his early days at IBM, Vijay Narayanan introduced new materials at the nanoscale to incorporate into the core of the transistor in order to enable computers to work rapidly at low power. With the advent of deep learning-based artificial intelligence algorithms, materials innovation is required again. Currently, the research community is working under the idea that artificial neural networks can be mapped to arrays of non-volatile memory (NVM) elements. The NVM elements being evaluated as resistive processing units are falling short. Narayanan says innovation and collaboration across academia and industry is necessary to overcome this obstacle.

Complementary metal oxide semiconductor (CMOS) chips have reached the third generation in development in which fin field-effect transistor (finFETs) are fabricated through extreme ultraviolet lithography (EUV). The next step in the semiconductor technology roadmap is scaling down to 5 nm node and beyond through R&D in nanosheet device architectures.

For the next phase in semiconductor R&D, Narayanan said, “Materials scientists have had the opportunity to now impact a totally new era of AI compute.” In his talk, Narayanan concentrated on analog AI, “which is the concept of using nonvolatile memory elements crossbar arrays for deep learning acceleration.”

Deep learning has become essential because the amount of data available has increased exponentially, Narayanan said. Furthermore, with the deep learning explosion, in 2014 to 2015, accuracies in image recognition are better than what humans can do, and likewise with speech recognition. “This can be a significant benefit for the entire AI computer ecosystem,” Narayanan said. And now, due to machine learning, new technology and new paradigms are needed to absorb the emerging workloads.

Materials innovation comes into play in regards to new architectures for AI to help “consume the workloads and help map deep learning networks into something that can be energy efficient,” Narayanan said. It will be critical for materials researchers to collaborate with algorithmic teams early on in the R&D of AI hardware.

Narayanan’s presentation will be available online through December 31, 2020.


Symposium X: Frontiers of Materials Research

Symposium X Alessandra Lanzara_800x800Alessandra Lanzara, University of California, Berkeley, and Lawrence Berkeley National Laboratory

Engineering Two-Dimensional Heterostructures with a Twist 

Written by Arthur L. Robinson

The past few years have seen exciting new opportunities emerging from simply stacking and/or twisting together atom-thick layers of the same or different materials. The lattice mismatch or rotational misalignment introduced by such stacking gives rise to long-range Moiré patterns that lead to modification of the electronic band structure, which in turn gives rise to the appearance of unexpected properties, such as Mott-like behavior and superconductivity, even in weakly interacting systems such as graphene.

In her Thursday Symposium X presentation, Alessandra Lanzara of the University of California, Berkeley, and the Lawrence Berkeley National Laboratory described recent investigations by her group on twisted and strained graphene and transition metal dichalcogenide (TMD) heterostructures as a function of twisting angle and gating. Using angle-resolved photoemission spectroscopy, the group studied the effect of such misalignments on the electronic structure of these materials, yielding insight on the key parameters that lead to the onset of strong correlation and novel behavior in these materials.

Lanzara opened her talk by introducing the importance of topology as an essential theoretical tool in understanding the properties of materials. Until recently, thinking about transitions in crystalline solids has been based on order parameters related to symmetry breaking and correlations. Topology has now joined these as an organizing principle of matter. In general, topological properties are those that are preserved under continuous deformation. For example, in a topological insulator there is no sharp phase transition, but the insulator property is preserved as the electronic band structure is continuously deformed.

Symposium X Alessandra Lanzara 2_800x800

With the addition of topology, said Lanzara, it is now possible to describe the various states of materials now on a single diagram with a correlation energy on one axis and the spin–orbit coupling on the other. Close to the origin, conventional metals and insulators are well described by band theory. As the correlations increase, Mott insulators come to the fore, whereas topological insulators and semimetals come to the fore when spin–orbit coupling increases. But the future may lie in the panoply of exotic behaviors like Weyl insulators that arise as both correlations and spin–orbit coupling grow.

“What new cooperative phenomena and particles will occur when you bring together correlation, spin orbit coupling, and topology?” Lanzara asked next. Taking a hint from physicist Richard Feynman’s famed questions about two-dimensional pages, the question became “What would the properties of materials be if we could really arrange the atoms the way we want them?” But how would one go about exploring this immense space? One way to arrange atoms is by means of heterostructures consisting of stacks of materials with different properties with relevant aspects being dimensionality, coupling to the lattice, order (spin, charge, orbitals, and Cooper pairs in superconductors), and electrostatic doping. Outcomes of building these structures include emergent phenomena at interfaces, such as ferromagnetism, superconductivity, and metal-to-insulator transitions.

