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Friday, March 31st, 2017

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    12:30p
    Stretching the boundaries of neural implants

    Implantable fibers have been an enormous boon to brain research, allowing scientists to stimulate specific targets in the brain and monitor electrical responses. But similar studies in the nerves of the spinal cord, which might ultimately lead to treatments to alleviate spinal cord injuries, have been more difficult to carry out. That’s because the spine flexes and stretches as the body moves, and the relatively stiff, brittle fibers used today could damage the delicate spinal cord tissue.

    Now, researchers have developed a rubber-like fiber that can flex and stretch while simultaneously delivering both optical impulses, for optoelectronic stimulation, and electrical connections, for stimulation and monitoring. The new fibers are described in a paper in the journal Science Advances, by MIT graduate students Chi (Alice) Lu and Seongjun Park, Professor Polina Anikeeva, and eight others at MIT, the University of Washington, and Oxford University.

    “I wanted to create a multimodal interface with mechanical properties compatible with tissues, for neural stimulation and recording,” as a tool for better understanding spinal cord functions, says Lu. But it was essential for the device to be stretchable, because “the spinal cord is not only bending but also stretching during movement.” The obvious choice would be some kind of elastomer, a rubber-like compound, but most of these materials are not adaptable to the process of fiber drawing, which turns a relatively large bundle of materials into a thread that can be narrower than a hair.

    The spinal cord “undergoes stretches of about 12 percent during normal movement,” says Anikeeva, who is the Class of 1942 Career Development Professor in the Department of Materials Science and Engineering. “You don’t even need to get into a ‘downward dog’ [yoga position] to have such changes.” So finding a material that can match that degree of stretchiness could potentially make a big difference to research. “The goal was to mimic the stretchiness and softness and flexibility of the spinal cord,” she says. “You can match the stretchiness with a rubber. But drawing rubber is difficult — most of them just melt,” she says.

    “Eventually, we’d like to be able to use something like this to combat spinal cord injury. But first, we have to have biocompatibility and to be able to withstand the stresses in the spinal cord without causing any damage,” she says.

    The fibers are not only stretchable but also very flexible. “They’re so floppy, you could use them to do sutures, and do light delivery at the same time,” professor Polina Anikeeva says. (Video: Chi (Alice) Lu and Seongjun Park)

    The team combined a newly developed transparent elastomer, which could act as a waveguide for optical signals, and a coating formed of a mesh of silver nanowires, producing a conductive layer for the electrical signals. To process the transparent elastomer, the material was embedded in a polymer cladding that enabled it to be drawn into a fiber that proved to be highly stretchable as well as flexible, Lu says. The cladding is dissolved away after the drawing process.

    After the entire fabrication process, what’s left is the transparent fiber with electrically conductive, stretchy nanowire coatings. “It’s really just a piece of rubber, but conductive,” Anikeeva says. The fiber can stretch by at least 20 to 30 percent without affecting its properties, she says.

    The fibers are not only stretchable but also very flexible. “They’re so floppy, you could use them to do sutures and deliver light  at the same time,” she says.

    “We’re the first to develop something that enables simultaneous electrical recording and optical stimulation in the spinal cords of freely moving mice,” Lu says. “So we hope our work opens up new avenues for neuroscience research.” Scientists doing research on spinal cord injuries or disease usually must use larger animals in their studies, because the larger nerve fibers can withstand the more rigid wires used for stimulus and recording. While mice are generally much easier to study and available in many genetically modified strains, there was previously no technology that allowed them to be used for this type of research, she says.

    “There are many different types of cells in the spinal cord, and we don’t know how the different types respond to recovery, or lack of recovery, after an injury,” she says. These new fibers, the researchers hope, could help to fill in some of those blanks.

    The team included Alexander Derry, Chong Hou, Siyuan Rao, Jeewoo Kang, and professor Yoel Fink at MIT; Tom Richner and professor Chet Mortiz at the University of Washington; and Imogen Brown at Oxford University. The research was supported by the National Science Foundation, the National Institute of Neurological Disorders and Stroke, the U.S. Army Research Laboratory, and the U.S. Army Research Office through the Institute for Soldier Nanotechnologies at MIT.

    2:50p
    The Committee on Animal Care solicits feedback

    The Committee on Animal Care (CAC) and the vice president for research welcome any information that would aid our efforts to assure the humane care of research animals used at MIT and the Whitehead Institute for Biomedical Research.

    Established to ensure that MIT researchers working with animals comply with federal, state, local and institutional regulations on animal care, the CAC inspects animals, animal facilities, and laboratories, and reviews all research and teaching exercises that involve animals before experiments are performed.

