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Home > Press > Weaving a new story for COFS and MOFs: First materials to be woven at the atomic and molecular levels created at Berkeley Abstract: There are many different ways to make nanomaterials but weaving, the oldest and most enduring method of making fabrics, has not been one of them - until now. An international collaboration led by scientists at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, has woven the first three-dimensional covalent organic frameworks (COFs) from helical organic threads. The woven COFs display significant advantages in structural flexibility, resiliency and reversibility over previous COFs - materials that are highly prized for their potential to capture and store carbon dioxide then convert it into valuable chemical products. "We have taken the art of weaving into the atomic and molecular level, giving us a powerful new way of manipulating matter with incredible precision in order to achieve unique and valuable mechanical properties," says Omar Yaghi, a chemist who holds joint appointments with Berkeley Lab's Materials Sciences Division and UC Berkeley's Chemistry Department, and is the co-director of the Kavli Energy NanoScience Institute (Kavli-ENSI). "Weaving in chemistry has been long sought after and is unknown in biology," Yaghi says. "However, we have found a way of weaving organic threads that enables us to design and make complex two- and three-dimensional organic extended structures." Yaghi is the corresponding author of a paper in Science reporting this new technique. The paper is titled "Weaving of organic threads into a crystalline covalent organic framework." The lead authors are Yuzhong Liu, Yanhang Ma and Yingbo Zhao. Other co-authors are Xixi Sun, Felipe Gándara, Hiroyasu Furukawa, Zheng Liu, Hanyu Zhu, Chenhui Zhu, Kazutomo Suenaga, Peter Oleynikov, Ahmad Alshammari, Xiang Zhang and Osamu Terasaki. COFs and their cousin materials, metal organic frameworks (MOFs), are porous three-dimensional crystals with extraordinarily large internal surface areas that can absorb and store enormous quantities of targeted molecules. Invented by Yaghi, COFs and MOFs consist of molecules (organics for COFs and metal-organics for MOFs) that are stitched into large and extended netlike frameworks whose structures are held together by strong chemical bonds. Such frameworks show great promise for, among other applications, carbon sequestration. Through another technique developed by Yaghi, called "reticular chemistry," these frameworks can also be embedded with catalysts to carry out desired functions: for example, reducing carbon dioxide into carbon monoxide, which serves as a primary building block for a wide range of chemical products including fuels, pharmaceuticals and plastics. In this latest study, Yaghi and his collaborators used a copper(I) complex as a template for bringing threads of the organic compound "phenanthroline" into a woven pattern to produce an immine-based framework they dubbed COF-505. Through X-ray and electron diffraction characterizations, the researchers discovered that the copper(I) ions can be reversibly removed or restored to COF-505 without changing its woven structure. Demetalation of the COF resulted in a tenfold increase in its elasticity and remetalation restored the COF to its original stiffness. "That our system can switch between two states of elasticity reversibly by a simple operation, the first such demonstration in an extended chemical structure, means that cycling between these states can be done repeatedly without degrading or altering the structure," Yaghi says. "Based on these results, it is easy to imagine the creation of molecular cloths that combine unusual resiliency, strength, flexibility and chemical variability in one material." Yaghi says that MOFs can also be woven as can all structures based on netlike frameworks. In addition, these woven structures can also be made as nanoparticles or polymers, which means they can be fabricated into thin films and electronic devices. "Our weaving technique allows long threads of covalently linked molecules to cross at regular intervals," Yaghi says. "These crossings serve as points of registry, so that the threads have many degrees of freedom to move away from and back to such points without collapsing the overall structure, a boon to making materials with exceptional mechanical properties and dynamics." ### This research was primarily supported by BASF (Germany) and King Abdulaziz City for Science and Technology (KACST). About Berkeley Lab Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | January 22, 2016
Site: www.rdmag.com

