Tag Archives: Paul Alivisatos

2024 Kavli Prize Laureates: in the fields of astrophysics, nanoscience and neuroscience

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The Kavli Prize has yet to acquire the lustre of a Nobel Prize (first awarded in 1901 as per its Wikipedia entry). By comparison the Kavli Prize is relatively new (established in 2005 as per its Wikipedia entry) but it appears to be achieving big deal status in the US.

This year’s crop of prize winners was listed in a June 12, 2024 Kavli Foundation news release on EurekAlert,

Eight scientists from three countries are honored for their research that has broadened our understanding of the big, the small and the complex.

June 12, 2024 (Oslo, Norway) — The Norwegian Academy of Science and Letters today announced the 2024 Kavli Prize Laureates in the fields of astrophysics, nanoscience and neuroscience. Eight scientists from three countries are honored for their research that has broadened our understanding of the big, the small and the complex. The laureates in each field will share $1 million USD. 

The 2024 Kavli Prizes recognize groundbreaking science for the discovery and characterization of extra-solar planets and their atmospheres; foundational research integrating synthetic nanoscale materials for biomedical use; and the localization of areas in the brain specialized for face recognition and processing.  

The 2024 Kavli Prize Laureates are:  

  • Kavli Prize in Astrophysics: David Charbonneau (Canada/USA) and Sara Seager (Canada/USA) 
  • Kavli Prize in Nanoscience: Robert S. Langer (USA), Armand Paul Alivisatos (USA) and Chad A. Mirkin (USA) 
  • Kavli Prize in Neuroscience: Nancy Kanwisher (USA), Winrich Freiwald (Germany), and Doris Tsao (USA) 

“The Kavli Prize 2024 honors outstanding researchers doing fundamental science that moves the world forward. They are exploring planets outside our solar system; they have broadened the scientific field of nanoscience towards biomedicine; and they are adding to our understanding of the neurological basis of face recognition,” said Lise Øvreås, president at The Norwegian Academy of Science and Letters.  

Astrophysics: Searching for life beyond Earth  

The 2024 Kavli Prize in Astrophysics honors Sara Seager and David Charbonneau for discoveries of exoplanets and the characterization of their atmospheres. They pioneered methods for the detection of atomic species in planetary atmospheres and the measurement of their thermal infrared emission, setting the stage for finding the molecular fingerprints of atmospheres around both giant and rocky planets. Their contributions have been key to the enormous progress seen in the last 20 years in the exploration of myriad exo-planets.  

“Humans have always looked towards the stars for discoveries. The pivotal research conducted by Seager and Charbonneau has been an important first step towards finding new planets and strong evidence of life elsewhere in the universe,” remarked Viggo Hansteen, Chair of the Astrophysics Committee.  

David Charbonneau led the team that used the transit method to discover a giant exoplanet (HD 209458b). He pioneered the application of space-based observatories to perform the first studies of the atmosphere of giant extrasolar planets. This new method measures the tiny amount of light blocked by such a planet as it passes in front of its host star. Charbonneau has also used the transit method to study exoplanetary atmospheres, measuring molecular spectra using both filtered starlight and infrared emission from the planets themselves. He demonstrated these two approaches with observations from the Hubble Space Telescope in 2002 and the Spitzer Space Telescope three years later.  

Sara Seager pioneered the theoretical study of planetary atmospheres and predicted the presence of atomic and molecular species detectable by transit spectroscopy, most notably the alkali gases. She predicted how transits could be used to measure atomic and molecular characteristics in exoplanetary atmospheres, which is crucial for identifying biomarkers – signs of life. Seager made outstanding contributions to the understanding of planets with masses below that of Neptune. She also carried out extensive research on starshades – enormous petal-like structures designed to shield space observatories from the glare of a faraway Sun-like star – and was among the first to recognize their importance in detecting and characterizing the faint light from any Earth-like planet orbiting the star. 

Nanoscience: Integrating nanomaterials for biomedical advances 

The 2024 Kavli Prize in Nanoscience honors Robert S. Langer, Armand Paul Alivisatos and Chad A. Mirkin who each revolutionized the field of nanomedicine by demonstrating how engineering nanoscale materials can advance biomedical research and application. Their discoveries contributed foundationally to the development of therapeutics, vaccines, bioimaging and diagnostics.   