From here Lanzara rapidly reviewed some considerations, such as electron screening, and methods for controlling the electronic structure in the context of searching for new phenomena. In particular, her group found that twisting the layers in the heterostructure provided a new level of band-structure control. In fact, when Lanzara was being introduced as the speaker for this Symposium X, the MC used the term twist-tronics.

After discussing engineering of topology and strong correlation, including local inversion-symmetry breaking in the heterostructure layers that gives rise to spin–orbit coupling, Lanzara turned toward the possibility of an even larger phase space for materials design, moving from periodic crystals with both long- and short-range order, to quasiperiodic crystals with order but are not periodic, to Floquet crystals that are periodic in time, and ending with amorphous materials with no long-range order but perhaps some short-range order. After asking if amorphous systems can be used for materials engineering, she reported some early results on the amorphous topological insulator Bi2Se3. One task was to find a replacement for the momentum quantum numbers (kx, ky, kz) in crystals. The group was thinking of an (average) bulk Hamiltonian as spherically symmetric in k-space, resulting in a wavefunction parameterized by k2 and the angles q and f in a spherical coordinate system.

Lanzara summed up her presentation by declaring that two-dimensional heterostructures constitute an incredible, highly tunable platform for exploring correlation, symmetry breaking, and topology. The electronic structure of two-dimensional van der Waals materials is extremely easy to modify, including effects such as symmetry breaking to induce gap opening and renormalization effects due to screening, and spin–orbit coupling and other many-body interactions. But questions still ripe for investigation include: Can we design new types of many-body topological properties and new particles? And what new phases can result from the interplay between them?

Symposium X—Frontiers of Materials Research features lectures aimed at a broad audience to provide meeting attendees with an overview of leading-edge topics.


Symposium X: Frontiers of Materials Research

IMG_9094_800x800Francesco Stellacci, École Polytechnique Fédérale de Lausanne

Using Materials Science Concepts to Design New Drugs

Written by Don Monroe

Materials scientists have contributed to innovations in delivery of drugs, but only rarely to the drugs themselves. Francesco Stellacci described the efforts of his group to develop drugs against viruses. Viral diseases kill millions of people each year, mostly in the developing world, and new viruses are continually evolving or crossing over from animal reservoirs.

Although the best remedy is vaccines, these are not available for many important viruses. Once a disease is established, Stellacci said, there are only two drugs available: the cocktail against HIV, and drugs for Hepatitis C. These antiviral drugs work by interfering with specific machinery inside the cell that the viruses exploit.

A second approach is directly destroying viruses before infection, but such virucidal agents are toxic. A third strategy is blocking viral attachment to cells with a virustatic compound, such as heparin, that coats the virus. This idea had been explored in an HIV-blocking cream, but in a clinical trial it actually increased the rate of infection by concentrating viruses and releasing them into the bloodstream.

For Stellacci the key thermodynamic problem is that binding is reversible when the concentrations decrease. His inspiration was to build on binding by irreversibly opening up the virus. “We can always take a reversible process and build a cascade of events that make it irreversible,” he said, just as reversible electrochemistry becomes irreversible during corrosion.

The ligands through which viruses attach to cells vary widely, but among viral families there are a few that are highly conserved. These “attachment ligands” point to cell surface components that also rarely mutate, such as sialic acids (bound by influenza and others) and sulfonic-acid–bearing heparan sulfate proteoglycans (bound by dengue, Ebola, herpes simplex, HIV, HPV, and others). Targeting these ligands could allow broad-spectrum antiviral drugs.

IMG_9154_800x800

Stellacci’s idea was to introduce multiple targets for attachment-ligand binding (initially sulfonic acid groups), each tethered by a large, flexible, hydrophobic chain to a common platform (initially a gold nanoparticle). The enforced proximity of the hydrophobic chains will create local pressure that could induce the virus to break up.

Experiments confirmed that this structure killed viruses in vitro at nanomolar concentrations, which is sensitive enough to be interesting but could have been achieved with heparin. To demonstrate irreversibility, Stallacci’s team developed an assay by killing 99% of the viruses and then highly diluting the mixture to see if the inhibition persisted. This assay proved that the effect was indeed irreversible for a broad spectrum of viruses.

As expected, the effect became reversible when the researchers replaced the hydrophobic chain with ethylene glycol or replaced the sulfonic acid group with a carboxylic acid group.

The researchers went on to demonstrate effectiveness against HSV-2 in human vaginal tissue ex vivo. They also successfully treated mice with respiratory RSV infection in vivo using an intranasal spray.

Importantly, Stellaci’s team showed that the initial gold-nanoparticle anchor was not necessary, achieving similar effectiveness with a cyclodextrin acting as a rigid backbone for the sulfonated chains. This permits larger scale production, which let the researchers demonstrate that treatment releases the viral DNA payload, confirming the breakup of the viruses.

