How To Convert CO2 In Energy

Imagine if carbon dioxide (CO2) could easily be converted into usable energy. Every time you breathe or drive a motor vehicle, you would produce a key ingredient for generating fuels. Like photosynthesis in plants, we could turn CO2 into molecules that are essential for day-to-day life. Now, scientists are one step closer. Researchers at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory are part of a scientific collaboration that has identified a new electrocatalyst that efficiently converts CO2 to carbon monoxide (CO), a highly energetic molecule. Their findings have been published  in Energy & Environmental Science.

Brookhaven scientists are pictured at NSLS-II beamline 8-ID, where they used ultra-bright x-ray light to “see” the chemical complexity of a new catalytic material. 

There are many ways to use CO,” said Eli Stavitski, a scientist at Brookhaven and an author on the paper. “You can react it with water to produce energy-rich hydrogen gas, or with hydrogen to produce useful chemicals, such as hydrocarbons or alcohols. If there were a sustainable, cost-efficient route to transform CO2 to CO, it would benefit society greatly.

Scientists have long sought a way to convert CO2 to CO, but traditional electrocatalysts cannot effectively initiate the reaction. That’s because a competing reaction, called the hydrogen evolution reaction (HER) or “water splitting,” takes precedence over the CO2 conversion reaction. A few noble metals, such as gold and platinum, can avoid HER and convert CO2 to CO; however, these metals are relatively rare and too expensive to serve as cost-efficient catalysts. So, to convert CO2 to CO in a cost-effective way, scientists used an entirely new form of catalyst. Instead of noble metal nanoparticles, they used single atoms of nickel.

Nickel metal, in bulk, has rarely been selected as a promising candidate for converting CO2 to CO,” said Haotian Wang, a Rowland Fellow at Harvard University and the corresponding author on the paper. “One reason is that it performs HER very well, and brings down the CO2 reduction selectivity dramatically. Another reason is because its surface can be easily poisoned by CO molecules if any are produced.”

Single atoms of nickel, however, produce a different result. “Single atoms prefer to produce CO, rather than performing the competing HER, because the surface of a bulk metal is very different from individual atoms,” Stavitski said. Klaus Attenkofer, also a Brookhaven scientist and a co-author on the paper, added, “The surface of a metal has one energy potential—it is uniform. Whereas on a single atom, every place on the surface has a different kind of energy.”

In addition to the unique energetic properties of single atoms, the CO2 conversion reaction was facilitated by the interaction of the nickel atoms with a surrounding sheet of graphene. Anchoring the atoms to graphene enabled the scientists to tune the catalyst and suppress HER.


Reconfigurable Materials

Metamaterialsmaterials whose function is determined by structure, not composition — have been designed to bend light and sound, transform from soft to stiff, and even dampen seismic waves from earthquakes. But each of these functions requires a unique mechanical structure, making these materials great for specific tasks, but difficult to implement broadly. But what if a material could contain within its structure, multiple functions and easily and autonomously switch between them?

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering at Harvard University have developed a general framework to design reconfigurable metamaterials. The design strategy is scale independent, meaning it can be applied to everything from meter-scale architectures to reconfigurable nano-scale systems such as photonic crystals, waveguides and metamaterials to guide heat.

In terms of reconfigurable metamaterials, the design space is incredibly large and so the challenge is to come up with smart strategies to explore it,” said Katia Bertoldi, John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. “Through a collaboration with designers and mathematicians, we found a way to generalize these rules and quickly generate a lot of interesting designs.”

The research is published in Nature.

Bionic Cardiac Patch

Scientists have built a “bioniccardiac patch that could act similarly to a pacemaker and monitor as well as respond to cardiac problems, a kind of nanocomputer. The researchers from Harvard University constructed nanoscale electronic scaffolds that can be seeded with cardiac cells to produce a bionic cardiac patch — the engineered heart tissue with ability to replace heart muscle damaged during a heart attack.

bionic cardiac patch

I think one of the biggest impacts would ultimately be in the area that involves replaced of damaged cardiac tissue with pre-formed tissue patches,” said Charles Lieber, who along with colleagues described the work in the journal Nature Nanotechnology. “Rather than simply implanting an engineered patch built on a passive scaffold, our works suggests it will be possible to surgically implant an innervated patch that would now be able to monitor and subtly adjust its performance,” he added.

