http://nanosapiens.net/2011/12/careers/biotechnology-careers/killer-plants/ http://nanosapiens.net/2011/12/careers/biotechnology-careers/killer-plants/#comments Wed, 07 Dec 2011 18:24:08 +0000 Gabrielle DeMarco http://approach.rpi.edu/?p=2804

The human immune system is a marvelous machine. Bacteria enter the body (perhaps through those nasty, chalky mints at the local diner that you simply could not resist diving in to). Above is a gross image of the mints’ effects as you see salmonella bacteria attacking human tissue. To fight the invasion, our white blood cells immediately get to work to attack the bacteria. If you are lucky, the bacteria are neutralized by the immune system and you can peel yourself off the bathroom floor and move on with your life, hopefully avoiding future contact with publicly shared jars of candy.

Scientists are discovering that plants also have a type of immune system that attacks bacteria and fungi. Instead of white blood cells, plants produce an abundance of things called flavonoids. And some very ingenious scientists here at Rensselaer are starting to ask the question, “If it works for plants, might it also work for humans?”

Why bother checking if flavonoids stop the spread of bacteria in humans? The answer is simple: society is running out of ways to kill bacteria. New methods to stop bacteria are becoming essential as the old methods – antibiotics like Z-pak, penicillin, amoxicillin, and the like – become less and less effective.

Despite being very simple organisms, bacteria have developed some exceptionally smart survival systems. As they and their brethren have been bombarded by decades by pills and sticky medicines, they have slowly adapted to survive the barrage. One of these adaptations actually allows bacteria to pump toxic compounds like antibiotics out of their systems before the drugs can leave lasting damage. And so, the antibiotics go in and the bacteria spit them right back out. To combat this, doctors need entirely new molecules to throw at the bacteria. When faced with a new molecule, the bacteria simply will not have the systems in place to combat it and they will be killed.

Of course there are a lot of different chemicals and compounds out there besides antibiotics that will kill bacteria on contact. But, drinking pool chlorine or injecting battery acid is not something I look forward to. I am guessing you are with me on at least this point. So, new drugs to combat bacteria also need to be safe for the very sensitive human system.

Flavonoids have long been praised for their health benefits (eat your kale), but little is understood about their antimicrobial effects. Mattheos Koffas who works in the Center for Biotechnology and Interdisciplinary Studies and a team of researchers at the State University of Buffalo and in the pharmaceutical industry are looking at how effective flavonoids might be in combating bacteria in the human system. The scientists recently published a paper in the journal PLoS One that shared some very promising results on the future uses of flavonoids in medicine.

What they found was that naturally occurring flavonoids in plants had strong antibacterial and antifungal properties. They were also safe to human cells. Koffas and the team then took the research an important step forward by designing non-natural flavonoids in the lab. These new molecules took all the best aspects of the natural flavonoids and essentially turned up the volume.

What they found was that these chemically-synthesized non-natural flavonoids were even more potent against bacteria and fungi. They also appeared safe for human use.

The research provides an important path forward for a new class of antimicrobial agents – flavonoids. Koffas plans to continue to study the potential of these new molecules.

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Wayne Bequette is a professor in the Department of Chemical and Biological Engineering. We ask Wayne about his work:

Q: Tell me a little bit about your work on creating an artificial pancreas to help people with juvenile diabetes.

A: Developing a fully closed-loop artificial pancreas requires a continuous glucose sensor, a continuous insulin infusion pump and a control algorithm to connect the sensor and pump. We have been tackling this problem one step at a time: first by developing a hypoglycemic alarm to warn of low blood glucose; next by constructing a simple pump shut-off algorithm to prevent hypoglycemia at night; then finally developing a fully closed-loop system. It is absolutely critical for engineers to have good medical collaborators to have a true impact, and I am fortunate to have excellent colleagues at Stanford University who perform the clinical studies.

You started your chemical engineering career working in the oil refinery industry. How did you end up in leading-edge biomedical engineering?