“The three scientists, Langer, Alivisatos and Mirkin, have broadened the scientific field of nanoscience, building from fundamental research. By scientific curiosity they have become inventors for the future of nanoscience and biomedicine,” stated Bodil Holst, Chair of the Nanoscience Committee.  

Robert S. Langer was the first to develop nano-engineered materials that enabled the controlled release, or regular flow, of drug molecules. This capability has had an immense impact for the treatment of a range of diseases, such as aggressive brain cancer, prostate cancer and schizophrenia. His work also showed that tiny particles, containing protein antigens, can be used in vaccination, and was instrumental in the development of the delivery of mRNA vaccines. 

Armand Paul Alivisatos demonstrated that semiconductor nanocrystals, or quantum dots (nanoparticles that possess bright, size-dependent light-emitting properties), can be used as multicolor probes in bioimaging. Essential to this achievement was the synthesis of biocompatible nanocrystals. Semiconductor nanocrystals became the basis for the widely used research and diagnostic tools such as live cell tracking, labelling and in vivo imaging. 

Chad A. Mirkin engineered spherical nucleic acids (SNA) using a gold nanoparticle as the core, and a cloud of radially distributed DNA or RNA strands as the shell. He was then able to show how SNAs can be combined to create larger structures and how they can be used in biodiagnostics. His discovery led to the development of fast, automated point-of-care medical diagnostic systems.  

Neuroscience: Understanding recognition of faces 

The 2024 Kavli Prize in Neuroscience honors Nancy Kanwisher, Doris Tsao and Winrich Freiwald for the discovery of a specialized system within the brain to recognize faces. Their discoveries have provided basic principles of neural organization and made the starting point for further research on how the processing of visual information is integrated with other cognitive functions.  

“Kanwisher, Freiwald and Tsao together discovered a localized and specialized neocortical system for face recognition. Their outstanding research will ultimately further our understanding of recognition not only of faces, but objects and scenes,” commented Kristine Walhovd, Chair of the Neuroscience Committee.  

Nancy Kanwisher was the first to prove that a specific area in the human neocortex is dedicated to recognizing faces, now called the fusiform face area. Using functional magnetic resonance imaging (fMRI) she found individual differences in the location of this area and devised an analysis technique to effectively localize specialized functional regions in the brain. This technique is now widely used and applied to domains beyond the face recognition system.  

Elaborating on Kanwisher’s findings, Winrich Freiwald and Doris Tsao studied macaques and mapped out six distinct brain regions, known as the face patch system, including these regions’ functional specialization and how they are connected. By recording the activity of individual brain cells, they revealed how cells in some face patches specialize in faces with particular views.  

Tsao proceeded to identify how the face patches work together to identify a face, through a specific code that enables single cells to identify faces by assembling information of facial features. For example, some cells respond to the presence of hair, others to the distance between the eyes. 

Freiwald uncovered that a separate brain region, called the temporal pole, accelerates our recognition of familiar faces, and that some cells are selectively responsive to familiar faces. 

…

There’s a video of the official 2024 Kavli Prize announcement which despite the Kavli Foundation being headquartered in California, US, was held (as noted in the news release) at the Norwegian Academy of Science and Letters where the organization’s president, Lise Øvreås, revealed the 2024 Kavli Prize laureates..(I’ll get back to that choice of location.)

The 2024 Kavli Prize in Nanoscience

There are many posts here featuring work from Robert S. Langer (or Robert Langer), Armand Paul Alivisatos (or Paul Alivisatos or A. Paul Alivisatos) and Chad A. Mirkin (or Chad Mirkin).

Northwestern University (Chicago, Illinois) issued a June 12, 2024 news release (also received via email) by Maria Paul that provides a few more details about the nanoscience winners (main focus: Chad Mirkin), the prize, and the Kavli Foundation. Note: A link has been removed,

Northwestern University nanoscientist Chad Mirkin has been awarded The 2024 Kavli Prize in Nanoscience by The Norwegian Academy of Science and Letters. Mirkin is the first Northwestern scientist to receive the prestigious award.