Once implanted, the “bionic” patch could act similarly to a pacemakerdelivering electrical shocks to correct arrhythmia. Unlike traditional pacemakers, the “bionic” patch — because its electronic components are integrated throughout the tissue — can detect arrhythmia far sooner, and operate at far lower voltages. “Even before a person started to go into large-scale arrhythmia that frequently causes irreversible damage or other heart problems, this could detect the early-stage instabilities and intervene sooner,” Lieber said. “It can also continuously monitor the feedback from the tissue and actively respond,” he added.

The patch might also find use as a tool to monitor the responses under cardiac drugs, or to help pharmaceutical companies to screen the effectiveness of drugs under development.


How To Manipulate Light

Electrons are so 20th century. In the 21st century, photonic devices, which use light to transport large amounts of information quickly, will enhance or even replace the electronic devices that are ubiquitous in our lives today. But there’s a step needed before optical connections can be integrated into telecommunications systems and computers: researchers need to make it easier to manipulate light at the nanoscale.

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have done just that, designing the first on-chip metamaterial with a refractive index of zero, meaning that the phase of light can travel infinitely fast.

This new metamaterial was developed in the lab of Eric Mazur, the Balkanski Professor of Physics and Applied Physics and Area Dean for Applied Physics at SEAS, and is described in the journal Nature Photonics.

manipulated light

New zero-index material made of silicon pillar arrays embedded in a polymer matrix and clad in gold film creates a constant phase of light, which stretches out in infinitely long wavelengths

Light doesn’t typically like to be squeezed or manipulated but this metamaterial permits you to manipulate light from one chip to another, to squeeze, bend, twist and reduce diameter of a beam from the macroscale to the nanoscale,” said Mazur. “It’s a remarkable new way to manipulate light.”

Although this infinitely high velocity sounds like it breaks the rule of relativity, it doesn’t. Nothing in the universe travels faster than light carrying information — Einstein is still right about that. But light has another speed, measured by how fast the crests of a wavelength move, known as phase velocity. This speed of light increases or decreases depending on the material it’s moving through.

When light passes through water, for example, its phase velocity is reduced as its wavelengths get squished together. Once it exits the water, its phase velocity increases again as its wavelength elongates. How much the crests of a light wave slow down in a material is expressed as a ratio called the refraction index — the higher the index, the more the material interferes with the propagation of the wave crests of light. Water, for example, has a refraction index of about 1.3.

When the refraction index is reduced to zero, really weird and interesting things start to happen.


How To Fight Septic Shock, Save Millions

Last year, a Wyss Institute (Harvard) team of scientists described the development of a new device to treat sepsis that works by mimicking our spleen. It cleanses pathogens and toxins from blood circulating through a dialysis-like circuit. Now, the Wyss Institute team has developed an improved device that synergizes with conventional antibiotic therapies and that has been streamlined to better position it for near-term translation to the clinic. Sepsis is a common and frequently fatal medical complication that can occur when a person’s body attempts to fight off serious infection. Resulting widespread inflammation can cause organs to shut down, blood pressure to drop, and the heart to weaken. This can lead to septic shock, and more than 30 percent of septic patients in the United States eventually die. In most cases, the pathogen responsible for triggering the septic condition is never pinpointed, so clinicians blindly prescribe an antibiotic course in a blanket attempt to stave off infectious bacteria and halt the body’s dangerous inflammatory response.