To understand what goes on inside a beehive you can't just study the activity of a single bee. Likewise, to understand the photosynthetic light-harvesting that takes place inside the chloroplast of a leaf, you can't just study the activity of a single antenna protein. Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory and the University of California (UC) Berkeley have created the first computational model that simulates the light-harvesting activity of the thousands of antenna proteins that would be interacting in the chloroplast of an actual leaf. The results from this model point the way to improving the yields of food and fuel crops, and developing artificial photosynthesis technologies for next generation solar energy systems. The new model simulates light-harvesting across several hundred nanometers of a thylakoid membrane, which is the membrane within a chloroplast that harbors photosystem II (PSII), a complex of antennae made up of mostly of chlorophyll-containing proteins. The antennae in PSII gain "excitation" energy when they absorb sunlight and, through quantum mechanical effects, almost instantaneously transport this extra energy to reaction centers for conversion into chemical energy. Previous models of PSII simulated energy transport within a single antenna protein. "Our model, which looked at some 10,000 proteins containing about 100,000 chlorophyll molecules, is the first to simulate a region of the PSII membrane large enough to represent behavior in a chloroplast while respecting and using both the quantum dynamics and the spatial structure of the membrane's components," says chemist Graham Fleming, who oversaw the development of this model. Fleming is a world authority on the quantum dynamics of photosynthesis. He holds appointments with Berkeley Lab, the University of California (UC) Berkeley, and the Kavli Energy NanoScience Institute at Berkeley. "We use insights from structural biology, advanced spectroscopy and theory to reproduce observed phenomena spanning from one nanometer to hundreds of nanometers, and from ten femtoseconds to one nanosecond," Fleming says. "This enables us to explain the mechanisms underlying the high quantum efficiency of PSII light harvesting in ideal conditions for the first time." Fleming is the corresponding author of a paper describing this research in the Proceedings of the National Academy of Sciences. The paper is titled "Multiscale model of photosystem II light harvesting in the thylakoid membrane of plants." Co-authors are Kapil Amarnath, Doran Bennett and Anna Schneider. The ability of green plants to thrive in sunlight stems in part from the flexibility that PSII displays in harvesting solar energy. At low levels of light, through quantum processes that have been modeled by Fleming and coworkers, a photon of sunlight can be utilized for creation of chemical energy with more than 90-percent probability. Thanks to a protective mechanism known as "energy-dependent quenching," PSII is able to ensure that a plant absorbs only the amount of solar energy it needs while excess energy that might damage the plant is safely dissipated. Earlier work by Fleming and his research group revealed a molecular mechanism by which PSII is able to act as a sort of photosynthetic "dimmer switch" to regulate the amount of solar energy transported to the reaction center. However, this work was done for a single PSII antenna and did not reflect how these mechanisms might affect the transport of energy across assemblies of antennae, which in turn would affect the photochemical yield in the reaction centers of a functional thylakoid membrane. "Our new model shows that excitation energy moves diffusively through the antennae with a diffusion length of 50 nanometers until it reaches a reaction center," Fleming says. "The diffusion length of this excitation energy determines PSII's high quantum efficiency in ideal conditions, and how that efficiency is altered by the membrane morphology and the closure of reaction centers. Ultimately, this means that the diffusion length of this excitation energy determines the photosynthetic efficiency of the host plant." Given that the ability of PSII to regulate the amount of solar energy being converted to chemical energy is essential for optimal plant fitness in natural sunlight, understanding this ability and learning to manipulate it is a prerequisite for systematically engineering the light-harvesting apparatus in crops. It should also be highly useful for designing artificial materials with the same flexible properties. "Our next step is to learn now to model a system of PSII's complexity over timescales ranging from femtoseconds to minutes, and lengthscales ranging from nanometers to micrometers," Fleming says.