Mirkin is recognized for his discovery of spherical nucleic acids (SNAs), nanostructures comprised of a nanoparticle core and a shell of radially distributed DNA or RNA strands. These globular forms of nucleic acids have become the cornerstones of the burgeoning fields of nanomedicine and colloidal crystal engineering with DNA. They allow scientists to construct new forms of matter using particle “atoms” as the basic building blocks and DNA “bonds” as particle interconnects, and they are the basis for powerful tools that allow researchers and clinicians to track and treat disease in new ways. In particular, SNAs have led to the development of fast, automated point-of-care medical diagnostic systems and new experimental drugs for treating many forms of cancer, neurological disorders, and diseases of the skin.

Mirkin is one of three laureates in nanoscience recognized by The Norwegian Academy for revolutionizing the field of nanomedicine by demonstrating how engineering nanoscale structures can advance biomedical research and application. The other two are Robert Langer of the Massachusetts Institute of Technology and Paul Alivisatos of the University of Chicago [emphasis mine]. The scientists’ discoveries “contributed foundationally to the development of therapeutics, vaccines, bioimaging and diagnostics,” The Norwegian Academy said in a release. They will share the $1 million award.

“When I first found out I won The Kavli Prize, there was both excitement but also relief, because I consider Northwestern to be the ultimate center for nanotechnology research,” Mirkin said. “To be recognized with this award, along with my incredible co-awardees, was great validation of what we’ve been trying to do at Northwestern. While I’m proud of what we’ve accomplished, the best is yet to come.”

The laureates will be awarded the prize on Sept. 3 during a ceremony in Oslo, Norway, presided over the by The Royal Family. The Kavli Prizes thus far have honored 65 scientists from 13 countries. Ten laureates received the Nobel Prize after receiving The Kavli Prize. [emphasis mine]

“I am thrilled for Chad, for the International Institute for Nanotechnology and for Northwestern,” Northwestern President Michael Schill said. “Chad has earned this prestigious and influential award in a pathbreaking area of science that is aligned with two of the University’s key priorities — to lead in decarbonization, renewable energy and sustainability, and innovating in the biosciences to help prolong lives and make the world a healthier place.

“Through groundbreaking research and hard work, Chad and his team have made Northwestern a leading center for nanotechnology research and investment. The fact that he is sharing this award with President Alivisatos at U of C further emphasizes how the Chicago area has become an international hub for nano research.”

The vision for The Kavli Prize comes from Fred Kavli, a Norwegian-American entrepreneur and philanthropist [emphasis mine] who turned his lifelong fascination with science into a lasting legacy for recognizing scientific breakthroughs and supporting basic research.

Since the first awards in 2008, The Kavli Prize has recognized innovative scientific research — from the discovery of CRISPR-Cas9 to the detection of gravitational waves — transforming our understanding of the big, the small and the complex.

Mirkin’s discovery of SNAs has far-reaching implications for biology and medicine. SNAs, which have no known natural equivalents, interact uniquely with living systems compared to nucleic acids of other forms. Mirkin was the first to synthesize SNAs and elucidate the distinctive chemical and physical properties that underpin their use in transformative techniques and technologies in medicine and the life sciences. This work has led to the development of the first commercialized molecular medical diagnostic systems of the modern nanotechnology era, such as the Food and Drug Administration-cleared Verigene System, used in over half of the world’s top hospitals to detect diseases with high sensitivity and selectivity.

Illinois Gov. JB Pritzker praised Mirkin for his extraordinary contributions to the field of nanotechnology and how his innovations have helped find solutions to some of society’s biggest challenges.

“Academic institutions in Chicago and across Illinois have become the biggest drivers in nanoscience and technology over the last three decades,” Pritzker said. “Chad Mirkin and his Northwestern colleagues have made outstanding scientific discoveries that change how we view the world around us.”

In 1996, Mirkin created the first SNAs with DNA shells on gold nanoparticle cores. Over the years, he has developed numerous other types of SNAs with other shells and cores, including proteins, liposomes and FDA-approved materials, as well as core-less, hollow structures composed entirely of nucleic acids. These cores impart unique properties to the SNAs, such as optical and magnetic characteristics, while also serving as scaffolds to densely arrange the oligonucleotides, which participate in binding. This dense arrangement gives rise to the novel functional properties that differentiate SNAs from the natural linear and two-dimensional nucleic acids and make them particularly effective in interacting with certain biological structures within cells and tissues. SNAs, unlike conventional DNA and RNA, are naturally taken up by cells without the need for toxic, positively charged co-carriers, making them highly effective in RNA interference (RNAi), antisense gene regulation, and gene editing pathways.