But sepsis can be caused by a wide-ranging variety of pathogens that are not susceptible to antibiotics, including viruses, fungi and parasites. What’s more, even when antibiotics are effective at killing invading bacteria, the dead pathogens fragment and release toxins into the patient’s bloodstream.
The inflammatory cascade that leads to sepsis is triggered by pathogens, and specifically by the toxins they release,” said Wyss Institute Founding Director Donald Ingber, M.D., Ph.D., who leads the Wyss team developing the device and is the Judah Folkman Professor of Vascular Biology at Boston Children’s Hospital and Harvard Medical School and Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Science. “Thus, the most effective strategy is to treat with the best antibiotics you can muster, while also removing the toxins and remaining pathogens from the patient’s blood as quickly as possible.”

The Wyss team’s blood-cleansing approach can be administered quickly, even without identifying the infectious agent. This is because it uses the Wyss Institute‘s proprietary pathogen-capturing agent, FcMBL, that binds all types of live and dead infectious microbes, including bacteria, fungi, viruses, as well as toxins they release. FcMBL is a genetically engineered blood protein inspired by a naturally-occurring human molecule called Mannose Binding Lectin (MBL), which is found in the innate immune system and binds to toxic invaders, marking them for capture by immune cells in the spleen.

The findings are described in the October volume 67 of Biomaterials.


Perfect Image Of Brain Synaptic System

The human brain contains more synapses than there are galaxies in the observable universe (to put a number on it, there are perhaps 100 trillion synapses versus 100 billion galaxies), and now scientists can see them all – individually. A new imaging tool promises to open the door to all sorts of new insights about the brain and how it works. The tool can generate images at a nanoscale resolution, which is small enough to see all cellular objects and many of their sub-cellular components (so for the biology-literate, that’s stuff like neurons and the synapses that permit them to fire, plus axons, dendrites, glia, mitochondria, blood vessel cells, and so on).



Developed by researchers at the Boston University School of Medicine and Harvard University, the imaging method employs an automated tape-collecting device equipped with a diamond knife to obtain ultra-thin brain sections, which are then scanned under an electron microscope. Different colors are used to identify different cellular objects using software developed by study co-author Daniel Berger.

To demonstrate their new tool the researchers peered inside the brain of an adult mouse. They imaged a very small piece of a mouse’s neocortex at a resolution that made individual synaptic vesicles visible (these are tiny spheres of less than 40 nm diameter that store neurotransmitters, or chemical signals, for release from a synapse into a “target” neuron). The specific area they imaged is involved in receiving sensory information from mouse whiskers, which are much more sensitive than human fingertips.


Nanoelectronics Injected Directly Into The Brain

It’s a notion that might have come from the pages of a science-fiction novel — an electronic device that can be injected directly into the brain, or other body parts, and treat everything from neurodegenerative disorders to paralysis.

Led by Charles Lieber, Professor of Chemistry at Harvard University,  an international team of researchers has developed a method of fabricating nanoscale electronic scaffolds that can be injected via syringe. The scaffolds can then be connected to devices and used to monitor neural activity, stimulate tissues, or even promote regeneration of neurons.

brain synaptic symphonyI do feel that this has the potential to be revolutionary,” Lieber said. “This opens up a completely new frontier where we can explore the interface between electronic structures and biology. For the past 30 years, people have made incremental improvements in micro-fabrication techniques that have allowed us to make rigid probes smaller and smaller, but no one has addressed this issue — the electronics/cellular interface — at the level at which biology works.”

In an earlier study, scientists in Lieber’s lab demonstrated that cardiac or nerve cells grown with embedded scaffolds could be used to create “cyborgtissue. Researchers were then able to record electrical signals generated by the tissue, and to measure changes in those signals as they administered cardio– or neuro-stimulating drugs.

We were able to demonstrate that we could make this scaffold and culture cells within it, but we didn’t really have an idea how to insert that into pre-existing tissue,” Lieber said. “But if you want to study the brain or develop the tools to explore the brain-machine interface, you need to stick something into the body. When releasing the electronic scaffold completely from the fabrication substrate, we noticed that it was almost invisible and very flexible, like a polymer, and could literally be sucked into a glass needle or pipette. From there, we simply asked, ‘Would it be possible to deliver the mesh electronics by syringe needle injection?’