News Article | February 15, 2017
Site: cen.acs.org

For extraordinary achievements in physical sciences and engineering, three chemists are among the five winners of this year’s National Academy of Sciences awards. A. Paul Alivisatos, professor of chemistry and materials science at the University of California, Berkeley, and director of the Kavli Energy NanoScience Institute, is the recipient of the $15,000 NAS Award in Chemical Sciences, which honors innovative research in the chemical sciences that contributes to a better understanding of the natural sciences and to the benefit of humanity. A pioneer in the field of nanotechnology, Alivisatos made important critical contributions to the development of quantum dots and applied those discoveries to biomedical imaging, a new generation of displays, and new types of solar cells. His work has also led to innovations in the control of nanocrystals and the graphene liquid cell for use in electron microscopy. He is founding director of the Molecular Foundry, a Department of Energy Nanoscale Science Research Center and founding editor of the ACS journal Nano Letters. Frances H. Arnold, the Dick and Barbara Dickinson Professor of Chemical Engineering, Bioengineering, and Biochemistry at California Institute of Technology, has won the $350,000 Raymond and Beverly Sackler Prize in Convergence Research, which recognizes significant advances in research that has resulted from the integration of two or more scientific disciplines. A pioneer in enzyme research, Arnold invented a technique called directed evolution, which helps breed proteins with desirable traits that would have been difficult or impossible to design. More recently, she has been developing enzymes that have no biological counterparts and that have tremendous implications for the creation of new types of catalysts. “Hard problems get solved when you can pull pieces of solutions from wherever you can find them,” Arnold says. “Admirers of evolution know that innovations can pop up from the oddest places. Mining some of those odd places, outside traditional disciplinary boundaries, can be lonely at times, but also very rewarding.” Leroy E. Hood, president of the Institute for Systems Biology, will receive the $20,000 NAS Award for Chemistry in Service to Society, presented every other year for contributions to chemistry, either in fundamental science or its application, that clearly satisfy a societal need. Hood invented, commercialized, and developed multiple chemical tools that address biological complexity, including the automated DNA sequencer which spearheaded the Human Genome Project. He has founded or cofounded 15 different biotechnology companies to help commercialize genomic and proteomic technologies. In 2000, Hood cofounded the Institute for Systems Biology, which was the first institute to practice systems biology. “My passion has always been to transfer relevant scientific knowledge to society and this award validates this lifelong philosophy as reflected in the commercialization of six instruments for reading and writing DNA and proteins,” Hood says. The awardees will be honored in a ceremony Sunday, April 30, during the National Academy of Sciences’ 154th annual meeting in Washington, D.C.


News Article | January 22, 2016
Site: www.rdmag.com

There are many different ways to make nanomaterials but weaving, the oldest and most enduring method of making fabrics, has not been one of them - until now. An international collaboration led by scientists at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, has woven the first three-dimensional covalent organic frameworks (COFs) from helical organic threads. The woven COFs display significant advantages in structural flexibility, resiliency and reversibility over previous COFs - materials that are highly prized for their potential to capture and store carbon dioxide then convert it into valuable chemical products. "We have taken the art of weaving into the atomic and molecular level, giving us a powerful new way of manipulating matter with incredible precision in order to achieve unique and valuable mechanical properties," says Omar Yaghi, a chemist who holds joint appointments with Berkeley Lab's Materials Sciences Division and UC Berkeley's Chemistry Department, and is the co-director of the Kavli Energy NanoScience Institute (Kavli-ENSI). "Weaving in chemistry has been long sought after and is unknown in biology," Yaghi says. "However, we have found a way of weaving organic threads that enables us to design and make complex two- and three-dimensional organic extended structures." Yaghi is the corresponding author of a paper in Science reporting this new technique. The paper is titled "Weaving of organic threads into a crystalline covalent organic framework." The lead authors are Yuzhong Liu, Yanhang Ma and Yingbo Zhao. Other co-authors are Xixi Sun, Felipe Gándara, Hiroyasu Furukawa, Zheng Liu, Hanyu Zhu, Chenhui Zhu, Kazutomo Suenaga, Peter Oleynikov, Ahmad Alshammari, Xiang Zhang and Osamu Terasaki. COFs and their cousin materials, metal organic frameworks (MOFs), are porous three-dimensional crystals with extraordinarily large internal surface areas that can absorb and store enormous quantities of targeted molecules. Invented by Yaghi, COFs and MOFs consist of molecules (organics for COFs and metal-organics for MOFs) that are stitched into large and extended netlike frameworks whose structures are held together by strong chemical bonds. Such frameworks show great promise for, among other applications, carbon sequestration. Through another technique developed by Yaghi, called "reticular chemistry," these frameworks can also be embedded with catalysts to carry out desired functions: for example, reducing carbon dioxide into carbon monoxide, which serves as a primary building block for a wide range of chemical products including fuels, pharmaceuticals and plastics. In this latest study, Yaghi and his collaborators used a copper(I) complex as a template for bringing threads of the organic compound "phenanthroline" into a woven pattern to produce an immine-based framework they dubbed COF-505. Through X-ray and electron diffraction characterizations, the researchers discovered that the copper(I) ions can be reversibly removed or restored to COF-505 without changing its woven structure. Demetalation of the COF resulted in a tenfold increase in its elasticity and remetalation restored the COF to its original stiffness. "That our system can switch between two states of elasticity reversibly by a simple operation, the first such demonstration in an extended chemical structure, means that cycling between these states can be done repeatedly without degrading or altering the structure," Yaghi says. "Based on these results, it is easy to imagine the creation of molecular cloths that combine unusual resiliency, strength, flexibility and chemical variability in one material." Yaghi says that MOFs can also be woven as can all structures based on netlike frameworks. In addition, these woven structures can also be made as nanoparticles or polymers, which means they can be fabricated into thin films and electronic devices. "Our weaving technique allows long threads of covalently linked molecules to cross at regular intervals," Yaghi says. "These crossings serve as points of registry, so that the threads have many degrees of freedom to move away from and back to such points without collapsing the overall structure, a boon to making materials with exceptional mechanical properties and dynamics."


