#Recycling old batteries into solar cells This could be a classic win-win solution: A system proposed by researchers at MIT recycles materials from discarded car batteries a potential source of lead pollution into new,
long-lasting solar panels that provide emissions-free power. The system is described in a paper in the journal Energy and Environmental science,
co-authored by professors Angela M. Belcher and Paula T. Hammond, graduate student Po-Yen Chen,
and three others. It is based on a recent development in solar cells that makes use of a compound called perovskite specifically,
organolead halide perovskite a technology that has progressed rapidly from initial experiments to a point where its efficiency is nearly competitive with that of other types of solar cells. t went from initial demonstrations to good efficiency in less than two years,
says Belcher, the W. M. Keck Professor of Energy at MIT. Already, perovskite-based photovoltaic cells have achieved power-conversion efficiency of more than 19 percent,
which is close to that of many commercial silicon-based solar cells. Initial descriptions of the perovskite technology identified its use of lead,
whose production from raw ores can produce toxic residues, as a drawback. But by using recycled lead from old car batteries,
the manufacturing process can instead be used to divert toxic material from landfills and reuse it in photovoltaic panels that could go on producing power for decades.
Amazingly because the perovskite photovoltaic material takes the form of a thin film just half a micrometer thick,
the team analysis shows that the lead from a single car battery could produce enough solar panels to provide power for 30 households.
As an added advantage, the production of perovskite solar cells is a relatively simple and benign process. t has the advantage of being a low-temperature process,
and the number of steps is reducedcompared with the manufacture of conventional solar cells, Belcher says.
Those factors will help to make it asy to get to large scale cheaply Chen adds. Battery pileup ahead One motivation for using the lead in old car batteries is that battery technology is undergoing rapid change, with new, more efficient types, such as lithium-ion batteries,
swiftly taking over the market. nce the battery technology evolves, over 200 million lead-acid batteries will potentially be retired in the United states,
and that could cause a lot of environmental issues, Belcher says. Today, she says, 90 percent of the lead recovered from the recycling of old batteries is used to produce new batteries,
but over time the market for new lead-acid batteries is likely to decline, potentially leaving a large stockpile of lead with no obvious application.
In a finished solar panel, the lead-containing layer would be encapsulated fully by other materials, as many solar panels are today,
limiting the risk of lead contamination of the environment. When the panels are retired eventually, the lead can simply be recycled into new solar panels. he process to encapsulate them will be the same as for polymer cells today,
Chen says. hat technology can be translated easily. t is important that we consider the life cycles of the materials in large-scale energy systems,
Hammond says. nd here we believe the sheer simplicity of the approach bodes well for its commercial implementation.
Old lead is as good as new Belcher believes that the recycled perovskite solar cells will be embraced by other photovoltaics researchers,
who can now fine-tune the technology for maximum efficiency. The team work clearly demonstrates that lead recovered from old batteries is
just as good for the production of perovskite solar cells as freshly produced metal. Some companies are already gearing up for commercial production of perovskite photovoltaic panels,
which could otherwise require new sources of lead. Since this could expose miners and smelters to toxic fumes
the introduction of recycling instead could provide immediate benefits, the team says. Yang Yang, a professor of materials science and engineering at the University of California at Los angeles who was involved not in this research,
says, ow, what an interesting paper, that turns the waste of one system into a valuable resource for another!
I think the work demonstrated here can resolve a major issue of industrial waste, and provide a solution for future renewable energy.
The work, which also included research scientist Jifa Qi, graduate student Matthew Klug and postdoc Xiangnan Dang, was supported by Italian energy company Eni through the MIT Energy Initiative y
#RNA combination therapy for lung cancer offers promise for personalized medicine Small RNA molecules including micrornas (mirnas)
and small interfering RNAS (sirnas) offer tremendous potential as new therapeutic agents to inhibit cancer-cell growth.
However delivering these small RNAS to solid tumors remains a significant challenge as the RNAS must target the correct cells
and avoid being broken down by enzymes in the body. To date most work in this area has focused on delivery to the liver where targeting is relatively straightforward.
This week in the journal Proceedings of the National Academy of Sciences researchers at the Koch Institute for Integrative Cancer Research at MIT report that they have delivered successfully small RNA therapies in a clinically relevant mouse model of lung cancer to slow
and shrink tumor growth. Their research offers promise for personalized RNA combination therapies to improve therapeutic response.