Mirkin’s pioneering work on SNAs has also advanced the development of immunotherapeutics, structures capable of stimulating a patient’s immune response to fight both infectious diseases and certain forms of cancer. Using SNAs, Mirkin has pioneered the concept of rational vaccinology, where he demonstrated that the structure of a vaccine, rather than the components alone, is crucial for dictating its therapeutic effectiveness. This insight and these “structural nanomedicines” have opened new possibilities for developing curative treatments by rearranging known components into more effective structures at the nanoscale. Mirkin founded Flashpoint Therapeutics to commercialize these innovations, focusing on nucleic acid-based nanostructure cancer vaccines. Mirkin also invented the first SNA-based antiviral vaccine, using COVID-19 as a model. These SNAs, featuring the spike protein’s RBD subunit in the core, achieved a 100% survival rate in humanized mice challenged with the live virus. These structures and concepts for designing such vaccines are poised to move vaccine development beyond the current mRNA vaccines.

In addition, Mirkin invented dip-pen nanolithography, initially a technique for molecular writing with nanometer-scale precision that has evolved into a powerful platform for tip-based materials synthesis that, when combined with artificial intelligence, is revolutionizing how materials important for many sectors, especially clean energy, are discovered. Dip-pen nanolithography, which has spurred subsequent techniques that now use tens of millions of tiny tips to rapidly synthesize materials to be explored for such purposes, was recognized by National Geographic as one of the “top 100 scientific discoveries that changed the world.” These innovations are being commercialized by Mattiq, Inc., another venture-backed company Mirkin cofounded. Mirkin and his students also invented high-area rapid printing, an additive manufacturing technology, that is being commercialized by Azul 3D and being used to disrupt the microelectronics and optical lens industries.

Mirkin’s research has progressed SNA drugs through seven human clinical trials so far for treating various cancers, including glioblastoma multiforme and Merkel cell carcinoma. One SNA drug has shown remarkable potential in stimulating the immune system, proving effective in models of breast, colorectal and bladder cancers, lymphoma and melanoma. This drug has achieved complete tumor elimination in a subset of patients with Merkel cell carcinoma during Phase 1b/2 clinical trials, earning FDA fast-track and orphan drug status. It was recently licensed to Bluejay Therapeutics to treat hepatitis.

In 2000, Mirkin founded the International Institute for Nanotechnology (IIN) at Northwestern University, which he also directs. Research at the IIN has led to over 2,000 new commercial products sold globally and the creation of more than 40 startup companies. The IIN has collectively brought together over $1.2 billion to support research, education and infrastructure at Northwestern since its inception.

Mirkin is the George B. Rathmann Professor of Chemistry and a professor of medicine, chemical and biological engineering, biomedical engineering, and materials science and engineering at Northwestern. He is among an elite group of scientists elected to all three branches of the U.S. National Academies — the National Academy of Sciences, the National Academy of Engineering and the National Academy of Medicine. He is a member of the American Academy of Arts and Sciences. Mirkin served on President Obama’s Council of Advisors on Science and Technology for eight years.

Congratulations to all of the winners in all of the categories!

As for the Norway announcement, it makes a bit of sense given that Fred Kavli was a Norwegian American. However, it’s a little hard to avoid the suspicion that there might be some regional and prize rivalry between Norway with its Kavli and Sweden its Nobel..

Philosophy and science in Tokyo, Japan from Dec. 1-2, 2022

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I have not seen a more timely and à propos overview for a meeting/conference/congress that this one for Tokyo Forum 2022 (hosted by the University of Tokyo and South Korea’s Chey Institute for Advanced Studies),

“Dialogue between Philosophy and Science: In a World Facing War, Pandemic, and Climate Change”

In the face of war, a pandemic, and climate change, we cannot repeat the history of the last century, in which our ancestors headed down the road to division, global conflict, and environmental destruction.

How can we live more fully and how do we find a new common understanding about what our society should be? Tokyo Forum 2022 will tackle these questions through a series of in-depth dialogues between philosophy and science. The dialogues will weave together the latest findings and deep contemplation, and explore paths that could lead us to viable answers and solutions.