News Article | January 19, 2016
Site: phys.org

This first computational model to simulate multiple antenna proteins, photosystem II (PSII) complexes are shown in teals, and light harvesting complexes (LHC II) are shown in green. To understand what goes on inside a beehive you can't just study the activity of a single bee. Likewise, to understand the photosynthetic light-harvesting that takes place inside the chloroplast of a leaf, you can't just study the activity of a single antenna protein. Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory and the University of California (UC) Berkeley have created the first computational model that simulates the light-harvesting activity of the thousands of antenna proteins that would be interacting in the chloroplast of an actual leaf. The results from this model point the way to improving the yields of food and fuel crops, and developing artificial photosynthesis technologies for next generation solar energy systems. The new model simulates light-harvesting across several hundred nanometers of a thylakoid membrane, which is the membrane within a chloroplast that harbors photosystem II (PSII), a complex of antennae made up of mostly of chlorophyll-containing proteins. The antennae in PSII gain "excitation" energy when they absorb sunlight and, through quantum mechanical effects, almost instantaneously transport this extra energy to reaction centers for conversion into chemical energy. Previous models of PSII simulated energy transport within a single antenna protein. "Our model, which looked at some 10,000 proteins containing about 100,000 chlorophyll molecules, is the first to simulate a region of the PSII membrane large enough to represent behavior in a chloroplast while respecting and using both the quantum dynamics and the spatial structure of the membrane's components," says chemist Graham Fleming, who oversaw the development of this model. Fleming is a world authority on the quantum dynamics of photosynthesis. He holds appointments with Berkeley Lab, the University of California (UC) Berkeley, and the Kavli Energy NanoScience Institute at Berkeley. "We use insights from structural biology, advanced spectroscopy and theory to reproduce observed phenomena spanning from one nanometer to hundreds of nanometers, and from ten femtoseconds to one nanosecond," Fleming says. "This enables us to explain the mechanisms underlying the high quantum efficiency of PSII light harvesting in ideal conditions for the first time." Fleming is the corresponding author of a paper describing this research in the Proceedings of the National Academy of Sciences. The paper is titled "Multiscale model of photosystem II light harvesting in the thylakoid membrane of plants." Co-authors are Kapil Amarnath, Doran Bennett and Anna Schneider. The ability of green plants to thrive in sunlight stems in part from the flexibility that PSII displays in harvesting solar energy. At low levels of light, through quantum processes that have been modeled by Fleming and coworkers, a photon of sunlight can be utilized for creation of chemical energy with more than 90-percent probability. Thanks to a protective mechanism known as "energy-dependent quenching," PSII is able to ensure that a plant absorbs only the amount of solar energy it needs while excess energy that might damage the plant is safely dissipated. Earlier work by Fleming and his research group revealed a molecular mechanism by which PSII is able to act as a sort of photosynthetic "dimmer switch" to regulate the amount of solar energy transported to the reaction center. However, this work was done for a single PSII antenna and did not reflect how these mechanisms might affect the transport of energy across assemblies of antennae, which in turn would affect the photochemical yield in the reaction centers of a functional thylakoid membrane. "Our new model shows that excitation energy moves diffusively through the antennae with a diffusion length of 50 nanometers until it reaches a reaction center," Fleming says. "The diffusion length of this excitation energy determines PSII's high quantum efficiency in ideal conditions, and how that efficiency is altered by the membrane morphology and the closure of reaction centers. Ultimately, this means that the diffusion length of this excitation energy determines the photosynthetic efficiency of the host plant." Given that the ability of PSII to regulate the amount of solar energy being converted to chemical energy is essential for optimal plant fitness in natural sunlight, understanding this ability and learning to manipulate it is a prerequisite for systematically engineering the light-harvesting apparatus in crops. It should also be highly useful for designing artificial materials with the same flexible properties. "Our next step is to learn now to model a system of PSII's complexity over timescales ranging from femtoseconds to minutes, and lengthscales ranging from nanometers to micrometers," Fleming says. Explore further: Lessons to be learned from nature in photosynthesis More information: Multiscale model of photosystem II light harvesting in the thylakoid membrane of plants, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1524999113