Delivering combination therapiesusing the KP mouse model in which a mutant form of the oncogene KRAS is activated
and tumor-suppressor gene p53 is deleted researchers injected mice with RNA-carrying nanoparticles. This mouse model reflects many of the hallmarks of human lung cancer
and is used often in preclinical trials. It was developed originally in the laboratory of Koch Institute Director#Tyler Jacks the#David H. Koch Professor of Biology#who is co-senior author of this paper.
The nanoparticles are made of a small polymer lipid conjugate; unlike liver-targeting nanoparticles these preferentially target the lung
and are tolerated well in the body. They were developed in the laboratories of co-senior author Daniel G. Anderson the Samuel A. Goldblith Associate professor of Chemical engineering an affiliate of MIT's Institute of Medical Engineering and Science;
and author Robert Langer the David H. Koch Institute Professor. In this study researchers tested the nanoparticle-delivery system with different payloads of therapeutic RNA.
They found that delivery of mir-34a a p53-regulated mirna slowed tumor growth as did delivery of sikras a KRAS-targeting sirna.
Next researchers treated mice with both mir-34a and sikras in the same nanoparticle. Instead of just slowing tumor growth this combination therapy caused tumors to regress
and shrink to about 50 percent of their original size. Researchers then compared mouse survival time among four treatment options:#
#no treatment; treatment with cisplatin a small-molecule standard-care chemotherapy drug; treatment#with nanoparticles carrying both mir-34a and sikras;
and treatment#with both cisplatin and the nanoparticles. They found that the nanoparticle treatment extended life just as well as the cisplatin treatment and furthermore that the combination therapy of the nanoparticles and cisplatin together extended life by about an additional 25 percent.
Potential for personalized cancer treatmentsthis early example of RNA combination therapy demonstrates the potential of developing personalized cancer treatments.
With efficient delivery of therapeutic RNA any individual small RNA or combination of RNAS could be deployed to regulate the genetic mutations underlying a given patient s cancer.
Furthermore these RNA therapies could be combined with more traditional drug therapies for an enhanced effect.
Small-RNA therapy holds great promise for cancer Jacks#says. It is appreciated widely that the major hurdle in this field is efficient delivery to solid tumors outside of the liver
and this work goes a long way in showing that this is achievable. RNA therapies are very flexible
and have a lot of potential because you can design them to treat any type of disease by modifying gene expression very specifically says James Dahlman a graduate student in Anderson s
and Langer s laboratories who along with senior postdoc#Wen Xue of Jacks laboratory is co-first author of the paper.
We took the best mouse model for lung cancer we could find we found the best nanoparticle we could use
and for one of the first times we demonstrate targeted RNA combination therapy in a clinically#relevant model of lung cancer.
This investigation typifies the Koch Institute s model of bringing biologists and engineers together to engage in interdisciplinary cancer research.
This study is a terrific example of the potential of new RNA therapies to treat disease that was done in a highly collaborative way between biologists
and engineers Langer#says. It s an example of what makes the Koch Institute very special.
Contributors to this research from Langer s and Anderson s laboratories include postdocs Omar Khan and#Gaurav Sahay former postdoc#Avi Schroeder and Apeksha Dave'13.
Contributors from Jacks laboratory include postdoc Tuomas Tammela Sabina Sood'13 MIT junior Gillian Yang and former research technicians Wenxin Cai#and Leilani Chirino.
This research was supported by grant funding from the National institutes of health and the National Cancer Institute e
#New analysis reveals tumor weaknesses Scientists have known for decades that cancer can be caused by genetic mutations
but more recently they have discovered that chemical modifications of a gene can also contribute to cancer.
These alterations known as epigenetic modifications control whether a gene is turned on or off. Analyzing these modifications can provide important clues to the type of tumor a patient has
and how it will respond to different drugs. For example patients with glioblastoma a type of brain tumor respond well to a certain class of drugs known as alkylating agents
if the DNA-repair gene MGMT is silenced by epigenetic modification. A team of MIT chemical engineers has developed now a fast reliable method to detect this type of modification known as methylation which could offer a new way to choose the best treatment for individual patients.
It s pretty difficult to analyze these modifications which is need a that we re working on addressing.
We re trying to make this analysis easier and cheaper particularly in patient samples says Hadley Sikes an assistant professor of chemical engineering
and the senior author of a paper describing the technique in the journal Analyst. The paper s lead author is Brandon Heimer an MIT graduate student in chemical engineering.
Beyond the genomeafter sequencing the human genome scientists turned to the epigenome the chemical modifications including methylation that alter a gene s function without changing its DNA sequence.
In some cancers the MGMT gene is turned off when methyl groups attach to specific locations in the DNA sequence namely cytosine bases that are adjacent to guanine bases.
