When in Doubt, Lasers

When you want to see how anything works, whether it be a car, plant, or liver, you look inside. Everything fun and important is more than skin deep. The very first way of doing this was with dissections; getting your hands all dirty and such. In more recent years, we have progressed past this less precise method with technology like CT scans (that utilize x-rays) or MRI (which uses radio waves as well as a magnetic field). However, both of these methods have some serious drawbacks to them that restricts their use in certain fields. For instance, CT scans create images based on the density of materials, so if a specimen has a bunch of structures of similar densities, they can become very difficult to tell apart. MRIs on the other hand, are huge, clunky, complex, and crazy expensive (the bottom shelf MRI scanner costs more than $150,000, and they very quickly go up in price).

Clearly, the only way to solve this is with lasers. I mean, it worked with sharks.

Much Better.
Image Courtesy of ThinkGeek.com

Benjamin Hall, an undergrad who was working part time at the ARL (Applied Research Lab) here at Penn State, has been working with a technique called Laser Ablation Tomography (even the name sounds cool) to image things. The technique is pretty simple: you put an object like a root (they love doing roots and other plants stuff) on a moveable platform, fire up your lasers, and vaporize your sample layer by layer. At each layer, you can take what is essentially a photograph, allowing you to stitch together a 3D model of the sample at the end, complete with the internal structures. It's sort of like those 'cross section of a brain' exhibits you see at some museums, only with much much thinner slices. What results is a model like the one you see below. Using these models you can explore the sample as much as you want with extreme precision (~1µm).

Video Courtesy of L4iS LLC

Plant structures are clearly not the only thing you can model with this technique; it could also be used for things like material analysis. On denim jeans for example! On a side note, on the gif of the denim below, if you look closely you can see little mini 'fires', which would make sense as denim is flammable and the lasers are pretty much burning the denim away layer by layer – its just cool to see that that was captured on the model.

Video Courtesy of L4iS LLC

Since Mr. Hall started developing the process he has started his own company, Lasers for Innovative Solutions, based here in State College. The company focuses on services for agricultural businesses, as the technology allows you to quickly phenotype specimens (see what physical traits they have) that would be difficult to do in another manner. For example you could see just how one of your new types of sorghum is developing differently compared to other varieties.

Image Courtesy of L4iS LLC

Today's world is all about speed. We have seen this most recently with rapid prototyping using 3D printing, and this Laser Ablation Tomography is another way that research and development can occur at faster speeds. Now data can be acquired on materials or specimens without having to stain or otherwise prepare them (remember how annoying it was trying to prepare slides in biology in high school?). It certainly will not replace other imaging technologies, but there are certain applications where this newer technology is superior both time and quality wise. 

Penn State applied for and got a patent on the process (with Benjamin Hall as co-inventor), and the technology is being used both in Hall's private company as well as in research labs at PSU, most notably in the department of plant science.

Graphene: The Wonder Material

Most of you are probably familiar with graphene, that fancy new sheet of material that is one carbon atom thick, 207 times stronger than steel (by weight) and can conduct electricity. Many researchers tout graphene as the 21st century's "wonder material," able to be crafted into the next generation of electronics (beginning the 'post-silicon' era of processing), composite materials (materials made of multiple components with differing properties), as well as countless other applications.

Image Courtesy of Wikimedia

However, there are a few snags to tackle along the way before it gets into the practical realm. In order to tackle some of these problems and to gain a better understanding of the weird properties that come with essentially two-dimensional materials, the Center for Two Dimensional and Layered Materials (2DLM) was established in 2013, bringing together faculty and students from PSU as well as other institutions. The center is working on many exciting projects, but instead of making a separate post for each one, I'll briefly go over a couple of them in this singular post.

One of the major challenges to the use of graphene in industrial applications is the fact that it's just so hard to make a large, pure enough sample of the stuff. One method that has been brought up is called 'intercalation,' which basically means to get a sample of graphite and shove in a bunch of non-carbon atoms in order to more easily pull the sheets of carbon apart. On the molecular scale it would look like the image below. Previous attempts at this method had to use very strong agents that ended up ruining the material, but a group in the 2DLM was able to devise a way to process the reaction without them, meaning that now the reaction just needs to be sped up in order to get the process good for larger scale production.

