Dialysis Membrane Made From Graphene

Dialysis, in the most general sense, is the process by which molecules filter out of one solution, by diffusing through a membrane, into a more dilute solution. Outside of hemodialysis, which removes waste from blood, scientists use dialysis to purify drugs, remove residue from chemical solutions, and isolate molecules for medical diagnosis, typically by allowing the materials to pass through a porous membrane.

Today’s commercial dialysis membranes separate molecules slowly, in part due to their makeup: They are relatively thick, and the pores that tunnel through such dense membranes do so in winding paths, making it difficult for target molecules to quickly pass through.

Now MIT engineers have fabricated a functional dialysis membrane from a sheet of graphene — a single layer of carbon atoms, linked end to end in hexagonal configuration like that of chicken wire. The graphene membrane, about the size of a fingernail, is less than 1 nanometer thick. (The thinnest existing memranes are about 20 nanometers thick.) The team’s membrane is able to filter out nanometer-sized molecules from aqueous solutions up to 10 times faster than state-of-the-art membranes, with the graphene itself being up to 100 times faster.

While graphene has largely been explored for applications in electronics, Piran Kidambi, a postdoc in MIT’s Department of Mechanical Engineering, says the team’s findings demonstrate that graphene may improve membrane technology, particularly for lab-scale separation processes and potentially for hemodialysis.

Because graphene is so thin, diffusion across it will be extremely fast,” Kidambi says. “A molecule doesn’t have to do this tedious job of going through all these tortuous pores in a thick membrane before exiting the other side. Moving graphene into this regime of biological separation is very exciting.”

Kidambi is a lead author of a study reporting the technology, published today in Advanced Materials. Six co-authors are from MIT, including Rohit Karnik, associate professor of mechanical engineering, and Jing Kong, associate professor of electrical engineering.

Source: http://news.mit.edu/

Artificial Intelligence Writes Code By Looting

Artificial intelligence (AI) has taught itself to create its own encryption and produced its own universal ‘language. Now it’s writing its own code using similar techniques to humans. A neural network, called DeepCoder, developed by Microsoft and University of Cambridge computer scientists, has learnt how to write programs without a prior knowledge of code.  DeepCoder solved basic challenges of the kind set by programming competitions. This kind of approach could make it much easier for people to build simple programs without knowing how to write code.

deep coder

All of a sudden people could be so much more productive,” says Armando Solar-Lezama at the Massachusetts Institute of Technology, who was not involved in the work. “They could build systems that it [would be] impossible to build before.”

Ultimately, the approach could allow non-coders to simply describe an idea for a program and let the system build it, says Marc Brockschmidt, one of DeepCoder’s creators at Microsoft Research in Cambridge. UK.DeepCoder uses a technique called program synthesis: creating new programs by piecing together lines of code taken from existing software – just like a programmer might. Given a list of inputs and outputs for each code fragment, DeepCoder learned which pieces of code were needed to achieve the desired result overall.

Source: https://www.newscientist.com/

New Material Ten Times Stronger Than Steel, Designed From Graphene

A team of researchers at MIT has designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon. The new material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel. In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.

The new findings show that the crucial aspect of the new 3-D forms has more to do with their unusual geometrical configuration than with the material itself, which suggests that similar strong, lightweight materials could be made from a variety of materials by creating similar geometric features.

graphene material

The team was able to compress small flakes of graphene using a combination of heat and pressure. This process produced a strong, stable structure whose form resembles that of some corals and microscopic creatures called diatoms. These shapes, which have an enormous surface area in proportion to their volume, proved to be remarkably strong. “Once we created these 3-D structures, we wanted to see what’s the limit — what’s the strongest possible material we can produce,” says Zhao Qin, research scientist at MIT. To do that, they created a variety of 3-D models and then subjected them to various tests. In computational simulations, which mimic the loading conditions in the tensile and compression tests performed in a tensile loading machine, “one of our samples has 5 percent the density of steel, but 10 times the strength,” Qin says.
The findings have been reported in the journal Science Advances.

Source: http://news.mit.edu/

How To Safely Use Graphene Implants Into Tissues

In the future, our health may be monitored and maintained by tiny sensors and drug dispensers, deployed within the body and made from grapheneone of the strongest, lightest materials in the world. Graphene is composed of a single sheet of carbon atoms, linked together like razor-thin chicken wire, and its properties may be tuned in countless ways, making it a versatile material for tiny, next-generation implants. But graphene is incredibly stiff, whereas biological tissue is soft. Because of this, any power applied to operate a graphene implant could precipitously heat up and fry surrounding cells.

