Cornell University 3D Microchannel Networks Using Sacrificial Sugar Structures
Advisor: Harold Craighead
At a symposium that Leon Bellan once attended, a speaker said that an obstacle in the field of tissue engineering research is obtaining materials that mimic capillaries in living tissue. Pondering that matter, Bellan wondered if he could apply principles from his own work in electrospinning, where an electric field works to transform a polymer solution into long nanofiber strands. He realized that if he could spin a mat of fibers out of an easily soluble substance, coat the mat with polymer, then dissolve away the fibers, he could be left with a mass that had a capillary-like network that would allow blood to flow through it.
He knew that electrospun fibers wouldn’t work, partly because they would be far too thin to accommodate the flow of blood. Thinking about what fibers might exist that could be made thicker, were nontoxic, cheap, and easily dissolved, Bellan had a thought—cotton candy. Purchasing a cotton candy machine, Bellan spun a wad of cotton candy in the lab, covered it with liquid polymer, let the polymer solidify, then soaked it in water to dissolve the sugar. He found himself with what he wanted, a material containing an interconnected network of tiny capillary-sized tubes.
Bellan, 28, who received his Ph.D. in applied engineering and physics in 2008, is interested in using his technique to construct artificial tissues that have an embedded vascular system, although he is prepared to investigate other applications. He is currently conducting postdoctoral research in Robert Langer’s lab at MIT, where well-known tissue-engineering research has taken place.
Originally from Pasadena, California, Bellan always wanted to be an experimental scientist because, as he says, “Experimental scientists get to play with toys.” He also acknowledges the influence of his parents, one a professor at Caltech and the other a research scientist at NASA’s JPL, as influencing his own interest in science and engineering.
Duke University Wickless Vapor Chamber Enabled by Jumping Drops
Advisor: Chuan-Hua Chen
Jonathan Boreyko was a student in advisor Chuan-Hua Chen’s lab when he decided to investigate a curious phenomenon that his advisor had mentioned. Water drops condensing on a superhydrophobic (ultra water repellent) surface behaved oddly, mysteriously and instantaneously disappearing as they formed despite the fact that the surface was horizontally oriented. Boreyko set up a microscope with a high-speed video camera over the superhydrophobic surface so that he could observe the rapidly moving drops. The high-speed movies revealed that the drops mobilized whenever they coalesced together, and noticing that these moving drops became blurry to the microscope led to his insight that they were likely jumping completely off the surface. So he set up a microscope and the high-speed camera beside, rather than above, the superhydrophobic surface to capture the jumping motion. It took dozens of attempts before the phenomenon occurred within the limited focal plane of the camera, but eventually Boreyko had videos clearly showing coalescing condensate drops spontaneously leaping off the superhydrophic surface, a few millimeters into the air, without the aid of any gravitational or external forces.
Boreyko shared his discovery with Chen, who mused that such behavior might be useful in a vapor chamber, a device similar to a heat pipe widely used for cooling computer chips. Normally, one side of the chamber is attached to a heat-producing chip while the other end is surrounded by metal fins serving as a heat sink. Water inside of the chamber evaporates from the heated end, carrying a great deal of heat energy with it. When the water reaches the cool side of the chamber, it condenses, and releases the heat through the fins. In standard vapor chambers, a wick coating trickles the condensed fluid back to the hot end of the chamber where it can repeat its work. Boreyko, however, designed a chamber in which the condensing water jumps off a superhydrophobic surface directly back to the computer chip, completely removing the thermal resistance of the wicked structure currently placed between the chip and the water. His jumping drops work more quickly than a wick and allow the water to evaporate directly off the backside of the computer chip, allowing for greater and more efficient heat transfer; in fact, Boreyko envisions a chamber that has the potential to be ten times more efficient for microelectronics cooling than the chambers now in use.
Originally from Chapel Hill, North Carolina, Boreyko, 24, is pursuing his doctorate in mechanical engineering close to home at Duke. He recalls that as a youngster, he was always drawn to technology and engineering and was enamored with anything that had buttons or a video screen. In addition, he remembers always being involved with water, from early swim lessons to lifeguarding to playing water polo. He reasons, “All of these experiences probably explain my attraction toward engineering and fluid mechanics.”
Weston Daniel and David Giljohann Northwestern University Synthetic HDL
Advisors: Chad Mirkin and C. Shad Thaxton
Weston Daniel and David Giljohann present gold nanoparticles that mimic the size, structure, and activity of naturally-occurring high density lipoproteins—or HDL, often referred to as “good cholesterol.” Having a high ratio of HDL to LDL (low density lipoproteins, or “bad cholesterol”) in the bloodstream is associated with a lower risk of atherosclerosis—the buildup of clog-forming plaque along artery walls that is a major contributor to heart disease and stroke.