Image Courtesy of Mallouk Lab/Penn State

Looking to an entirely different focus, the center also has a team that is working on a cool application of graphene: stretchy yarn! By weaving together a bunch of graphene strings, a fiber was created that is much superior strength-wise than other carbon fibers that have been experimented with.

Image Courtesy of Terrones Group/Penn State

Now this might not seem like much, but this carbon string has an abundance of applications. For instance the string may be used as a replacement for copper transmission lines, as graphene conducts electricity better than copper and is also much lighter. It's just better all around pretty much. One could also make trip wires out of it, if that's your thing.

The Center for Two Dimensional and Layered Materials is doing some pretty exciting stuff here at Penn State, and while I only was able to gross over two of the things they are working on right now, there is much much more (their publication list is pretty darn impressive). Graphene is an incredibly exciting material that will certainly change the way many of the things we use now are made. Get ready for the future guys, it's coming pretty fast.

Wasted Heat to Usable Electricity

When one energy form is turned into another, like when we convert electricity into light, the process is very rarely truly efficient. Instead, there is always some waste in the form of heat energy. For example, power plants are only around 33% efficient: only one third of the chemical energy in the coal or oil burned is turned into useable electricity.

Take an incandescent light bulb. If you've ever touched one after being on for any period of time at all, you're bound to get burnt. Just look at the IR image of an incandescent light bulb below: at the top, this particular bulb was reaching temperatures upward of 300 degrees fahrenheit!

Image Courtesy of Zaereth

Bruce E. Logan, professor of environmental engineering has devised a solution to harness low-grade heat (heat that is low to mid temperature that is not very energy dense, like exhaust from a car or power plant heat waste) and turn it into electricity. His solution involves an ammonia battery that can be regenerated using the waste heat we talked about earlier. 

Without heat, the battery could go through one cycle, similar to the way that your average AAA single-use battery operates. Typical rechargeable batteries can be regenerated by running electricity the opposite way it usually goes, forcing the reaction that is occurring in the battery to go in reverse. 

What is unique about the ammonia based battery however is that it can be regenerated back to full capacity using waste heat instead of electricity, allowing the cycle to continue once more without electrical input.

Image of the Ammonia based battery
Image Courtesy of Wulin Yang/Penn State

Right now the system isn't incredibly optimized (as you can probably tell from the photo above); right now about 29% of the chemical energy that gets stored into the battery is converted to electricity. This can be compared to around an 85% efficiency for lead-acid batteries (the type that you'd find in your car). However this efficiency will be able to be brought up significantly as they sure up all parts of the battery.

This battery could have some exciting impacts on the efficiency of energy production. Look at nuclear power plants for instance. These plants need very high temperatures in order to produce electricity, and after the heat is utilized, it is moved to those humungous cooling towers that you associate with nuclear power plants. Those aren't the things that are producing the electricity - it's for cooling the fluid! By adding these ammonia batteries to systems like these, the amount of heat that is wasted and put to the atmosphere can be reduced significantly while simultaneously increasing the amount of electricity that is produced. Seems like a win-win to me!

Image courtesy of Own Cliffe

Unfortunately I was not able to go in detail on the workings of the battery and the cool complexation reactions that allow this thing to work, but if you're interested in learning more about what exactly is happening here, a paper on the subject (that explains the process surprisingly well) can be found here.

For a Trip to the Restricted Section

The curses and charms and hexes were cool it's true, but what really caught my attention in Harry Potter was the invisibility cloak, for the simple reason that it seemed like it could conceivably exist. And now it does. Get ready to take trips to your local library in the middle of the night and have the best floating head costume ever!

Image courtesy of Warner Bros. via IMDB

Okay I may have exaggerated that a bit. Okay maybe more than a bit... But major progress is being made, and it is very exciting. Xingjie Ni, a new assistant professor of electrical engineering here at Penn State, is heading up the team of researchers working on a new cloaking device. While other attempts at this technology have utilized thing like giant tanks of water or lasers, Ni's method utilizes a thin fabric that is 1000 times thinner than a human hair to get the job done. To explain how this skin works we must first take a brief look at the way light reacts when it hits an object.

Image courtesy of J. Gabrielse

All objects on some level are bumpy. So when light comes in and hits an object, it get scattered all around at many many different angles. This can be seen in the photo above. Our brain can process all of these different waves in order to come up with the 3 dimensional shape and depth of the object. 