Home > Press > Seeing the big picture in photosynthetic light harvesting: Berkeley Lab researchers create first multiple antennae model of photosystem II Abstract: To understand what goes on inside a beehive you can't just study the activity of a single bee. Likewise, to understand the photosynthetic light-harvesting that takes place inside the chloroplast of a leaf, you can't just study the activity of a single antenna protein. Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory and the University of California (UC) Berkeley have created the first computational model that simulates the light-harvesting activity of the thousands of antenna proteins that would be interacting in the chloroplast of an actual leaf. The results from this model point the way to improving the yields of food and fuel crops, and developing artificial photosynthesis technologies for next generation solar energy systems. The new model simulates light-harvesting across several hundred nanometers of a thylakoid membrane, which is the membrane within a chloroplast that harbors photosystem II (PSII), a complex of antennae made up of mostly of chlorophyll-containing proteins. The antennae in PSII gain "excitation" energy when they absorb sunlight and, through quantum mechanical effects, almost instantaneously transport this extra energy to reaction centers for conversion into chemical energy. Previous models of PSII simulated energy transport within a single antenna protein. "Our model, which looked at some 10,000 proteins containing about 100,000 chlorophyll molecules, is the first to simulate a region of the PSII membrane large enough to represent behavior in a chloroplast while respecting and using both the quantum dynamics and the spatial structure of the membrane's components," says chemist Graham Fleming, who oversaw the development of this model. Fleming is a world authority on the quantum dynamics of photosynthesis. He holds appointments with Berkeley Lab, the University of California (UC) Berkeley, and the Kavli Energy NanoScience Institute at Berkeley. "We use insights from structural biology, advanced spectroscopy and theory to reproduce observed phenomena spanning from one nanometer to hundreds of nanometers, and from ten femtoseconds to one nanosecond," Fleming says. "This enables us to explain the mechanisms underlying the high quantum efficiency of PSII light harvesting in ideal conditions for the first time." Fleming is the corresponding author of a paper describing this research in the Proceedings of the National Academy of Sciences. The paper is titled "Multiscale model of photosystem II light harvesting in the thylakoid membrane of plants." Co-authors are Kapil Amarnath, Doran Bennett and Anna Schneider. The ability of green plants to thrive in sunlight stems in part from the flexibility that PSII displays in harvesting solar energy. At low levels of light, through quantum processes that have been modeled by Fleming and coworkers, a photon of sunlight can be utilized for creation of chemical energy with more than 90-percent probability. Thanks to a protective mechanism known as "energy-dependent quenching," PSII is able to ensure that a plant absorbs only the amount of solar energy it needs while excess energy that might damage the plant is safely dissipated. Earlier work by Fleming and his research group revealed a molecular mechanism by which PSII is able to act as a sort of photosynthetic "dimmer switch" to regulate the amount of solar energy transported to the reaction center. However, this work was done for a single PSII antenna and did not reflect how these mechanisms might affect the transport of energy across assemblies of antennae, which in turn would affect the photochemical yield in the reaction centers of a functional thylakoid membrane. "Our new model shows that excitation energy moves diffusively through the antennae with a diffusion length of 50 nanometers until it reaches a reaction center," Fleming says. "The diffusion length of this excitation energy determines PSII's high quantum efficiency in ideal conditions, and how that efficiency is altered by the membrane morphology and the closure of reaction centers. Ultimately, this means that the diffusion length of this excitation energy determines the photosynthetic efficiency of the host plant." Given that the ability of PSII to regulate the amount of solar energy being converted to chemical energy is essential for optimal plant fitness in natural sunlight, understanding this ability and learning to manipulate it is a prerequisite for systematically engineering the light-harvesting apparatus in crops. It should also be highly useful for designing artificial materials with the same flexible properties. "Our next step is to learn now to model a system of PSII's complexity over timescales ranging from femtoseconds to minutes, and lengthscales ranging from nanometers to micrometers," Fleming says. ### This research was supported by the DOE Office of Science. Computational work was carried out at the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility hosted at Berkeley Lab. About Berkeley Lab Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit www.lbl.gov. The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Home > Press > How to train your bacterium: Berkeley Lab scientists teach bacterium a new trick for artificial photosynthesis Abstract: Trainers of dogs, horses, and other animal performers take note: a bacterium named Moorella thermoacetica has been induced to perform only a single trick, but it's a doozy. Berkeley Lab researchers are using M. thermoacetica to perform photosynthesis - despite being non-photosynthetic - and also to synthesize semiconductor nanoparticles in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products. "We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this work. "The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we've created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism," Yang says. "Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies." Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled "Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production." Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. "In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst," Yang says. "By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction." Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. "Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology," Yang says. "In this study, we've demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications." ### This work was funded by the U.S. Department of Energy (DOE)'s Office of Science. The interface design part of the study was carried out the Molecular Foundry, a DOE Office Science User Facility hosted by Berkeley Lab. About Berkeley Lab Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit www.lbl.gov. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website at science.energy.gov/. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | January 5, 2016
Site: www.rdmag.com