Daniel and Giljohann hope that their synthetic HDL may lead to a pharmaceutical in which patients take the nanoparticle in pill form, and the synthetic HDL augments the natural HDL supply in a patient’s bloodstream. If this can be achieved, the synthetic HDL might fill an important therapeutic gap in the prevention and treatment of heart disease. Existing cholesterol drugs act mainly to reduce LDL. Lowering LDL has indeed proven to be of substantial medical value, but the ability to raise HDL has been widely seen as a critical need.
So far, however, drugs that raise HDL have met only limited success, as have approaches to raise HDL with lifestyle or dietary changes. However, in mouse tests, the team demonstrated that their synthetic HDL behaves much like the natural form, in that it floats around the bloodstream, scavenges cholesterol, drops it in the liver and adrenal glands, and heads out empty handed to look for more.
Daniel and Giljohann have as one of their advisors C. Shad Thaxton, a 2001 Collegiate Inventors Competition winner.
From Burnsville, Minnesota, Daniel, 26, received an undergraduate degree from the University of Minnesota and is currently working on his Ph.D. in chemistry. He was drawn to chemistry because it seemed tangible to him, and he remembers, “I find it fascinating that a seemingly small change in a molecule can dramatically change its properties.” He looks forward to continuing his work in nanoscience, including with synthetic HDL.
Giljohann, 28, who is working on his Ph.D. in biological sciences, received his undergraduate degree in the same field of study from Northwestern. Originally from Elm Grove, Wisconsin, he notes, “I always wanted to be a researcher in some capacity. For awhile, I wanted to explore the world’s oceans. I remember designing amphibious vehicles that would take me from land to under the sea.” Today he is a co-founder of AuraSense, a start up company that will work to commercialize the HDL technology.
Geoffrey von Maltzahn
Massachusetts Institute of Technology Nanoparticles that Communicate to Amplify Drug and Imaging Agent Targeting to Disease
Advisor: Sangeeta Bhatia
Geoffrey von Maltzahn turns what may be a new page in nanomedicine with his method of using a pair of nanoparticles that work together in an innovative way to increase the effectiveness and lower the side effects of existing cancer drugs. In his approach, one set of nanoparticles lodges in tumors and generates numerous targets for a second set of nanoparticles that deliver anti-cancer drugs. This process of signal amplification differs from traditional combination therapies and may make it possible to target such drugs much more directly than currently possible, potentially allowing higher doses to reach tumors while sparing healthy cells.
Powerful cancer-killing drugs are well-known to science and widely used in clinical medicine, but since these drugs are also highly toxic to healthy cells, targeting drugs specifically to tumors has been a major focus in cancer research. Of late, much of this drug-targeting research has looked at using nanoparticles to carry the drugs to tumors. A major challenge, however, is that cancer cells, and the tumors they may form, have finite numbers of targets to which nanoparticles can attach—and since a given nanoparticle can carry only a small drug payload, this limits the amount of drug that can be delivered.
Tumors have a high demand for nutrients and oxygen, and as a result have many blood vessels supplying them. Von Maltzahn’s first nanoparticle targets the tumor blood vessels and in doing so, causes local bleeding. The bleeding prompts the body to turn on clotting factors in the area. Then, the second nanoparticle comes in, programmed to be attracted to the activated clotting factors, and delivers a cancer drug. Since the body responds to an even small amount of bleeding with a flood of clotting factors, this process dramatically increases the number of targets for the drug-carrying particles. In essence, the first nanoparticles find the tumors and then recruit the second nanoparticlesfrom circulation by harnessing a natural chain reaction.
Von Maltzahn has compelling data demonstrating efficacy in mouse experiments, and hopes to continue refining his approach to make it particularly effective in delivering drugs to patients with highly metatastic cancers, and other diseases.
Raised first in Arlington, Texas and then Fairfax, Virginia, von Maltzahn, 29, received degrees from both MIT and the University of California, San Diego before beginning his current work on a Ph.D. in medical engineering and physics. He was influenced when he was young by his interest in art and his observations of the natural world around him. He says, “It was a fun process of observation, interpretation, and creation. Today, I use many of the same processes in the medium of biologically-inspired engineering.”
Harvard Medical School Mulitplex Automated Genome Engineering (MAGE) for Renewable Chemicals, Fuels, and Therapeutics
Advisors: George Church and Farren Isaacs
Harris Wang was a student in the lab of George Church, a researcher well-known in the world of genetic sequencing for his attempts to make genetic sequencing faster and cheaper. Church was long interested in creating faster tools for cell programming, and discovered that Wang was willing to take on the challenge. Wang knew that cell programming was still a slow and hands-on process. So he developed a protocol designed to permit faster cell programming, and then put together hardware and software to automate it. He calls the approach MAGE: Multiplex Automated Genome Engineering.