However, if you are able to change the way that light is bouncing off of the object, you can change the way that we see it. That is exactly what Ni is doing. By creating a surface that is covered in these little gold 'bricks' that change how the light bounces off of the object it is covering, the object is rendered undetectable and appears completely flat. Essentially by reflecting the light in a way that it would be reflected if the object were flat, the object appears flat to the human eye. An image of this process can be seen below. If the material was not covered in the little gold 'antennae,' the light would be going every which way. Instead, it has a clean outbound path.

Image courtesy of Xiang Zhang Group

Now, this technology has some serious caveats that must be accepted when looking at this technology. First, the surface must be custom made for the object that it is hiding, as the little gold blocks must be perfectly configured and aligned. Second, right now the skin-like material can only hide an object that is a few micrometers in size. But the team is looking into changing the way they are making the material in order to accommodate larger objects. 

This method of invisibility is my no means perfect, but as a first toe in the water for this particular technology, it is very promising. In the future all of the limitations can be worked out until we perfect a way to sneak into the adult fiction section of the library.

A paper published in Nature about a month ago on the topic can be found here.

All Cancer Cells Off at Exit 12!

Metastasis is one of the scariest terms one can hear in regards to cancer. It means that the cancer cells have detached from the original tumor and have started to spread through the lymph and/or blood vessels of the body to later reattach in a new location to start a new tumor. Once cancer metastasizes, it become much harder to treat.

Metastasis
Image Credit: National Cancer Institute

A new device from Tony Jun Huang's lab may help us better understand Metastasis and provide a more effective way to study the phenomenon, as well as allow doctors to better screen cancer patients  to see how they are reacting to treatment.

The device is about the size of two pennies, and allows a quicker and more efficient way to sort cancer cells from blood samples. 

The image over is a mock-up of what happens inside the device. From the top, an unsorted sample flows down to the bottom. As it goes, acoustic waves from either side push white blood cells to one side, while pushing the circulating tumor cells to the other side. This method has proven to have a successful separation rate of more than 83%. 

This method has significant improvements over existing cell separation methods. One method employs tumor-specific antibodies that bind with the cancer cells to flag them, but to use this method the right kind of antibodies must be known ahead of time, which significantly limits the effectiveness of the method. A second method is pretty much a centrifuge with can separate the cells based on size, but these devices can cost anywhere from $200,000 to $1,000,000 and reduce cell viability by up to 99%. In a lot of research, the cells need to be alive in order for anything useful to be gathered from them. 

The new device that relies on acoustics has the potential to solve all of these issues. A continuous sample can be flowed through the device, aiding in speed. The device is about the size of two pennies, a far cry smaller than a huge centrifuge type device. The small and simple size of the device also means that it is rather cheap, and could be disposable, a trait that is very important when dealing with medical tests (no one wants their blood getting mixed up with someone else's in a device that might tell them how well their treatment is going). Further, because the acoustic waves are around the same energy level as the waves used in ultrasonic imagery, they do not damage the cells, and can be used in a clinical setting.

The acoustic separation device
Image Credit: Tony Jun Huang, Penn State

"Looking for circulating tumor cells in a blood sample is like looking for a needle in a haystack," said Professor Huang, and this new cell sorter is like getting a giant electromagnet to place over the haystack in that it makes it so much easier and so much faster. The technology is going to help future research into cancer, as well as be there for doctors to use for diagnosis, prognosis, and treatment check-ups. Cancer is becoming ever-more treatable, and this device is one good step towards making it so.

If you'd like to learn more about the use of standing acoustic waves to sort microparticles, you can read this article published in the journal Lab on a Chip.

Cleaning Up Oil with Plastic

The 2010 Gulf of Mexico oil spill was the worst in US History and had huge, immediate impacts on the coastal ecosystems of the area. 3.19 million barrels of oil were spilled into the Gulf, an amount that could clearly be seen from space, like this photo taken from the ISS on May 5th, 2004 demonstrates. Cleaning up this disaster is obviously of utmost concern, but current clean up methods are inefficient in so many ways.

Deepwater Horizon Oil Spill as seen from the ISS
Image Credit: NASA

Physical barriers (floating booms) were used to try to surround the oil slick, but this method is only is successful when the water is calm and slow moving. 