Now, engineers from MIT and Tsinghua University in Beijing have precisely simulated how electrical power may generate heat between a single layer of graphene and a simple cell membrane. While direct contact between the two layers inevitably overheats and kills the cell, the researchers found they could prevent this effect with a very thin, in-between layer of water. By tuning the thickness of this intermediate water layer, the researchers could carefully control the amount of heat transferred between graphene and biological tissue. They also identified the critical power to apply to the graphene layer, without frying the cell membrane.

Co-author Zhao Qin, a research scientist in MIT’s Department of Civil and Environmental Engineering (CEE), says the team’s simulations may help guide the development of graphene implants and their optimal power requirements.


We’ve provided a lot of insight, like what’s the critical power we can accept that will not fry the cell,” Qin says. “But sometimes we might want to intentionally increase the temperature, because for some biomedical applications, we want to kill cells like cancer cells. This work can also be used as guidance [for those efforts.

Qin’s co-authors include Markus Buehler, head of CEE and the McAfee Professor of Engineering, along with Yanlei Wang and Zhiping Xu of Tsinghua University.
The results are published today in the journal Nature Communications.

Source: http://news.mit.edu/

Vaccine That Is Programmable In One Week

MIT engineers have developed a new type of easily customizable vaccine that can be manufactured in one week, allowing it to be rapidly deployed in response to disease outbreaks. So far, they have designed vaccines against Ebola, H1N1 influenza, and Toxoplasma gondii (a relative of the parasite that causes malaria), which were 100 percent effective in tests in mice. The vaccine consists of strands of genetic material known as messenger RNA, which can be designed to code for any viral, bacterial, or parasitic protein. These molecules are then packaged into a molecule that delivers the RNA into cells, where it is translated into proteins that provoke an immune response from the host.

In addition to targeting infectious diseases, the researchers are using this approach to create cancer vaccines that would teach the immune system to recognize and destroy tumors.

MIT-Program-Vaccines_0 (1)

This nanoformulation approach allows us to make vaccines against new diseases in only seven days, allowing the potential to deal with sudden outbreaks or make rapid modifications and improvements,” says Daniel Anderson, an associate professor in MIT’s Department of Chemical Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

Anderson is the senior author of a paper describing the new vaccines in the Proceedings of the National Academy of Sciences. The project was led by Jasdave Chahal, a postdoc at MIT’s Whitehead Institute for Biomedical Research, and Omar Khan, a postdoc at the Koch Institute; both are the first authors of the paper.

Source: http://news.mit.edu/

How To Map RNA Molecules In The Brain

Cells contain thousands of messenger RNA molecules, which carry copies of DNA’s genetic instructions to the rest of the cell. MIT engineers have now developed a way to visualize these molecules in higher resolution than previously possible in intact tissues, allowing researchers to precisely map the location of RNA throughout cells. Key to the new technique is expanding the tissue before imaging it. By making the sample physically larger, it can be imaged with very high resolution using ordinary microscopes commonly found in research labs.

MIT RNA-Imaging

Now we can image RNA with great spatial precision, thanks to the expansion process, and we also can do it more easily in large intact tissues,” says Ed Boyden, an associate professor of biological engineering and brain and cognitive sciences at MIT, a member of MIT’s Media Lab and McGovern Institute for Brain Research, and the senior author of a paper describing the technique in the July 4 issue of Nature Methods.

Studying the distribution of RNA inside cells could help scientists learn more about how cells control their gene expression and could also allow them to investigate diseases thought to be caused by failure of RNA to move to the correct location.

Source: http://news.mit.edu/

Bones and Shells, Inspiration For New Materials

Researchers at MIT are seeking to redesign concrete — the most widely used human-made material in the world — by following nature’s blueprints. In a paper published online in the journal Construction and Building Materials, the team contrasts cement pasteconcrete’s binding ingredient — with the structure and properties of natural materials such as bones, shells, and deep-sea sponges. As the researchers observed, these biological materials are exceptionally strong and durable, thanks in part to their precise assembly of structures at multiple length scales, from the molecular to the macro, or visible, level.

From their observations, the team, led by Oral Buyukozturk, a professor in MIT’s Department of Civil and Environmental Engineering (CEE), proposed a new bioinspired, “bottom-upapproach for designing cement paste.

bones molecular structure

These materials are assembled in a fascinating fashion, with simple constituents arranging in complex geometric configurations that are beautiful to observe,” Buyukozturk says. “We want to see what kinds of micromechanisms exist within them that provide such superior properties, and how we can adopt a similar building-block-based approach for concrete.”