    If you have concerns about animal welfare, please contact the Committee on Animal Care (CAC) by calling 617-324-6892, or send your concern in writing to the CAC Office (Room 16-408), or email us at cacpo@mit.edu. The issue will be forwarded to the Chair of the CAC and the Attending Veterinarian.

    You may also contact any of the following:

    All concerns about animal welfare will remain confidential; the identity of individuals who contact the CAC with concerns will be treated as confidential, and individuals will be protected against reprisal and discrimination consistent with MIT policies. The Committee on Animal Care will report its findings and actions to correct the issue to the vice president for research, the director of comparative medicine, the individual who reported the concern (if not reported anonymously), and oversight agencies as applicable.

    3:50p
    Annual CEE research showcase highlights diversity of research across department

    In the Department of Civil and Environmental Engineering (CEE), researchers are constantly looking for new ways to solve some of the world’s most pressing issues. Every year, the department hosts CEE Research Speed Dating Day to encourage community members to think outside the box and to draw inspiration from the research of their peers.

    From developing low-cost sulfur dioxide sensors to creating environmentally friendly human-made materials, the seventh annual event showcased the recent findings and ongoing projects of 50 community members. Undergraduate and graduate students, postdocs, research scientists, and faculty members shared their research through talks and electronic poster sessions.

    Markus J. Buehler, the McAfee Professor of Engineering and head of CEE, welcomed the community to the event. “The event started seven years ago as an idea by a group of faculty who realized the untapped potential of collaboration across the department, and has been wildly successful. Every year it brings together the community; and what is special is that we have presentations from undergraduate students including freshmen, graduate students, postdocs, and faculty,” Buehler said. “It’s a great way to learn about the department, to get inspired, and to consider new ideas or research you haven’t thought about because you heard about a new idea or tool or method.”

    Serguei Saavedra and Tal Cohen, assistant professors of CEE, were the faculty organizers of the 2017 CEE Research Speed Dating Day. Cohen and Saavedra added a judging element with prizes this year, incorporating a competitive element to the event. Throughout the afternoon, faculty judges gave scores for each presentation and poster, and the winners were announced at the end of the night.

    “This event is a clear celebration of the rich diversity of research taking place in CEE,” Saavedra said. 

    Talks demonstrate diversity of CEE research

    CEE research presented at the event ranged from atmospheric chemistry and structural design to transportation and biological communities; but this represents only a sample of the many different types of questions explored in civil and environmental engineering. CEE Research Speed Dating Day was established to provide inspiration and a new perspective that could fuel others' projects. By giving insight into the creative ways researchers approach and solve complex problems, it opens doors for other CEE researchers to consider how they could take similar approaches to their own work.

    The presentation sessions at Research Speed Dating Day demonstrated how current research from across the department is addressing and solving major issues around the world, and how the researchers plan to continue this work in the future.

    Associate professor of CEE Jesse Kroll kicked off the research presentations with his presentation on low-cost sensing for air-quality measurements. Although air quality has drastically improved over the years with Environmental Protection Agency (EPA) standards, air pollution is still a problem. “Air pollution is the single largest environmental risk factor for illness and premature death. The big issue is fine particulate matter [PM]. Outdoor PM pollution accounts for more than 3 million premature deaths per year, and it’s more than double that if you include indoor pollution as well,” he said.

    Kroll pointed out that in the greater Boston area, there are only four air quality monitors. Kroll, graduate student David Hagan, associate department head Professor Colette Heald, and undergraduate students that enroll in 1.091 (Traveling Research Environmental eXperiences: fieldwork) have constructed and deployed low-cost sensors that agree well with official government data in Hawaii. These sensors are not only accurate, but they are much more affordable than the larger monitors. Kroll plans to scale-up the research from Hawaii and study urban areas such as Delhi.

    Caitlin Mueller, assistant professor of CEE and architecture, gave another perspective of the research that CEE faculty members conduct through her presentation on the design and construction of creative structures. Mueller defined creative structures as the combination of ideas from geometry and form with structural engineering. She explained that “the two disciplines related to creative structures are often isolated,” but she studies how to discover new creative structures with her engineering and architecture background. One aspect Mueller and her research team considers when working on creative structures is the environmental impact of the building, from the energy needed to transport materials for its construction to the environmental impact of the building’s use over time.

    Judy “Qingjun” Yang, a graduate student in Professor Heidi Nepf’s lab, shared insight into the mysterious motion of sand. Yang described the value of understanding sediment movement by arguing both that “sand is a great storyteller,” and forms coastlines, but that sand is also a “trouble-maker,” such as in situations where houses are destroyed by coastal erosion. Yang and uses water flumes to test the turbulent kinetic energy for sediment transport, and uses calculated formulas to understand the motion of sand. Looking towards the future, Yang said “I hope to use turbulent kinetic energy models to design better vegetation restoration plains.” 