Booms used in an attempt to protect barrier island during Deepwater Horizon
Image Credit: Kris Krug

Another method used was the use of dispersant, which helps the oil mix with the water instead of forming giant slicks. This is good in the short term, but just because you can't see the oil, it doesn't mean it's not there. The idea is that the smaller oil droplets will evaporate, and bacteria will slowly degrade the smaller oil droplets. However, the effectiveness of this is questionable. Dispersants can potentially enter the food chain and harm wildlife. Further, the dispersant-oil mixture with the water can be more harmful than just the oil itself!

This is where Penn State Professor Mike Chung comes into play. Chung began looking at hydrogels, the polymers in diapers that absorbs children's unfavorables. The issue with this is that it absorbs water as well as oil, and it disintigrates after it absorbs water… not super useful. Luckily we've got some pretty smart cookies here at Penn State, so Chung's lab was able to create a new material that meets all of the criteria.

It's called PetroGel™(it's trademarked and everything!), and it's wonderful. Structurally, it's a low density polyolefin (polymers produced from alkenes), which pretty much means it's a type of plastic. Functionally, the polymer can absorb 10 times its volume in crude oil in 10 minutes. In 24 hours, it can absorb 40 times its volume, and it doesn't absorb water. Even better, the material stays as a solid after absorbing the oil, making clean up a breeze. 

PetroGel absorbing diesel gas
Image Credit: Penn State

As plastic is an oil product, the gel along with the oil that it absorbs can be refined just like regular crude oil. That's 3.19 million barrels of crude oil that could have been saved and used in the Deepwater Horizon oil spill. At $46.26 per barrel at the time of writing this, that's a little under 150 million dollars. 

To top it all off, polyolefin polymers are rather inexpensive, and it is predicted that in large scale production the product could cost less than $2 per pound. PetroGel™is an economical as well as an environmental win.

PetroGel™will undergo more rigorous testing with the US Dept. of the Interior's Bureau of Safety and Environmental Enforcement starting this winter, so maybe we'll see Penn State's developments used in the next inevitable oil spill.

They Move! - Intracellular Motors

When one thinks of a motor, they often think of a car motor or perhaps an electric motor. Something big hulking machine that makes your car run or spins the beater of your KitchenAid™.  Something similar to this:

Boiling it down however, a motor is something that coverts some form of energy into mechanical energy, that is, movement. Simply, a motor is something that spins. When you remove the notion of a motor being a large electrically driven hunk of metal, all sorts of possibilities arise. Possibilities like tiny nano-sized motors that can go inside cells. Tiny motors, inside your body, inside your cells. And they look pretty cute (the video has no sound).

In collaboration with ESPCI Paris (a physics and chemistry engineering college), Tom Mallouk's research group has created tiny rods made of gold and ruthenium that can be manipulated both collaboratively (many rods together) and independently using ultrasonic waves (sound higher pitched than humans can hear) as propulsion and magnetic waves as steering. Even better, the power-density of the ultrasonics used with the rods is in line with that of medical imaging solutions we use today, so we know its safe. Previous versions of this budding technology were incompatible with biological systems as it used fuels that were hazardous to living cells. These new rods both work well within the cytoplasm of the cell and are nontoxic.

Light Microscope and Scanning Electron Microscope Images of the Nanometers 

Just seeing what these little rods can do gives you an idea of the wide range of applications for these new little critters. Take this video of a bunch of these rods working cooperatively to rotate a line of cells.

In one situation you could make the little rods go insane, blending the internals of the cell. If you were able to target cancer cells with these rods, you could absolutely obliterate the cells, killing the cancer.

On the complete other end of the spectrum, delicate control of the rods could help future scientists learn more about the internal workings of the cytoskeleton of the cell (the network of filaments and tubules that provide support and movement throughout the cell) by poking and prodding around in ways we never have been able to before. Delicate control could also diagnose and provide therapy for various diseases in a noninvasive fashion.

These little rods are not only 50 times thinner than a human hair; they're also 50 times more useful. The technology is still in the very preliminary stages, but progress is being made. Brain surgery in the future may consist of injecting these little rods into your body, having the rods be controlled to go up in your brain, fix whatever needs to be fixed, and then get peed out. That seems a lot better than getting your head cracked open. As long as they don't accidentally crank up the speed and blend your brain...  well that'd be awkward.

If you'd like to learn more about this subject, a PDF of one of his recent publications on the topic can be found here.