When this happens proteins bind the methylated bases and effectively silence the gene by blocking it from being copied into RNA.
This very small chemical modification triggers a sequence of events where that gene is expressed no longer Sikes says.
Current methods for detecting cytosine methylation work well for large-scale research studies but are hard to adapt to patient samples Sikes says.
Most techniques require a chemical step called bisulfite conversion: The DNA sample is exposed to bisulfite
which converts unmethylated cytosine to a different base. Sequencing the DNA reveals whether any methylated cytosine was present.
However this method doesn t work well with patient samples because you need to know precisely how much methylated DNA is in a sample to calculate how long to expose it to bisulfite Sikes says.
When you have limited amounts of samples that are defined less well it s a lot harder to run the reaction for the right amount of time.
You want to get all of the unmethylated cytosine groups converted but you can t run it too long
because then your DNA gets degraded she says. Rapid detectionsikes new approach avoids bisulfite conversion completely.
Instead it relies on a protein called a methyl binding domain (MBD) protein which is part of cells natural machinery for controlling DNA transcription.
This protein recognizes methylated DNA and binds to it helping a cell to determine if the DNA should be transcribed.
The other key component of Sikes system is a biochip a glass slide coated with hundreds of DNA PROBES that are complementary to sequences from the gene being studied.
When a DNA sample is exposed to this chip any strands that match the target sequences are trapped on the biochip.
The researchers then treat the slide with the MBD protein probe. If the probe binds to a trapped DNA molecule it means that sequence is methylated.
The binding between the DNA and the MBD protein can be detected either by linking the protein to a fluorescent dye
or designing it to carry a photosensitive molecule that forms hydrogels when exposed to light.
This technique which cuts the amount of time required to analyze epigenetic modifications could be a valuable research tool as well as a diagnostic device for cancer patients says Andrea Armani a professor of chemical engineering
and materials science at the University of Southern California who was not part of the research team.
It s a really innovative approach Armani says. Not only could it impact diagnostics but on a broader scale it could impact our understanding
of which epigenetic markers are linked to which diseases. The MIT team is now adapting the device to detect methylation of other cancer-linked genes by changing the DNA sequences of the biochip probes.
They also hope to create better versions of the MBD protein and to engineer the device to require less DNA.
With the current version doctors would need to do a surgical biopsy to get enough tissue
but the researchers would like to modify it so the test could be done with just a needle biopsy.
The research was funded by a David H. Koch fellowship a National Science Foundation fellowship a Burroughs Wellcome Fund Career Award the National Institute for Environmental Health Sciences and the James
H. Ferry Fund for Innovation n
#An easier way to manipulate malaria genes Plasmodium falciparum the parasite that causes malaria has proven notoriously resistant to scientists efforts to study its genetics.
It can take up to a year to determine the function of a single gene which has slowed efforts to develop new more targeted drugs and vaccines.
MIT biological engineers have demonstrated now that a new genome-editing technique called CRISPR can disrupt a single parasite gene with a success rate of up to 100 percent in a matter of weeks.
This approach could enable much more rapid gene analysis and boost drug-development efforts says Jacquin Niles an associate professor of biological engineering at MIT.
Even though we ve sequenced the entire genome of Plasmodium falciparum half of it still remains functionally uncharacterized.
That s about 2500 genes that if only we knew what they did we could think about novel therapeutics
whether it s drugs or vaccines says Niles the senior author of a paper describing the technique in the Aug 10 online edition of Nature Methods.
The paper s lead author is Jeffrey Wagner a recent Phd recipient and current MIT postdoc in biological engineering.
Graduate student Randall Platt recent Phd recipient Stephen Goldfless and Feng Zhang the W. M. Keck Career development Assistant professor in Biomedical engineering also contributed to the research.
Plasmodium falciparum a blood-borne parasite carried by mosquitoes is responsible for most of the estimated 219 million cases and 655000 deaths from malaria per year.
Treatments include chloroquine and artemisin but the parasite is becoming more resistant to these drugs.
There is an urgent need to develop new drugs but potential genetic targets are hard to identify.
In animals such as mice it is fairly routine to study gene functions by deleting a target gene or replacing it with an artificial piece of DNA.
However in Plasmodium falciparum this approach can take up to a year because it relies on homologous recombination a type of genetic swapping that cells use to repair broken DNA strands.
This occurs very rarely in the genome of the malaria parasite. You have to rely on this really inefficient process that occurs
CRISPR a gene-editing system devised within the past several years exploits a set of bacterial proteins that protect microbes from viral infection.