Although the results so far have been positive and support further experiments, Stellacci cautioned that there is still much work to be done, for example to deliver the necessary local and global concentrations in large animals. But he stressed that even if this particular approach falls short, the work demonstrates the effectiveness of using materials-science principles in drug design. Stellacci also urged researchers not to limit their attention to the problems of rich populations.

Symposium X—Frontiers of Materials Research features lectures aimed at a broad audience to provide meeting attendees with an overview of leading-edge topics.

 


Symposium X: Frontiers of Materials Research

IMG_8698_800x800Evelyn N. Wang, Massachusetts Institute of Technology

Nanoengineered Materials for Advanced Energy and Water Technologies 

Written by Arthur L. Robinson

Evelyn Wang, head of MIT’s Mechanical Engineering Department, opened her Tuesday Symposium X presentation by stating that the goal for her research programs was to take advantage of nanoengineered materials and their new functionalities to realize exciting, untapped potentials for advancing energy and water technologies. The emphasis of her talk was more on using nanoengineered materials to solve problems than on methods for developing new materials. In particular, she provided examples of how her groups were leveraging nanoscale manipulation capabilities to develop devices for advanced thermal management, solar thermal energy conversion, and water harvesting.

For context, Wang reviewed the current breakdown of US energy consumption (97.4 quadrillion BTU) by production technology, showing that renewable-energy technologies accounted for only 10% of the total. Energy for residential and commercial buildings, transportation, and industry is dominated by fossil fuels (petroleum, natural gas, and coal), with the consequence that the resulting greenhouse-gas emissions are driving the dire climate-warming future that we will inherit if nothing changes. In working to mitigate climate change, Wang’s goal is to do so while retaining our current, comfortable daily lives as much as possible.

Of the various renewable-energy technologies, solar energy remains underutilized at about 6% of the overall 10% renewable share. Wang’s group aims to develop more efficient and lower-cost solutions to make solar energy utilization more viable. They chose to focus on solar thermal rather than photovoltaic power in part because solar thermal is currently more amenable to low-cost energy storage and thus make solar thermal a reliable, around-the-clock technology. The idea is to harness solar energy in the form of heat from a field of solar collectors to generate electricity via a steam cycle. At present it is still a low-efficiency (overall solar-to-electricity conversion efficiency of 10-15%, and high-cost technology. Wang’s group looked at two ways to boost the efficiency.

First, they identified a possibility to increase the efficiency of the electricity-generation side by decreasing the steam-condenser temperature and turbine backpressure. It turns out that condensation heat transfer is hampered by a liquid film, whereas droplet-covered surfaces are more efficient, but droplets tend to wet the surface, resulting in a spread-out film in the end. Wang discussed her group’s recent work that takes advantage of novel surface designs to control and manipulate wettability and liquid-vapor phase-change processes. They demonstrated high-flux evaporation from ultrathin nanoporous membranes and nanostructured “non-wicking” surfaces that can repel liquids even during condensation, preventing wetting of the surface. The pores are the key, tending to support the droplets rather than letting them spread out.

IMG_8732_800x800
Second, the group looked at how nanoengineered materials could be used to increase the efficiency on the solar-collector side. Specifically, they worked on optically transparent, thermally insulating silica aerogel solar receivers to enhance the solar-collection efficiency over that of the traditional trough-shaped mirror arrays. The basic high-efficiency, air-stable device comprises a sandwich of protective glass covered with the aerogel on top of which a painted black absorbed layer interfaces with an array of fluid-filled pipes covered by black absorber layers. Solar radiation incident on an array of linear Fresnel reflectors reflects the light to the aerogel device, where it heats the fluid in the pipes. The keys are the high transparency and the low thermal conductivity of the group’s specially developed aerogel, which allows the sunlight to pass through the aerogel and heat the fluid in the pipes without heat losses through the aerogel.

Related work with aerogels included double-pane windows with aerogel between the panes. Here the key was to find a solution to the haze that can degrade the view through the pane. With the MIT aerogel, insulation performance nearly equaled that of triple-pane windows at a cost closer to that of conventional double-pane windows. A second application was the use of polyethylene aerogels in radiative cooling devices. Here, the key is an overlap between the blackbody emission spectrum and an infrared atmospheric window to allow radiative cooling on earth. Daytime cooling to below the ambient temperature requires optically selective surfaces or geometries to achieve high solar reflectivity and high infrared emissivity. High solar absorption and poor thermal insulation are challenges to cooling. A porous, low-density aerogel made of polyethylene was a good fit, demonstrated by successful tests at a site in the arid Atacama Desert region of Chile.