Philosophy of the 21st century must contribute to the construction of a new universality based on locality and diversity. It should be a universality that is open to co-existing with other non-human elements, such as ecosystems and nature, while severely criticizing the understanding of history that unreflectively identifies anthropocentrism with universality.

Science in the 21st century also needs to dispense with its overarching aura of supremacy and lack of self-criticism. There is a need for scientists to make efforts to demarcate their own limits. This also means reexamining what ethics means for science.

Tokyo Forum 2022 will offer multifaceted dialogues between philosophers, scientists, and scholars from various fields of study on the state and humanity in the 21st century, with a view to imagining and proposing a vision of the society we need.

Here are some details about the hybrid event from a November 4, 2022 University of Tokyo press release on EurekAlert,

The University of Tokyo and South Korea’s Chey Institute for Advanced Studies will host Tokyo Forum 2022 from Dec. 1-2, 2022. Under this year’s theme “Dialogue between Philosophy and Science,” the annual symposium will bring together philosophers, scientists and scholars in various fields from around the world for multifaceted dialogues on humanity and the state in the 21st century, while envisioning the society we need.

The event is free and open to the public, and will be held both on site at Yasuda Auditorium of the University of Tokyo and online via livestream. [emphases mine]

Keynote speakers lined up for the first day of the two-day symposium are former U.N. Secretary-General Ban Ki-moon, University of Chicago President Paul Alivisatos and Mariko Hasegawa, president of the Graduate University for Advanced Studies in Japan.

Other featured speakers on the event’s opening day include renowned modern thinker and author Professor Markus Gabriel of the University of Bonn, and physicist Hirosi Ooguri, director of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo and professor at the California Institute of Technology, who are scheduled to participate in the high-level discussion on the dialogue between philosophy and science.

Columbia University Professor Jeffrey Sachs will take part in a panel discussion, also on Day 1, on tackling global environmental issues with stewardship of the global commons — the stable and resilient Earth system that sustains our lives — as a global common value.

The four panel discussions slated for Day 2 will cover the role of world philosophy in addressing the problems of a globalized world; transformative change for a sustainable future by understanding the diverse values of nature and its contributions to people; the current and future impacts of autonomous robots on society; and finding collective solutions and universal values to pursue equitable and sustainable futures for humanity by looking at interconnections among various fields of inquiry.

Opening remarks will be delivered by University of Tokyo President Teruo Fujii and South Korea’s SK Group Chairman Chey Tae-won, on Day 1. Fujii and Chey Institute President Park In-kook will make closing remarks following the wrap-up session on the second and final day.

Tokyo Forum with its overarching theme “Shaping the Future” is held annually since 2019 to stimulate discussions on finding the best ideas for shaping the world and humanity in the face of complex situations where the conventional wisdom can no longer provide answers.

…

For more information about the program and speakers of Tokyo Forum 2022, visit the event website and social media accounts:

Website: https://www.tokyoforum.tc.u-tokyo.ac.jp/en/index.html

Twitter: https://twitter.com/UTokyo_forum

Facebook: https://www.facebook.com/UTokyo.tokyo.forum/

…

To register, fill out the registration form on the Tokyo Forum 2022 website (registration is free but required [emphasis mine] to attend the event): https://www.tokyo-forum-form.com/apply/audiences/en

I’m not sure how they are handling languages. I’m guessing that people are speaking in the language they choose and translations (subtitles or dubbing) are available. For anyone who may have difficulty attending due to timezone issues, there are archives for previous Tokyo Forums. Presumably 2022 will be added at some point in the future.

SINGLE (3D Structure Identification of Nanoparticles by Graphene Liquid Cell Electron Microscopy) and the 3D structures of two individual platinum nanoparticles in solution

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It seems to me there’s been an explosion of new imaging techniques lately. This one from the Lawrence Berkelely National Laboratory is all about imaging colloidal nanoparticles (nanoparticles in solution), from a July 20, 2015 news item on Azonano,

Just as proteins are one of the basic building blocks of biology, nanoparticles can serve as the basic building blocks for next generation materials. In keeping with this parallel between biology and nanotechnology, a proven technique for determining the three dimensional structures of individual proteins has been adapted to determine the 3D structures of individual nanoparticles in solution.