The system includes a DNA-cutting enzyme Cas9 bound to a short RNA guide strand that is programmed to bind to a specific genome sequence telling Cas9 where to make its cut.
Photo courtesy of the researchersfull Screen As soon as researchers successfully demonstrated that this system could work in cells other than bacteria Niles started to think about using it to manipulate Plasmodium falciparum.
and eba-175 that had previously been knocked out in malaria using traditional approaches. The kahrp gene produces a protein that causes red blood cells
when infected with malaria. Niles team was able to disrupt this gene in 100 percent of parasites treated with the CRISPR system;
which P. falciparum genetics have been done in the past even 50 percent is pretty substantial. For both targets the researchers demonstrated that they could insert a gene for the protein luciferase
The general concept of using the CRISPR/Cas9 system to edit the genome of the malaria parasite is significant
because we ve struggled with the technical aspects of doing these genetic experiments says Kirk Deitsch a professor of microbiology
and immunology at Cornell University who was not part of the research team. Now based on CRISPR we can modify genes in a shorter timeframe and with greatly enhanced precision.
which could generate new drug and vaccine targets. I think the impact could be quite huge Niles says.
The research was funded by the National Institute of General Medical sciences the National Institute of Environmental Health Sciences the National Science Foundation the National institutes of health and the Bill and Melinda Gates Foundation n
and crawls away as soon as batteries are attached to it. The exciting thing here is that you create this device that has embedded computation in the flat printed version says Daniela Rus the Andrew
and Erna Viterbi Professor of Electrical engineering and Computer science at MIT and one of the Science paper s co-authors.
And when these devices lift up from the ground into the third dimension they do it in a thoughtful way.
Rus is joined on the paper by Erik Demaine an MIT professor of computer science and engineering and by three researchers at Harvard s Wyss Institute for Biologically Inspired Engineering and School of Engineering and Applied sciences:
The new work is similar but a network of electrical leads rather than an oven or hot plate delivers heat to the robot s joints to initiate folding.
That s exciting from a geometry standpoint Demaine says because it lets us fold more things.
the outer layers are composed of a shape-memory polymer that folds when heated. After the laser-cut materials are layered together a microprocessor
and one or more small motors are attached to the top surface. In the prototype that attachment was done manually
Each motor controls two of the robot s legs; the motors are synchronized by the microprocessor. Each leg in turn has eight mechanical linkages
and the dynamics of the linkages convert the force exerted by the motor into movement.
In prior work Rus Demaine and Wood developed an algorithm that could automatically convert any digitally specified 3-D shape into an origami folding pattern.
what s called a cyclic fold where you have a bunch of panels connected together in a cycle
But as Demaine explains in origami 180-degree folds are used generally to join panels together.
With 150-degree folds the panels won t quite touch but that s probably tolerable for many applications In the meantime Demaine is planning to revisit the theoretical analysis that was the basis of the researchers original folding algorithm to determine
whether it s still possible to produce arbitrary three-dimensional shapes with folds no sharper than 150 degrees.
This is the first time where they ve self-folded such a complicated robotic structure says Ronald Fearing a professor of electrical engineering
and computer science at the University of California at Berkeley who has been following the MIT and Harvard researchers work.
Because they build it with the electronics on first you can now choose which folds occur when.
If you don t have the electronics then you re limited to patterns where you heat up the whole thing
The work was funded by the National Science Foundation the Wyss Institute for Biologically Inspired Research at Harvard and the Air force Office of Scientific research h
#A new way to model cancer Sequencing the genomes of tumor cells has revealed thousands of mutations associated with cancer.
One way to discover the role of these mutations is breed to a strain of mice that carry the genetic flaw
but breeding such mice is an expensive time-consuming process. Now MIT researchers have found an alternative:
They have shown that a gene-editing system called CRISPR can introduce cancer-causing mutations into the livers of adult mice enabling scientists to screen these mutations much more quickly.
In a study appearing in the Aug 6 issue of Nature the researchers generated liver tumors in adult mice by disrupting the tumor suppressor genes p53 and pten.
They are now working on ways to deliver the necessary CRISPR components to other organs allowing them to investigate mutations found in other types of cancer.
The sequencing of human tumors has revealed hundreds of oncogenes and tumor suppressor genes in different combinations.
The flexibility of this technology as delivery gets better in the future will give you a way to pretty rapidly test those combinations says Institute Professor Phillip Sharp an author of the paper.
Tyler Jacks director of MIT s Koch Institute for Integrative Cancer Research and the David H. Koch Professor of Biology is the paper s senior author.