Evolved to Succeed

“One general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die.” - Charles Darwin, The Origin of Species

Natural selection and evolution leads to traits that promote the overall success of a species. Some adaptations that nature has developed over millions of years are so clever and advanced that it becomes more advantageous to rip-off ideas that nature came up with, rather than try to develop our own. This biological plagiarism is called biomimicry, and is becoming an ever more popular form of research. 

This biomimicry is a aspect of research that Dr. Tak-Sing Wong, assistant professor of mechanical and nuclear engineering, is focusing on. Named one of the 35 Innovators Under 35 by the MIT Technology Review, Tak-Sing Wong is researching biologically inspired surfaces here at Penn State.














One of his research projects takes cues from the wondrous pitcher plant. Pitcher plants grow in soil which lacks nutrients important for the plant's growth, and since they are still here today, you know they have developed a mechanism to get them around this barrier to survival. Pitcher plants have modified leaves that resemble pitchers that one could serve iced tea in. At the bottom of these pitchers is a pool of bacteria or enzymes which dissolves the unsuspecting insect prey, allowing the plant to absorb the critical nutrients that the soil lacks. One of the big issues that the pitcher plant had to overcome to become successful is how to keep the insect inside the plant after it falls in the pitcher.

Through copious generations of survival (and death of unsuccessful plants), the pitcher plant has developed an incredibly slippery surface, a surface that insects cannot grip onto, keeping them trapped inside the pitcher for digestion. Wong's laboratory has taken cues from the pitcher plant and has created an incredibly slippery surface by assembling a porous solid impregnated with a lubricant, creating a "stable, defect-free, inert "slippery" interface."



The surface, named SLIPS (Slippery Liquid-Infused Porous Surfaces) can repel pretty much any liquid or organism, allowing it to roll right off, as seen from this video taken from his lab. Many more examples of the surface's prowess can be found at the bottom of Wong's website.



Due to its ability to function in rather harsh conditions (high pressures, resisting icing, physical stressors), the surface has many applications, like in medical equipment to prevent the harboring of bacteria, on boats to prevent barnacle growth, or in liquid transport systems that undergo physical stress. Maybe coat your clothes with it to make that ketchup slide right off!

Tak-Sing Wong's lab is doing some fantastic stuff, so this might not be the last time you hear about him here. If you'd like to read a little bit more in depth on this particular project, the article that was published in Nature can be found here.

More than Calamari

The future is always envisioned as a world of wondrous gadgets and incredible foreign technologies. The path traveled to reach this point however, becomes a little bit fuzzier. People see the final destination, but do not often consider the painstaking process of research that goes into every facet of new technology. Here at Penn State, around 805 million dollars is put into research per year. Simply, Penn State is a very active research university. In this blog, I want to share some of the most interesting and promising research that is being done here at University Park. I want to share what makes Penn State so exciting while at the same time giving insight for those people interested in pursuing undergraduate research.

One of the most exciting fields of research right now (at least in my opinion) is materials science. Most of the material science labs are in the Millennium Science Complex, so you know it has to be cool. 

They don't put just any old research into a building like that.

Material science is all about developing new materials to improve the products that improve our lives. Take medical implants for example. Right now implants can deteriorate. Our bodies do not recognize them as friendly, which means not only do our bodies not put in the effort to upkeep them, they actively reject the foreign objects. This is where Melik Demirel's lab (and squid!) comes in.

Squid teeth have a very unique property in that they are self-healing in the presence of water (which isn't that hard to come by for a squid). Thanks to the wonder of genetic engineering, they are able to take the protein which enables this to occur, stick it in a bacteria, have the bacteria divide like bunnies, and then harvest as much of this protein that they want. Its like a little farm for protein. They then can take the protein and combine it in a two-part polymer that can be formed into whatever shape suits your fancy. But now when your application tears, just add water! This video from their lab demonstrates the polymer's abilities quite well.

Since our bodies are more than 50% water, medical implants could utilize this polymer to great effect. The lifespan of implants could be dramatically increased, reducing the number of invasive procedures an implant patient would have to go through. But this is just one application of this new polymer. There are endless possibilities for materials that self-heal with water. Demeril proposes its use in hard-to-reach cabling: "If one of the fiber-optic cables under the ocean breaks, the only way to fix it is to replace it. With this material, it would be possible to heal the cable and go on with operation, saving time and money."

So in the future, when you get a self healing medical implant that saves your life, thank the squid. And thank Penn State.