A multi-institutional team of researchers led by the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab), has developed a new technique called “SINGLE” that provides the first atomic-scale images of colloidal nanoparticles. SINGLE, which stands for 3D Structure Identification of Nanoparticles by Graphene Liquid Cell Electron Microscopy, has been used to separately reconstruct the 3D structures of two individual platinum nanoparticles in solution.

A July 16, 2015 Berkeley Lab news release, which originated the news item, reveals more details about the reason for the research and the research itself,

“Understanding structural details of colloidal nanoparticles is required to bridge our knowledge about their synthesis, growth mechanisms, and physical properties to facilitate their application to renewable energy, catalysis and a great many other fields,” says Berkeley Lab director and renowned nanoscience authority Paul Alivisatos, who led this research. “Whereas most structural studies of colloidal nanoparticles are performed in a vacuum after crystal growth is complete, our SINGLE method allows us to determine their 3D structure in a solution, an important step to improving the design of nanoparticles for catalysis and energy research applications.”

Alivisatos, who also holds the Samsung Distinguished Chair in Nanoscience and Nanotechnology at the University of California Berkeley, and directs the Kavli Energy NanoScience Institute at Berkeley (Kavli ENSI), is the corresponding author of a paper detailing this research in the journal Science. The paper is titled “3D Structure of Individual Nanocrystals in Solution by Electron Microscopy.” The lead co-authors are Jungwon Park of Harvard University, Hans Elmlund of Australia’s Monash University, and Peter Ercius of Berkeley Lab. Other co-authors are Jong Min Yuk, David Limmer, Qian Chen, Kwanpyo Kim, Sang Hoon Han, David Weitz and Alex Zettl.

Colloidal nanoparticles are clusters of hundreds to thousands of atoms suspended in a solution whose collective chemical and physical properties are determined by the size and shape of the individual nanoparticles. Imaging techniques that are routinely used to analyze the 3D structure of individual crystals in a material can’t be applied to suspended nanomaterials because individual particles in a solution are not static. The functionality of proteins are also determined by their size and shape, and scientists who wanted to image 3D protein structures faced a similar problem. The protein imaging problem was solved by a technique called “single-particle cryo-electron microscopy,” in which tens of thousands of 2D transmission electron microscope (TEM) images of identical copies of an individual protein or protein complex frozen in random orientations are recorded then computationally combined into high-resolution 3D reconstructions. Alivisatos and his colleagues utilized this concept to create their SINGLE technique.

“In materials science, we cannot assume the nanoparticles in a solution are all identical so we needed to develop a hybrid approach for reconstructing the 3D structures of individual nanoparticles,” says co-lead author of the Science paper Peter Ercius, a staff scientist with the National Center for Electron Microscopy (NCEM) at the Molecular Foundry, a DOE Office of Science User Facility.

“SINGLE represents a combination of three technological advancements from TEM imaging in biological and materials science,” Ercius says. “These three advancements are the development of a graphene liquid cell that allows TEM imaging of nanoparticles rotating freely in solution, direct electron detectors that can produce movies with millisecond frame-to-frame time resolution of the rotating nanocrystals, and a theory for ab initio single particle 3D reconstruction.”

The graphene liquid cell (GLC) that helped make this study possible was also developed at Berkeley Lab under the leadership of Alivisatos and co-author Zettl, a physicist who also holds joint appointments with Berkeley Lab, UC Berkeley and Kavli ENSI. TEM imaging uses a beam of electrons rather than light for illumination and magnification but can only be used in a high vacuum because molecules in the air disrupt the electron beam. Since liquids evaporate in high vacuum, samples in solutions must be hermetically sealed in special solid containers – called cells – with a very thin viewing window before being imaged with TEM. In the past, liquid cells featured silicon-based viewing windows whose thickness limited resolution and perturbed the natural state of the sample materials. The GLC developed at Berkeley lab features a viewing window made from a graphene sheet that is only a single atom thick.

“The GLC provides us with an ultra-thin covering of our nanoparticles while maintaining liquid conditions in the TEM vacuum,” Ercius says. “Since the graphene surface of the GLC is inert, it does not adsorb or otherwise perturb the natural state of our nanoparticles.”