Ultimately, the team hopes to identify materials in nature that may be used as sustainable and longer-lasting alternatives to Portland cement, which requires a huge amount of energy to manufacture. “If we can replace cement, partially or totally, with some other materials that may be readily and amply available in nature, we can meet our objectives for sustainability,” Buyukozturk says.

Source: http://news.mit.edu/2016/

Obesity: How To Burn Fat

Researchers at MIT and Brigham and Women’s Hospital have developed nanoparticles that can deliver antiobesity drugs directly to fat tissue. Overweight mice treated with these nanoparticles lost 10 percent of their body weight over 25 days, without showing any negative side effects. The drugs work by transforming white adipose tissue, which is made of fat-storing cells, into brown adipose tissue, which burns fat. The drugs also stimulate the growth of new blood vessels in fat tissue, which positively reinforces the nanoparticle targeting and aids in the white-to-brown transformation. These drugs, which are not FDA-approved to treat obesity, are not new, but the research team developed a new way to deliver them so that they accumulate in fatty tissues, helping to avoid unwanted side effects in other parts of the body.


The advantage here is now you have a way of targeting it to a particular area and not giving the body systemic effects. You can get the positive effects that you’d want in terms of antiobesity but not the negative ones that sometimes occur,” says Robert Langer, the David H. Koch Institute Professor at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research.

More than one-third of Americans are considered to be obese, and last year obesity overtook smoking as the top preventable cause of cancer death in the United States, with 20 percent of the 600,000 cancer deaths attributed to obesity.

Langer and Omid Farokhzad, director of the Laboratory of Nanomedicine and Biomaterials at Brigham and Women’s Hospital, are the senior authors of the study, which appears in theProceedings of the National Academy of Sciences the week of May 2. The paper’s lead authors are former MIT postdoc Yuan Xue and former BWH postdoc Xiaoyang Xu.

Source: http://news.mit.edu/

Super Smart Band-Aids

This is what a band-aid in the future might look like. It’s a stretchable hydrogel that in many ways mimics
the properties of human tissue.

smart band-aid

Hydrogel is a polymer network infiltrated with water. Even though it is only 5 to 10 percent polymer, this network is extremely important“, says Xuanhe Zhao, Professor of Mechanical engineering at the Massachusetts Institute of Technology (MIT).

Important because the polymer makes up a microscopic scaffold that endows it with special properties uncommon to synthetic hydrogels. It is highly stretchable and can adhere easily to surfaces. Most importantly, it is specifically designed to be compatible with the human body – both inside and out. That compatibility could potentially give rise to a new class of biomedical devices.

We further embed electronic devices such as sensors, such as different drug delivery devices into this matrix to achieve what we call the smart applications“, comments Zhao.  Applications that could turn an ordinary band-aid into a tool to actively monitor and heal wounds autonomously. Zhao uses burns as an example… “Once the sensor senses an abnormal increase in temperature for example It will send out a command. Then the controlled drug delivery system can deliver a specific drug to that specific location“, he adds. The researchers are now fine tuning the properties and functionality of their hydrogels. They hope that soon healing everything from a scratch to an ulcer will be as simpleas putting on a band-aid.

Source: http://www.reuters.com/

Yarns that store and release electrical power

Wearable electronic devices for health and fitness monitoring are a rapidly growing area of consumer electronics; one of their biggest limitations is the capacity of their tiny batteries to deliver enough power to transmit data. Now, researchers at MIT and in Canada have found a promising new approach to delivering the short but intense bursts of power needed by such small devices. The key is a new approach to making supercapacitors — devices that can store and release electrical power in such bursts, which are needed for brief transmissions of data from wearable devices such as heart-rate monitors, computers, or smartphones, the researchers say. They may also be useful for other applications where high power is needed in small volumes, such as autonomous microrobots.

The new approach uses yarns, made from nanowires of the element niobium, as the electrodes in tiny supercapacitors (which are essentially pairs of electrically conducting fibers with an insulator between). The concept is described in a paper in the journal ACS Applied Materials and Interfaces by MIT professor of mechanical engineering Ian W. Hunter, doctoral student Seyed M. Mirvakili, and three others at the University of British Columbia.