    To wrap up the research aspect of the night, Cohen presented on solid mechanics. She began her talk by identifying the trend towards soft materials. “Everything around us is becoming softer. We want our cell phones to be flexible, we wish that our robots would handle delicate things, and maybe we can wear our electronics. Essentially, we’re pushing and pulling on materials in ways we weren’t always able and we’re observing phenomena we’ve never observed before,” she said. Cohen’s group looks specifically at how materials respond under dynamic loading conditions, how various material instabilities form and how materials grow. “In the future what I hope my group will be doing is to start to look at the intersections between those three thrusts; essentially trying to understand how maybe growth can induce instability, how materials respond under extreme dynamic loading conditions, and how growing materials behave when they are subjected to extreme conditions,” Cohen said.

    Electronic poster session allows more research spotlights

    The research presentations were separated by two short electronic poster sessions, allowing more community members than ever before to participate in this year’s Research Speed Dating Day.

    E-posters are an environmentally friendly alternative to version of a standard research poster, and they allowed the presenters to have additional graphs and data available to further explain their research.

    Alexa Jaeger, a junior in CEE and earth, atmospheric, and planetary sciences (EAPS), and Amber VanHemel, a sophomore in civil and environmental engineering, presented a poster from data they collected during Traveling Research Environmental eXperiences over Independent Activates Period (IAP). Urged to apply to Research Speed Dating by CEE Assistant Professor Ben Kocar, the pair presented on “UAVs in Precision Agriculture and Low-Cost SO2 Sensors,” also the topic of research in 1.092 (Traveling Research Environmental eXperience (TREX): Fieldwork Analysis and Communication) taught by Kocar and Kroll.    

    “The research has implications for human health, food security, and reducing agriculture-related waste and environmental problems. Obviously, these are all issues that most people care about. It is exciting to be doing research that has a very tangible and relevant goal,” Jaeger said. “We are both really excited about the work we did on TREX and want to tell people about it.”

    Freshmen invited to share their IAP research

    A group of freshmen also attended the event to share the results of their mini-UROP research during the poster session.

    The mini-UROP program is an abbreviated version of the MIT-wide Undergraduate Research Opportunities Program (UROP). A group of 20 freshmen interested in learning about CEE and in getting hands-on experience working in labs enrolled in the CEE mini-UROP class over IAP, and were placed into labs based on their interests.

    The mini-UROP participants and their mentors worked closely together over IAP to conduct research, and on Feb. 3, the mini-UROP students presented their research to their peers and to the CEE community. From there, Cohen personally invited select mini-UROP students to present their findings at Research Speed Dating.

    Diana Nguyen was one student invited. She completed a mini-UROP with CEE graduate student Hayley Gadol in Kocar’s lab. Nguyen extended her research experience beyond IAP into a regular UROP this semester, where she continues to work with Gadol. Nguyen presented a poster on “Microbial Methanogenesis and Sulfate Reduction” at Research Speed Dating.

    “I thought it would be a great opportunity to gain experience in presenting research and to also network with other researchers. My mentor also highly recommended that I try it out,” Nguyen said.

    A CEE tradition

    Every year, Research Speed Dating Day concludes with a dinner reception to encourage community members to network and discuss the research presented earlier in the event. During the reception, Cohen and Saavedra also highlighted presentations and posters that stood out during CEE Research Speed Dating Day. Cohen and Saavedra presented winners of the best presentation, the winners of best undergraduate poster and the best overall poster from each of the two poster sessions. The winners were evaluated by faculty judges and received a certificate and a $250 prize.  

    Graduate student Yongji Wang of the Bourouiba group was presented with the award for best talk for his presentation on drop fragmentation. The winners of the undergraduate poster session were Daly Wettermark and Xin “Florence” Lo. Graduate student Michael Chen of Kocar’s lab won best poster in the first poster session for his presentation of “Pore-scale biogeochemistry: Microfluidic devices and spectroscopic tools.” Joanna Moody, a graduate student in the Regional Transportation Planning and High-Speed Rail Research Group, won the second poster session with her presentation on “High-Speed Rail Market Selection Process for East Japan Railway Company.”

    “With a total of 50 presentations, talks and e-posters combined, the success of this event is a result of an orchestrated effort across the department. It showcased the diverse set of big engineering challenges that our researchers are dealing with while emphasizing the advantages of working together to solve them,” Cohen said.

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