When I arrived at Rensselaer, I took the time to meet with just about every faculty member who was doing systems and control research. This led to me being asked to be on the dissertation committee of a graduate student in Biomedical Engineering, who was working on a drug infusion system to control a patient’s blood pressure and cardiac output. I introduced him to model predictive control (MPC), which was (and remains) the most commonly used advanced control technique in the oil refining industry. In no time he had coded up an algorithm and applied it to his drug infusion problem. About 10 years ago I decided to move into diabetes technology. One motivation was that a sister of mine has type 1 (also known as juvenile) diabetes; it turns out that many researchers in the area have a similar personal connection to the disease.

You seem to have a bit of a green streak, as your research also brushes up against fuel cells, biodiesel, and coal gasification. Is sustainability and efficiency important to you?

In addition to performing research in “green technologies,” I try to live a reasonably energy-efficient lifestyle. Most days (well, nine months out of the year), I bike to campus from my home in Albany. The 25-mile round trip by bike saves a 32-mile roundtrip by car, reducing fuel consumption and carbon dioxide production. The main challenge with my bike ride is that, in both directions, it ends with an uphill climb.

Tell me a little about the books you’ve authored. It has to take a ton of work to write a textbook. Was it challenging?

You certainly learn a lot by writing a textbook. My first textbook, focused on process dynamics and emphasized nonlinear behavior; I wrote it at a time in my career when I was learning about chaos and related topics. My second textbook, focused on control system design, was the first in chemical engineering to emphasize a model-based approach.

When did you know or decide that you wanted to be a engineer?

In seventh grade I told a friend that I liked math and science and he convinced me that I should be an engineer.

What would you say to young students and high schoolers who are thinking about studying engineering or becoming an engineer?

I would say that some of the math that you learn in high school may seem abstract at the time, but the more math that you learn, the better prepared you will be for an engineering career.

Outside of the lab and the classroom, what do you like to do for fun?

Three years ago, motivated by the 2008 Olympics, I began strength training and pole vaulting again. At the age of 54, I am actually a better vaulter than I was in high school, which probably says more about how bad I was in the early 1970′s than how good I am now. In addition to hiking and biking much of the year, I ski in the winter—although not aggressively enough to keep up with my two kids (ages 12 and 15).

To read more about Bequette and his research, see a Rensselaer story here, an Approach post here, and a great Channel 13 story here.

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As a loyal reader of The Approach and our steady stream of news stories, you’ve likely heard quite a bit about graphene. The material increasingly is at the forefront of nano and materials research. And for a good reason—this stuff has some seriously cool properties and potential applications.

Graphene is a single layer of carbon atoms. Linger on this fact for a moment: graphene is only one atom tall. For all intents and purposes, the only thing that flatter or less tall than graphene (unless you bring quarks, neutrinos, or other elementary particles to the party) is nothing at all.

It’s difficult to conceptualize this kind of uber-flatness, and nanoscale graphene is far too small for us to get a good look at. However, if you were able to shrink yourself down to the nanoscale and pay a visit to a sheet of graphene, it would look the like above image: endless carbon atoms arranged like a chicken-wire fence, stretching far beyond the horizons.

It’s not a coincidence that “graphene” sounds a lot like “graphite.” Graphite is bulk carbon and made up of countless layers of graphene all crammed together. The charcoal we use in our barbeques, and diamonds we use in dentists’ drills and wear as jewelry are also mostly carbon, but with their atoms arranged in a slightly different way.

Researchers theorized for many years about the existence of graphene, but it wasn’t until 2004 that researchers were able to isolate it. The tool they used for this major feat? Store-bought scotch tape. They gently dabbed the sticky side of the tape on bulk graphite. Their low-tech approach dd the trick. The adhesiveness of the tape was strong yet gentle enough to strip away layers of graphene from the graphite. Using a powerful electron microscope, the researchers were then able to find and identify individual layers of graphene on the tape. True story.