To demonstrate, Wang engineered a strain of E. coli bacterium that produces lycopene—a red-colored antioxidant, abundant in tomatoes and that may be linked to reduced rates of prostate cancer. Wang added the genetic recipe for lycopene to the bacterium’s chromosome. Then he used his MAGE approach to evolve a strain of the bacteria in which production of lycopene was highly efficient. In a more traditional approach, researchers painstakingly isolate, snip apart, reassemble, and reinsert individual genes.
Wang, on the other hand, quickly produced billions of mutations—far more than he would have had time to create by hand. Wang believes that his technology will allow bioengineers to produce customized microorganisms much more cheaply and quickly than possible before. Such engineered microorganisms might be used to produce a wide variety of useful compounds, such as antibiotics, biofuels, and chemotherapy drugs.
Wang, 26, is currently working towards his doctorate in biophysics. Born in Beijing, Wang moved with his family to the U.S. at age nine and grew up in Salt Lake City. He remembers as a child when his aunt made him write out thousands of Chinese calligraphy characters. If he thought about writing a thousand characters, it was daunting, but if he thought about writing characters in sets of ten, then it wasn’t. He says, “Science is often this way, too. We may look at a big scientific challenge and get intimidated by the size, scale, and scope, but if we boil it down into smaller components, then we can make progress in a reasonable manner.”
Yuehua (Tony) Yu Rensselaer Polytechnic Institute Highly Controllable Binary Guanosine Gels for Nano and Biotechnology
Advisor: Linda McGown
Early in 2005, Tony Yu was working with guanosines, essential compounds of cellular and metabolic activity that occur naturally in living systems. Yu was investigating the gelatin like properties the compounds take on when mixed with water. He prepared for an experiment by mixing two guanosines with markedly different levels of water solubility together and since it was time to go home for the night, stored his flask of gel-like material in the lab refrigerator. The next day, to his surprise, he discovered that his guanosine mixture had turned to liquid. Yu set the materials aside on his lab bench. In an even bigger surprise, Yu found that after the material warmed up, they reformed into a gel. The material he had mixed was behaving in a manner opposite that of most substances—it was melting when cold and freezing when warm.
Yu conducted additional tests and found the effect was consistent and repeatable. Soon, he began to think that if he could make the gel-liquid transitions highly controllable and adjustable, he might have something very useful. This might be a tool—long sought in his lab and industry-wide—to handle, hold, and separate small particles easily, inexpensively, and gently. Such particles, including nanomaterials and proteins useful for research, medicine, and industry, are often notoriously difficult to handle because they clump together in solution.
Yu continued to study binary G-gels (gels that contain two forms of guanosine) and learned to intricately tune their behavior based on the ratio of guanosine compounds, the pH, and other factors. He has also demonstrated a number of practical applications for his G-gels which include the ability to sort, align, and put into solution bulk quantities of single walled carbon nanotubes. In another approach, the liquid gel carries the nanoparticles where needed, and is then warmed up to solidify—thus placing or activating specific nanoparticles. Afterward, dropping the temperature again allows the gel to turn back to liquid, and be drained off. Yu has demonstrated additional features achievable with the G-gels that appear very promising.
Yu, 30, received his B.S. and M.S. degrees from Nankai University in China and received his Ph.D. in chemistry in 2009. Raised in China, Yu initially didn’t choose chemistry as his field of study. However, he says, “I got a high score in chemistry in my entrance exam, and the college put me there because they thought I would fit in.” Soon after he started researching, he realized he enjoyed chemistry and the hard work, thought, learning, and imagination involved with it.
University of Illinois at Urbana-Champaign The Drop Point
Advisor: Deana McDonagh
Stephen Diebold presents an improved pointing stick for use by people with quadriplegia and other disabilities that prevent them from using their arms. Pointing sticks are used to type, operate cell phones, and otherwise manipulate objects. Existing pointing sticks are gripped in the user's teeth or mounted, helmet-like, on the user's head. Either approach presents problems: a mouth-held pointer prevents the user from speaking and a head-mounted pointer requires assistance to put on or take off.
Diebold's pointing stick is designed to be donned and doffed with a shrug of the user's chin. He came up with the approach after spending time with then law-student Jonathan Ko, who has quadriplegia. Diebold said, “I saw that to Jonathan, the pointing stick was his arms and hands, and he had to ask somebody every time he wanted to use his hands—that seemed absurd to me.” By attaching the pointing stick to a cup which is in turn attached to a strap that loops around the user’s neck, the user is able to freely engage the pointer as he wishes.
A native of the Chicago suburb Rolling Meadows and a graduate of William Fremd High School, Diebold, 21, is now majoring in industrial design. He finds himself drawn to the field for its blend of research and art, since products must not just be functional but also able to instill enjoyment and pride in the user. Upon his graduation, if Diebold doesn’t find himself a part of the industrial design field, he will be pursuing computer animation to focus on rendering products or architecture interiors. For the moment, he’s proud of the fact that he has a U.S. patent pending for his design of The Drop Point.