Though not the first attempt at implanting electronics into the braindeep brain stimulation has been used to treat a variety of disorders for decades — the nanofabricated scaffolds operate on a completely different scale.

Existing techniques are crude relative to the way the brain is wired,” Lieber said. “Whether it’s a silicon probe or flexible polymers … they cause inflammation in the tissue that requires periodically changing the position or the stimulation. But with our injectable electronics, it’s as if it’s not there at all. They are one million times more flexible than any state-of-the-art flexible electronics and have subcellular feature sizes. They’re what I call ‘neuro-philic’ — they actually like to interact with neurons.

The research is reported in Nature Nanotechnology.


A Nanocomputer 200 Times Smaller Than A Pinhead

The nanocomputer measures 0.3 x 0.03 millimeters (0.009 square millimeters) in size. To compare with a pinhead whose surface is 2 square millimeters. That means the nanocomputer built by the MITRE-Harvard researchers is 200 times smaller than a pinhead.
The interdisciplinary team of scientists and engineers from The MITRE Corporation (a non for profit US governmental organization) and Harvard University has taken key steps toward ultra-small electronic computer systems that push beyond the imminent end of Moore’s Law, which states that the device density and overall processing power for computers will double every two to three years. In a paper that has been published in the Proceedings of the National Academy of Sciences, the team describes how they designed and assembled, from the bottom up, a functioning, ultra-tiny control computer that is the densest nanoelectronic system ever built.

In the nanocomputer, nanoswitches are assembled and organized into circuits on severaltiles” (modules). Together, the tiles route small electronic signals around the computer, enabling it to perform calculations and process signals that could be used to control tiny systems, such as miniscule medical therapeutic devices, other tiny sensors and actuators, or even insect-sized robots
Construction of this nanocomputer was made possible by significant advances in processes that assemble with extreme precision dense arrays of the many nanodevices required. These advances also made it possible to manufacture multiple copies.
It was a challenge to develop a system architecture and nanocircuit designs that would pack the control functions we wanted into such a very tiny system,” according to Shamik Das, chief architect of the nanocomputer, who is also principal engineer and group leader of MITRE’s Nanosystems Group. “Once we had those designs, though, our Harvard collaborators did a brilliant job innovating to be able to realize them.”


How To Heat Your House At Night With Sun’s Energy

It’s an obvious truism, but one that may soon be outdated: The problem with solar power is that sometimes the sun doesn’t shine. Now a team at the Massachusetts Institute of Technology ( MIT) and Harvard University has come up with an ingenious workaround — a material that can absorb the sun’s heat and store that energy in chemical form, ready to be released again on demand. This solution is no solar-energy panacea: While it could produce electricity, it would be inefficient at doing so. But for applications where heat is the desired output — whether for heating buildings, cooking, or powering heat-based industrial processes — this could provide an opportunity for the expansion of solar power into new realms.

It could change the game, since it makes the sun’s energy, in the form of heat, storable and distributable,” says Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, who is a co-author of a paper describing the new process in the journal Nature Chemistry. Timothy Kucharski, a postdoc at MIT and Harvard, is the paper’s lead author.