Graphene has all sorts of interesting properties. It’s arguable that the most intriguing use for graphene, however, is for nanoelectronics. The microprocessors and chips at the heart of modern electronics lean heavily on two materials: silicon and copper. Silicon is a stellar semiconductor, which means it can be made to be conducting or insulating–can be switched “on” or “off.” There are billions of these on/off switches, called transistors, on the chips in your cell phone, laptop, digital camera, TV, or basically any other electronic device. We use very thin layers of nanoscale copper called interconnects to carry electrons around the silicon chips.

As our phones and computers get smaller and smaller, they demand smaller chips. Similarly, there’s a chip industry mantra called Moore’s Law, which states the number of transistors on a computer chip—and thus the chip’s speed—should double every 18 to 24 months. Moore’s Law a tough customer. Looking ahead several years and several generations of chips, the industry has come to terms with the harsh reality that silicon and copper’s days are numbered. The smaller we shrink our silicon transistors and copper interconnects, the more we see how their effectiveness is impeded by weird quantum phenomena. The rules of physics take a turn for the strange and unexpected when stuff gets so tiny.

Researchers at Rensselaer are investigating ways to create graphene that would be a suitable replacement for both interconnects and transistors. Engineering prof Nikhil Koratkar is looking at graphene for transistors, while physics prof Sarok Nayak is studying graphene interconnects.

The blue ocean, pie-in-the-sky goal is to bring these ideas together and one day make chips from a single material. This idea, called monolithic integration, means the transistor and interconnects would be made of essentially the same stuff. It would likely shave off many dozens of steps from the chip manufacturing process, saving an abundance of time, money, and effort.

Is graphene be the material that finally makes all of this a possibility? Could be. Nikhil, Saroj, their students, and others are Rensselaer are working heard to make it so.

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Linda Schadler is an associate dean in the Rensselaer School of Engineering and a professor in the Department of Materials Science and Engineering. We ask Linda about her work:

Q: Of all the stuff in the world to study, why pick something as small as nanoparticles?

A: Nanoparticles may be small, but they have a huge amount of surface area. That means that they can have a large impact on the polymers we mix them with, and can sometimes change properties by orders of magnitude. I started my research career studying interfaces in traditional particle-filled polymer composites, so when I found something with a huge amount of interface, it seemed like a natural switch.

So, is there anything left after nanotechnology? Can we study things that are even smaller?

I sure hope nanotechnology is not the end of the road, but when you get below a few nanometers, you are starting to talk about molecules that have been studied for a long time. I think that the next big steps will be in better understanding how to predict the properties of heterogeneous materials and how to make bulk nanostructured materials on a commercial scale. There is a lot of work to do there. There is also a lot of room for creating biological/synthetic material structures with unique combinations of properties. I don’t think we will run out research topics anytime soon!

You had a hand in an experiment that was tested on the outside of the International Space Station. Tell me a little bit about it.

Space applications sometimes require moving parts that must have a very low coefficient of friction, but that also don’t wear down. Fluoropolymers are used in bikes, and on skis, and many other moving parts because of the low coefficient of friction. BUT, they have a large wear rate. We found that by adding 1 volume percent of nanoscale alumina nanoparticles to polytetrafluorethylene (PTFE – one example is Goretex), that we could create a very low coefficient of friction material with four orders of magnitude lower wear rate than the unfilled polymer. It was like adding a little fairy dust changed everything! There was enough interest that it was tested in space on the international space station on tribometers built by alumnus Greg Sawyer from the U. of Florida. The samples just came down out of space and we are waiting to do some post space testing on them. It was a very exciting study – it makes me smile every time I think about our samples spending time in space.

You and others created the Molecularium Project, which has resulted in two stellar movies. What’s next for Molecularium?

We are about to launch NanoSpace – an online educational Molecularium experience. Check it out at www.molecularium.com later this year. It will have games, movies, and information, and we hope that kids have a blast learning about molecules with it.

Before joining Rensselaer, you were a faculty member at Drexel in Philadelphia. Did you ever visit the Liberty Bell? How about Independence Hall?