Speaking of arid climates, Wang finished up with a description of water harvesting powered by natural sunlight. In the most arid regions of the earth, water scarcity is so extreme that it is present all year with no relief. Overall water scarcity affects 20% of the global population. Water in the air is a resource equivalent to 14% of freshwater in the lakes of the earth (13,000 trillion liters). To address water-scarcity challenges in arid climates, Wang’s approach to the problem was to look at a water-harvesting device that leverages the unique properties of metal–organic frameworks (MOFs). Dewing is one existing water-harvesting technology, but it is only suited for high relative humidity conditions and thus not appropriate for arid environments. Working with researchers at the University of California-Berkeley, the group devised a water-harvesting device based on porous MOF in a reflective enclosure that adsorbs water molecules at night and releases it as the sun heats it during the day. The water vapor then condenses and is collected. Depending on the MOF, the device is effective at relative humidities below 20% in tests in Tempe, Arizona.

In summing up, Wang pointed to scale-up of materials to larger quantities, cost reduction, robustness over a long life, and improved performance as significant challenges to transferring the technology to the commercial world.

Symposium X—Frontiers of Materials Research features lectures aimed at a broad audience to provide meeting attendees with an overview of leading-edge topics.


Symposium X: Frontiers of Materials Research

IMG_8471_800x800Brian Litt, University of Pennsylvania

Ghost in the Machine—Translating New Technologies into Next-Generation Neurodevices

Written by Don Monroe

As a medical doctor as well as a professor of neurology, neurosurgery, and bioengineering, Brian Litt was well positioned in his Symposium X talk to share the phenomenal impact that neural interfaces are having on patients’ lives. These devices owe much of their success to the brain’s ability to adapt to their still-primitive signals, he stressed. “It’s because of neuroplasticity patients that can actually use this stuff.”

Litt illustrated the disappointingly low resolution available from retinal implants, and the distorted sounds available from a few frequency bands from a cochlear implant. He also briefly described advances in speech synthesis and motor control through human-machine interfaces. In addition, he listed a host of diseases that might be treated through manipulation of peripheral nerves. “While these are amazing accomplishments,” he said, “there’s a lot more to be done.”

Litt encouraged materials scientists to contribute their expertise to these highly interdisciplinary problems: “We need both incremental and disruptive innovation.” He noted the importance an institutional framework that includes animal models and an infrastructure for ultimately translating innovations from the bench to the clinic, as well as funding for commercialization. “These don’t all have to be at your institution,” he stressed, although he noted that “at Penn, we have most of this together.”

Technical challenges include smaller sensors with higher resolution and exchange of high-bandwidth signals between embedded devices and the outside world. The devices themselves can create tissue injury and degrade in the biological environment. In particular, biocompatibility requires mechanically similar materials to reduce damage during inevitable tissue movements.

All devices that monitor or stimulate neurons face many common issues, but there are additional challenges for implants in the brain, such as those Litt and his collaborators have explored for epilepsy. Litt chronicled one patient’s often unsatisfying history, which included previous crude procedures and failures to identify the precise brain region that initiated seizures. Litt and his colleagues eventually located and laser-ablated the correct region and eliminated daytime seizures, but limitations of imaging, tissue damage, and poor understanding of the disease neurophysiology remain frustrating.

For analysis, Litt envisions combining onboard processing with transmission of salient data to the cloud for more intensive processing. There is also room to improve the algorithms, as illustrated by a recent USD$25K competition to detect or predict seizures from neural data, which significantly improved on previous methodologies.

IMG_8512_800x800

Litt listed hopes for future brain technology, including “native delivery” that avoids invasive surgical procedures. Flexible targeting of denser electrodes, or even moving electrodes, could help zoom in on areas of interest. He also mentioned several promising ideas, many discussed at previous MRS meetings. These include electrodes that are flexible or can be injected into the brain, although he stressed the importance of probing the deep folds of the brain and not just its surface. Another proposal would exploit the blood vessels to deliver injected devices that can later be mapped.

There are many other potential approaches, such as “living electrodes,” magnetically activated liposomes, and microfluidically controlled electrodes, magnetothermal delivery, and ultrasonically activated “neural dust.” Optogenetic manipulation of brain circuitry is “absolutely possible,” Litt said, although the path to human use remains undefined. Ultrasound can also directly perform neural modulation or can be used to direct light for optogenetics.

“There’s tremendous opportunity,” Litt said. “What we’re doing is impressive, but still crude. Even this is life-changing.”

Symposium X—Frontiers of Materials Research features lectures aimed at a broad audience to provide meeting attendees with an overview of leading-edge topics.