How To Measure Risks From Nanomaterials In Contact With Cells

Scientists at the Center for Nanotechnology and Nanotoxicology at Harvard School of Public Health (HSPH) have discovered a fast, simple, and inexpensive method to measure the effective density of engineered nanoparticles in physiological fluids, thereby making it possible to accurately determine the amount of nanomaterials that come into contact with cells and tissue in culture. The new discovery will have a major impact on the hazard assessment of engineered nanoparticles, enabling risk assessors to perform accurate hazard rankings of nanomaterials using cellular systems. Furthermore, by measuring the composition of nanomaterial agglomerates in physiologic fluids, it will allow scientists to design more effective nano-based drug delivery systems for nanomedicine applications.
Thousands of consumer products containing engineered nanoparticles — microscopic particles found in everyday items from cosmetics and clothing to building materials — enter the market every year. Concerns about possible environmental health and safety issues of these nano-enabled products continue to grow with scientists struggling to come up with fast, cheap, and easy-to-use cellular screening systems to determine possible hazards of vast libraries of engineered nanomaterials. However, determining how much exposure to engineered nanoparticles could be unsafe for humans requires precise knowledge of the amount (dose) of nanomaterials interacting with cells and tissues such as lungs and skin

The biggest challenge we have in assessing possible health effects associated with nano exposures is deciding when something is hazardous and when it is not, based on the dose level. At low levels, the risks are probably miniscule,” said senior author Philip Demokritou, associate professor of aerosol physics in the Department of Environmental Health at HSPH. “The question is: At what dose level does nano-exposure become problematic? The same question applies to nano-based drugs when we test their efficiency using cellular systems. How much of the administered nano-drug will come in contact with cells and tissue? This will determine the effective dose needed for a given cellular response,” Demokritou said.


Bigger DNA Cages Enclose Drugs

Scientists at the Harvard’s Wyss Institute have built a set of self-assembling DNA cages one-tenth as wide as a bacterium. The structures are some of the largest and most complex ever constructed solely from DNA. DNA is best known as a keeper of genetic information. But scientists in the emerging field of DNA nanotechnology are exploring ways to use it to build tiny structures for a variety of applications. . In the future, scientists could potentially coat the DNA cages to enclose their contents, packaging drugs for delivery to tissues. And, like a roomy closet, the cage could be modified with chemical hooks that could be used to hang other components such as proteins or gold nanoparticles. This could help scientists build a variety of technologies, including tiny power plants, miniscule factories that produce specialty chemicals, or high-sensitivity photonic sensors that diagnose disease by detecting molecules produced by abnormal tissue.

The five cage-shaped DNA polyhedra here have struts stabilizing their legs, and this innovation allowed a Wyss Institute team to build by far the largest and sturdiest DNA cages yet. The largest, a hexagonal prism (right), is one-tenth the size of an average bacterium
Bioengineers interested in advancing the field of nanotechnology need to devise manufacturing methods that build sturdy components in a highly robust manner, and develop self-assembly methods that enable formation of nanoscale devices with defined structures and functions,” said Wyss Institute Founding Director Don Ingber, M.D., Ph.D. “DNA cages and the methods for visualizing the process in solution represent major advances along this path.”

I see exciting possibilities for this technology,” said Peng Yin, Ph.D., a Core Faculty member at the Wyss Institute and Assistant Professor of Systems Biology at Harvard Medical School, and senior author of the study.

The findings have been published in the online edition of Science.

Infrared, A Renewable Energy

Physicists from Harvard University propose a device to capture energy from earth”s infrared emissions to outer space. When the sun sets on a remote desert outpost and solar panels shut down, what energy source will provide power through the night? A battery, perhaps, or an old diesel generator? Perhaps something strange and new.
Physicists at the Harvard School of Engineering and Applied Sciences (SEAS) envision a device that would harvest energy from Earth’s infrared emissions into outer space. Heated by the sun, our planet is warm compared to the frigid vacuum beyond. Thanks to recent technological advances, the researchers say, that heat imbalance could soon be transformed into direct-current (DC) power, taking advantage of a vast and untapped energy source.

It’s not at all obvious, at first, how you would generate DC power by emitting infrared light in free space toward the cold,” says principal investigator Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at Harvard SEAS. “To generate power by emitting, not by absorbing light, that’s weird. It makes sense physically once you think about it, but it’s highly counterintuitive. We’re talking about the use of physics at the nanoscale for a completely new application.”
Their analysis of the thermodynamics, practical concerns, and technological requirements have been published in the Proceedings of the National Academy of Sciences.