My parents took me to the Liberty Bell and Independence Hall when I was small due to an interest I had in the colonial time period, and I have been back many times since. Most recently with my children. I also went to graduate school in Philadelphia and learned a lot from the exposure to the different cultures within Philadelphia, and the international students at the University of Pennsylvania. I loved teaching at Drexel University. They have a mandatory co-op program and the students come into the classroom with a practical understanding of what they will apply in the workplace. The students there are a huge pleasure and challenge to teach.

When you’re not in the lab or the classroom, what do you like to do?

I like to be in the mountains, hiking, skiing, kayaking, or reading a book. I feel most at peace when I am in the mountains and spend as much time there as I can. My husband and two kids and I just finished hiking the 46 mountains over 4000 feet in the Adirondacks (thus the picture) and joined the 46er club this spring. This summer we will climb Mt. St. Helens in Washington State, and hopefully make it to the White Mountains of NH.

I also like to do small triathlons with the Niskayuna Women’s Triathlon Club. A great way to get outdoors regularly and socialize at the same time.

To read more about Schadler and her research, click here, here, and see other Approach posts here.

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On June 6th, I traveled with three other RPI students (Michelle Decepida ’13, Adriana Rojas ’12, and PhD candidate Eduardo Castillo) to Madrid for an eight-week collaborative research project at the Institude for Microelectronics in Madrid, Spain. The research focused on the development of thermoelectric materials, or materials which generate electricity when there is a flow of heat through them—very similar to solar cells which generate electricity when light flows through them. These materials have the potential to provide vast amounts of energy and have expanded the diversity of clean energy technologies.

We had two primary research goals: 1) develop a procedure for producing high quality films of bismuth telluride on a silicon substrate via pulsed electrodeposition, and 2) design and install the experimental set-up required to measure the figure of merit of the films.  The thermoelectric effect that drives the power generation capability of these materials is improved remarkably when the material is dimensionally very small— like a thin film from 100-5,000 nanometers. Thin film technology is generally very expensive; however, the same process used to plate car wheels with chrome metal (electrodeposition) can be used to deposit thermoelectric materials too! Electrodeposition is a well known technology and much cheaper to do than other thin film methods. Therefore, our research is focused on optimizing the electrodeposition procedure to produce high quality thermoelectric films.

The figure of merit for thermoelectric devices is a standard measure how well they perform. Current commercial products have a figure of merit just below 1. In order for this technology to be viable for mass production, the figure of merit needs to be around 3. Measuring the figure of merit is fairly easy for large materials, but for thin films it is quite difficult, hence it is an active area of research among scientists.

In addition to conducting research we traveled around Spain and visited many of the most famous areas here. The museums in Madrid have many famous paintings from Spanish artists such as Picasso and Salvador Dali (so incredible to see in person)!

Additionally, the San Fermin festival was from July 7-14 in Pamplona—it’s the festival where the famous “running of the bulls” occurs every year. Michelle, a junior engineering student at RPI, and I traveled to the festival for a weekend and joined the people of the town in the celebrating the event. Earnest Hemmingway was right about what he said of the Matadors, they are very brave! Eduardo and Adriana (senior engineering student) traveled with us to a hostel, the first time for all of us, and met a lot of really cool people from all over the world (Sweden, Australia, Denmark, England)—and they all spoke English too.

We learned a lot about the Spanish culture during our stay. Thirty minute coffee breaks are a common thing. Everyone looks forward to them so it’s rude not to invite everyone else in the lab when you go for a coffee. The students here are all graduate students or postdocs. They were very welcoming and made our stay here so enjoyable. We became fast friends and found ourselves wishing we could stay longer.

To read more about the faculty adviser of these students, Diana Borca-Tasciuc, click here and see her 3° interview on The Approach here.

For further reading about international experiences and study abroad at Rensselaer, check out my story here from a recent issue of the Institute’s Alumni Magazine.

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