Trainers of dogs, horses, and other animal performers take note: a bacterium named Moorella thermoacetica has been induced to perform only a single trick, but it's a doozy. Berkeley Lab researchers are using M. thermoacetica to perform photosynthesis - despite being non-photosynthetic - and also to synthesize semiconductor nanoparticles in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products. "We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this work. "The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we've created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism," Yang says. "Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies." Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled "Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production." Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. "In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst," Yang says. "By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction." Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. "Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology," Yang says. "In this study, we've demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications."


News Article | January 4, 2016
Site: phys.org

"We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this work. "The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we've created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism," Yang says. "Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies." Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled "Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production." Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. "In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst," Yang says. "By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction." Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. "Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology," Yang says. "In this study, we've demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications." Explore further: Major advance in artificial photosynthesis poses win/win for the environment More information: K. K. Sakimoto et al. Self-photosensitization of nonphotosynthetic bacteria for solar-to-chemical production, Science (2015). DOI: 10.1126/science.aad3317


News Article | January 5, 2016
Site: www.cemag.us

Trainers of dogs, horses, and other animal performers take note: a bacterium named Moorella thermoacetica has been induced to perform only a single trick, but it’s a doozy. Berkeley Lab researchers are using M. thermoacetica to perform photosynthesis — despite being non-photosynthetic — and also to synthesize semiconductor nanoparticles in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products. “We’ve demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis,” says Peidong Yang, a chemist with Berkeley Lab’s Materials Sciences Division, who led this work. “The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we’ve created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism,” Yang says. “Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies.” Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled “Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production.” Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. “In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst,” Yang says. “By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction.” Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an “electrograph” (meaning it can undergo direct electron transfers from an electrode), and an “acetogen” (meaning it can direct nearly 90 percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. “Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology,” Yang says. “In this study, we’ve demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications.” This work was funded by the U.S. Department of Energy (DOE)’s Office of Science. The interface design part of the study was carried out the Molecular Foundry, a DOE Office Science User Facility hosted by Berkeley Lab. Release Date: January 5, 2016 Source: Berkeley Lab

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