Cornell University Skull Base Sealer
Advisor: David Lipson
As part of an anthropology class, Mark Levatich spent ten days shadowing doctors in operating rooms. He chose to watch neurosurgeons, and became interested in an endoscopic procedure that operated on the area surrounding the pituitary gland, which sits near the base of the skull.
Many such procedures are done endoscopically through the nasal passages, and it was just such a nasal endoscopy that Levatich witnessed. But as he watched, he realized that there were issues with closing the surgical opening in the skull. In some cases, efforts to close the hole took longer than the actual operation. The approach Levatich watched involves using forceps to place pieces of fat grafted from the patient and surgical foam into the hole in the skull. With luck, soft tissue grows over this foam and forms a seal. But too often, the seal is imperfect, and cerebrospinal fluid leaks out, requiring later surgical repair.
Levatich wanted to create a tool that would be faster and easier for surgeons and better for the patient. His prototype permits the use of standard bone cement, which replaces the surgically removed bone, instead of foam to fill the hole in the skull. Levatich says his device overcomes two problems that have kept bone cement from being used before in this way: It prevents the heat released as bone cement cures from damaging the brain and nasal tissues, and holds the cement in the proper position while it cures. His prototype consists of a single tube packed to deploy a protective pad of foam against the brain, followed by a plastic self-sealing sheet as a mold. Bone cement is then injected between the pad and the mold. The mold not only holds the bone cement in place while it cures, but acts as a water-proof barrier to insulate the cement so that while it cures, cooling water can be circulated through the nasal area. Levatich says that the surgeon whose procedures he originally observed has already asked him how soon he could obtain the device.
An undergraduate at Cornell who is also a native of Ithaca, Levatich ,22, is majoring in biological engineering and biological sciences, fascinated with the merger between biology and inventive design. Always inquisitive, Levatich is a serial inventor and spends the majority of his time applying his current coursework to design solutions to a diverse set of problems ranging from pharmaceuticals to social psychological profiling. In terms of the future, Levatich says, “I hope to start my own company to house my patents and finance the creation of my inventions while I continue on to a Masters of Engineering, medical school, and an MBA.”
Philip Wagner, Lindsay Holiday, and Dana Leland Dartmouth College Household Electrocoagulation Arsenic Filter
Advisor: Douglas Van Citters
As part of a capstone design course for Dartmouth’s engineering program, Phil Wagner, Lindsay Holiday, and Dana Leland tackled a problem: to reduce arsenic found in groundwater to safe levels, with a cheap, reliable device made of materials locally available in rural Nepal.
Arsenic naturally leaches out of the rock underlying much of Nepal, so the groundwater there typically contains up to 200 parts per billion (ppb) of arsenic. The World Health Organization (WHO) standards for drinking water call for no more than 10 ppb arsenic, and WHO considers arsenic in drinking water an “urgent problem” in Nepal and neighboring areas.
The team developed a way of using electrocoagulation—a process employed in the large-scale water treatment plants of many modern cities—in a system radically downsized to fit into three five-gallon buckets. Water to be treated goes into the first bucket where the students induce electrocoagulation by sending a simple electric current through two steel plates in the water. Iron precipitates are released. These iron particles bond aggressively with the arsenic that exists in the water. This newly-reacted water is then poured into a second bucket of clean sand, which has a hole in the bottom and sits over a third empty bucket. The sand collects the iron-arsenic particles and arsenic-free water collects in the bottom bucket. When the team tested the device with water contaminated with 200 ppb arsenic, the output water contained under 1ppb arsenic—well under the 10 ppb level considered safe for drinking.
Wagner, 22, who grew up in Fogelsville, Pennsylvania and graduated in Spring 2009 with his engineering degree, is currently spending a year teaching high school in the Marshall Islands. Upon his return to the U.S., Wagner plans to continue graduate studies in engineering. As he says, “Engineering balances both a science aspect and a human aspect, which makes it endlessly interesting.”
Holiday, 24, spent time growing up in both Teec Nos Pos, Arizona in the Navajo Nation and Phoenix. As a recent environmental engineering graduate, she looks forward to her immediate work with the Energy Efficiency Division of Southern California Edison. Looking forward several years into the future, Holiday says, “I would like to own a business on the Navajo Nation and encourage building sustainable communities.”
Also a recent environmental engineering graduate and a Baltimore native, Leland, 22, is now a project manager at Eaton Corporation in Wisconsin, participating in a fast-track leadership program. Leland found work on the capstone engineering project very rewarding, commenting, “I hope our work can help bring clean drinking water to people in need in third world nations such as Nepal, Bangladesh, and Cambodia.”
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