Gene disruptioncrispr relies on cellular machinery that bacteria use to defend themselves from viral infection.
Researchers have copied this bacterial system to create gene-editing complexes that include a DNA-cutting enzyme called Cas9 bound to a short RNA guide strand that is programmed to bind to a specific genome sequence telling Cas9 where to make its Cut in some cases the researchers simply snip out
To investigate the potential usefulness of CRISPR for creating mouse models of cancer the researchers first used it to knock out p53 and pten
Previous studies have shown that genetically engineered mice with mutations in both of those genes will develop cancer within a few months.
which requires introducing mutations into embryonic stem cells can take more than a year and costs hundreds of thousands of dollars.
and pten the researchers were able to disrupt those two genes in about 3 percent of liver cells enough to produce liver tumors within three months.
Many models possiblethe researchers also used CRISPR to create a mouse model with an oncogene called beta catenin
if additional mutations occur later on. To create this model the researchers had to cut out the normal version of the gene
Using CRISPR to generate tumors should allow scientists to more rapidly study how different genetic mutations interact to produce cancers as well as the effects of potential drugs on tumors with a specific genetic profile.
This is a game-changer for the production of engineered strains of human cancer says Ronald Depinho director of the University of Texas MD Anderson Cancer Center who was not part of the research team.
Enhanced potential of this powerful technology will be realized with improved delivery methods the testing of#CRISPR/Cas9 efficiency in other organs and tissues and the use of CRISPR/Cas9 in tumor-prone backgrounds.
In this study the researchers delivered the genes necessary for CRISPR through injections into veins in the tails of the mice.
While this is an effective way to get genetic material to the liver it would not work for other organs of interest.
However nanoparticles and other delivery methods now being developed for DNA and RNA could prove more effective in targeting other organs Sharp says.
The research was funded by the National institutes of health and the National Cancer Institute u
#New material structures bend like microscopic hair MIT engineers have fabricated a new elastic material coated with microscopic hairlike structures that tilt in response to a magnetic field.
Depending on the field s orientation the microhairs can tilt to form a path through which fluid can flow;
The researchers fabricated an array of the microhairs onto an elastic transparent layer of silicone.
but also light much as window blinds tilt to filter the sun. Researchers say the work could lead to waterproofing and anti-glare applications such as smart windows for buildings and cars.
You could coat this on your car windshield to manipulate rain or sunlight says Yangying Zhu a graduate student in MIT s Department of Mechanical engineering.
So you could filter how much solar radiation you want coming in and also shed raindrops. This is an opportunity for the future.
In the near term the material could also be embedded in lab-on-a-chip devices to magnetically direct the flow of cells and other biological material through a diagnostic chip s microchannels.
The paper s co-authors are Evelyn Wang an associate professor of mechanical engineering former graduate student Rong Xiao and postdoc Dion Antao.
For example human nasal passages are lined with cilia small hairs that sway back and forth to remove dust and other foreign particles.
Zhu chose to work with materials that move in response to a magnetic field. Others have designed such magnetically actuated materials by infusing polymers with magnetic particles.
However Wang says it s difficult to control the distribution and therefore the movement of particles through a polymer.
MIT engineers show their magnetic microhairs in action. Video: Melanie Gonick/MIT Instead she and Zhu chose to manufacture an array of microscopic pillars that uniformly tilt in response to a magnetic field.
To do so they first created molds which they electroplated with nickel. They then stripped the molds away
and bonded the nickel pillars to a soft transparent layer of silicone. The researchers exposed the material to an external magnetic field placing it between two large magnets
and found they were able to control the angle and direction of the pillars which tilted toward the angle of the magnetic field.
We can apply the field in any direction and the pillars will follow the field in real time Zhu says.
Tilting toward a fieldin experiments the team piped a water solution through a syringe and onto the microhair array.
Under a magnetic field the liquid only flowed in the direction in which the pillars tilted
when the researchers stood the array against a wall: Through a combination of surface tension and tilting pillars water climbed up the array following the direction of the pillars.
Since the material s underlying silicone layer is transparent the group also explored the array s effect on light.
Zhu shone a laser through the material while tilting the pillars at various angles and found she could control how much light passed through based on the angle at which the pillars bent.
In principle she says more complex magnetic fields could be designed to create intricate tilting patterns throughout an array.
Such patterns may be useful in directing cells through a microchip s channels or wicking moisture from a windshield.
Or depending on how you design the magnetic field you could get the pillars to close in like a flower.
This research was supported by funding from the Air force Office of Scientific research r
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