Nanotechnology researchers have been working to increase the performance of supercapacitors for the past decade. Among nanomaterials, carbon-based nanoparticles — such as carbon nanotubes and graphene — have shown promising results, but they suffer from relatively low electrical conductivity, Mirvakili says.

In this new work, he and his colleagues have shown that desirable characteristics for such devices, such as high power density, are not unique to carbon-based nanoparticles, and that niobium nanowire yarn is a promising an alternative.

MIT-Nanowires-1Yarn made of niobium nanowires, seen here in a scanning electron microscope image (background), can be used to make very efficient supercapacitors, MIT researchers have found. Adding a coating of a conductive polymer to the yarn (shown in pink, inset) further increases the capacitor’s charge capacity. Positive and negative ions in the material are depicted as blue and red spheres.

Imagine you’ve got some kind of wearable health-monitoring system,” Hunter says, “and it needs to broadcast data, for example using Wi-Fi, over a long distance.” At the moment, the coin-sized batteries used in many small electronic devices have very limited ability to deliver a lot of power at once, which is what such data transmissions need.

Long-distance Wi-Fi requires a fair amount of power,” says Hunter, the George N. Hatsopoulos Professor in Thermodynamics in MIT’s Department of Mechanical Engineering, “but it may not be needed for very long.” Small batteries are generally poorly suited for such power needs, he adds.

We know it’s a problem experienced by a number of companies in the health-monitoring or exercise-monitoring space. So an alternative is to go to a combination of a battery and a capacitor,” Hunter says: the battery for long-term, low-power functions, and the capacitor for short bursts of high power. Such a combination should be able to either increase the range of the device, or — perhaps more important in the marketplace — to significantly reduce size requirements.

Source: https://newsoffice.mit.edu/

Artificial Protein Carries Atoms Across Membranes

Human cells are protected by a largely impenetrable molecular membrane. Now Gevorg Grigoryan, an assistant professor of computer science at Dartmouth College, and researchers from other institutions have built the first artificial transporter protein that carries individual atoms across membranes, opening the possibility of engineering a new class of smart molecules with applications in fields as wide ranging as nanotechnology and medicine.

transport protein 2
Each human cell is surrounded by a lipid membrane, a molecular barrier that serves to contain the cellular machinery and protect it from the surrounding elements. This cellular “skin” is impenetrable to most biological molecules but also presents a conundrum: if chemicals can’t get in or out, how is a cell to receive nutrients (food) and remove unwanted products of metabolism (trash)?

Nature has come up with an elegant solution to this logistical problem — transporter proteins (or transporters). These molecular machines are embedded in the cellular membrane and serve as gatekeepers, allowing specific chemicals to shuttle in and out when needed. Though biologists have known about transporters for many decades, their precise mechanism of action has been elusive.

The study, which has been published in the journal Science, is a milestone in designing and understanding membrane proteins (a PDF is available upon request). The study was conducted by researchers from Dartmouth College, the University of California-San Francisco, Massachusetts Institute of Technology and National Institute of Science Educational and Research in India.

Source: http://www.eurekalert.org/

How To Detect Pancreatic Cancer Years Before

Treating Cancer at very early stage is crucial to prevent a deadly end. This is especially true with the pancreatic cancer. Now biologists from the Massachusetts Institute of Technology ( MIT) have found an early sign of cancer. Years before they show any other signs of disease, pancreatic cancer patients have very high levels of certain amino acids in their bloodstream, according to a new study from MIT, Dana-Farber Cancer Institute, and the Broad Institute.
This finding, which suggests that muscle tissue is broken down in the disease’s earliest stages, could offer new insights into developing early diagnostics for pancreatic cancer, which kills about 40,000 Americans every year and is usually not caught until it is too late to treat.
The study, which appears in the journal Nature Medicine, is based on an analysis of blood samples from 1,500 people participating in long-term health studies. The researchers compared samples from people who were eventually diagnosed with pancreatic cancer and samples from those who were not. The results were dramatic: People with a surge in amino acids known as branched chain amino acids were far more likely to be diagnosed with pancreatic cancer within one to 10 years.
Pancreatic-Cancer_0Pancreatic cancer, even at its very earliest stages, causes breakdown of body protein and deregulated metabolism. What that means for the tumor, and what that means for the health of the patient — those are long-term questions still to be answered,” says Matthew Vander Heiden, an associate professor of biology, a member of MIT’s Koch Institute for Integrative Cancer Research, and one of the paper’s senior authors.
Source: http://newsoffice.mit.edu/