Working at NCEM’s TEAM I, the world’s most powerful electron microscope, Ercius, Alivisatos and their colleagues were able to image in situ the translational and rotational motions of individual nanoparticles of platinum that were less than two nanometers in diameter. Platinum nanoparticles were chosen because of their high electron scattering strength and because their detailed atomic structure is important for catalysis.

“Our earlier GLC studies of platinum nanocrystals showed that they grow by aggregation, resulting in complex structures that are not possible to determine by any previously developed method,” Ercius says. “Since SINGLE derives its 3D structures from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale.”

The next step for SINGLE is to recover a full 3D atomic resolution density map of colloidal nanoparticles using a more advanced camera installed on TEAM I that can provide 400 frames-per-second and better image quality.

“We plan to image defects in nanoparticles made from different materials, core shell particles, and also alloys made of two different atomic species,” Ercius says. [emphasis mine]

“Two different atomic species?”, they really are pushing that biology analogy.

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

3D structure of individual nanocrystals in solution by electron microscopy by Jungwon Park, Hans Elmlund, Peter Ercius, Jong Min Yuk, David T. Limme, Qian Chen, Kwanpyo Kim, Sang Hoon Han, David A. Weitz, A. Zettl, A. Paul Alivisatos. Science 17 July 2015: Vol. 349 no. 6245 pp. 290-295 DOI: 10.1126/science.aab1343

This paper is behind a paywall.

Graphene liquid cells and movies at the nanoscale

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Here’s an Oct. 3, 2013 news item on Azonano about transmission electron microscopy (TEM) and graphene liquid cells enabling researchers at the Lawrence Berkeley National Laboratory (Berkeley Lab) to make movies,

Through a combination of transmission electron microscopy (TEM) and their own unique graphene liquid cell, the researchers have recorded the three-dimensional motion of DNA connected to gold nanocrystals. This is the first time TEM has been used for 3D dynamic imaging of so-called soft materials.

The researchers have produced an animation illustrating their work,

The Oct. 3, 2013 Berkeley Lab news release, which originated the news item, goes on to describe the challenge of imaging soft materials and how the researchers solved the problem,

In the past, liquid cells featured silicon-based viewing windows whose thickness limited resolution and perturbed the natural state of the soft materials. Zettl [physicist Alex Zettl] and Alivisatos [Paul Alivisatos, Berkeley Lab Director] and their respective research groups overcame these limitations with the development of a liquid cell based on a graphene membrane only a single atom thick. This development was done in close cooperation with researchers at the National Center for Electron Microscopy (NCEM), which is located at Berkeley Lab.

“Our graphene liquid cells pushed the spatial resolution of liquid phase TEM imaging to the atomic scale but still focused on growth trajectories of metallic nanocrystals,” says lead author Qian Chen, a postdoctoral fellow in Alivisatos’s research group. “Now we’ve adopted the technique to imaging the 3D dynamics of soft materials, starting with double-strand (dsDNA) connected to gold nanocrystals and achieved nanometer resolution.”

To create the cell, two opposing graphene sheets are bonded to one another by their van der Waals attraction. This forms a sealed nanoscale chamber and creates within the chamber a stable aqueous solution pocket approximately 100 nanometers in height and one micron in diameter. The single atom thick graphene membrane of the cells is essentially transparent to the TEM electron beam, minimizing the unwanted loss of imaging electrons and providing superior contrast and resolution compared to silicon-based windows. The aqueous pockets allow for up to two minutes of continuous imaging of soft material samples exposed to a 200 kilo Volt imaging electron beam. During this time, soft material samples can freely rotate.

After demonstrating that their graphene liquid cell can seal an aqueous sample solution against a TEM high vacuum, the Berkeley researchers used it to study the types of gold-dsDNA nanoconjugates that have been widely used as dynamic plasmonic probes.

“The presence of double-stranded DNA molecules incorporates the major challenges of studying the dynamics of biological samples with liquid phase TEM,” says Alivisatos. “The high-contrast gold nanocrystals facilitate tracking of our specimens.”

The Alivisatos and Zettl groups were able to observe dimers, pairs of gold nanoparticles, tethered by a single piece of dsDNA, and trimers, three gold nanoparticles, connected into a linear configuration by two single pieces of dsDNA. From a series of 2D projected TEM images captured while the samples were rotating, the researchers were to reconstruct 3D configuration and motions of the samples as they evolved over time.