Nanotechnology – Curious Cat Science and Engineering Blog

Bacteriophages Enter Bacteria Using an Iron Tipped Spike

curiouscat — Fri, 02 Mar 2012 13:36:14 +0000

Bacteria-Killing Viruses Wield an Iron Spike

Forget needles in haystacks. Try finding the tip of a needle in a virus. Scientists have long known that a group of viruses called bacteriophages have a knack for infiltrating bacteria and that some begin their attack with a protein spike. But the tip of this spike is so small that no one knew what it was made of or exactly how it worked. Now a team of researchers has found a single iron atom at the head of the spike, a discovery that suggests phages enter bacteria in a different way than surmised.

Wherever there are bacteria you will find bacteriophages; digestive tracts, contaminated water, and feces are usually a good start. These viruses begin their dirty work by drilling into the outer membrane of bacteria. Once completely through all of a bug’s defenses, the phages inject their DNA, which essentially turns the bacterium into phage-producing factories. Eventually, the microbes become filled with so many viruses that they burst, releasing a new horde of phages into the environment.

Bacteriophages are amazing. It is so interesting to learn about amazingly creative solutions that have evolved over time. Real-life science is not easy to match with fiction that springs from our imaginations.

NASA Biocapsules Deliver Medical Interventions Based Upon What They Detect in the Body

curiouscat — Fri, 10 Feb 2012 10:31:54 +0000

Very cool innovation from NASA. The biocapsule monitors the environment (the body it is in) and responds with medical help. Basically it is acting very much like your body, which does exactly that: monitors and then responds based on what is found.

The Miraculous NASA Breakthrough That Could Save Millions of Lives

The Biocapsules aren’t one-shot deals. Each capsule could be capable of delivering many metred doses over a period of years. There is no “shelf-life” to the Biocapsules. They are extremely resilient, and there is currently no known enzyme that can break down their nanostructures. And because the nanostructures are inert, they are extremely well-tolerated by the body. The capsules’ porous natures allow medication to pass through their walls, but the nanostructures are strong enough to keep the cells in one place. Once all of the cells are expended, the Biocapsule stays in the body, stable and unnoticed, until it is eventually removed by a doctor back on Earth.
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Dr. Loftus [NASA] thinks we could realistically see wildspread usage on Earth within 10 to 15 years.
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The cells don’t get released from the capsule. The cells inside the capsule secrete therapeutic molecules (proteins, peptides), and these agents exit the capsule by diffusion across the capsule wall.

NASA plans to use the biocapsules in space, but they also have very promising uses on earth. They can monitor a diabetes patient and if insulin is needed, deliver it. No need for the person to remember, or give themselves a shot of insulin. The biocapsule act just like out bodies do, responding to needs without us consciously having to think about it. They can also be used to provide high dose chemotherapy directly to the tumor site (thus decreasing the side effects and increasing the dosage delivered to the target location. Biocapsules could also respond to severe allergic reaction and deliver epinephrine (which many people know have to carry with them to try and survive an attack).

It would be great if this were to have widespread use 15 years from now. Sadly, these innovations tend to take far longer to get into productive use than we would hope. But not always, so here is hoping this innovation from NASA gets into ourselves soon.

MIT Engineers Design New Type of Nanoparticle for Vacines

curiouscat — Tue, 22 Feb 2011 23:44:12 +0000

MIT engineers have designed a new type of nanoparticle that could safely and effectively deliver vaccines for diseases such as HIV and malaria. The new particles, described in the Feb. 20 issue of Nature Materials, consist of concentric fatty spheres that can carry synthetic versions of proteins normally produced by viruses. These synthetic particles elicit a strong immune response – comparable to that produced by live virus vaccines – but should be much safer, says Darrell Irvine, author of the paper and an associate professor of materials science and engineering and biological engineering.

Such particles could help scientists develop vaccines against cancer as well as infectious diseases. In collaboration with scientists at the Walter Reed Army Institute of Research, Irvine and his students are now testing the nanoparticles’ ability to deliver an experimental malaria vaccine in mice.

Vaccines protect the body by exposing it to an infectious agent that primes the immune system to respond quickly when it encounters the pathogen again. In many cases, such as with the polio and smallpox vaccines, a dead or disabled form of the virus is used. Other vaccines, such as the diphtheria vaccine, consist of a synthetic version of a protein or other molecule normally made by the pathogen.

When designing a vaccine, scientists try to provoke at least one of the human body’s two major players in the immune response: T cells, which attack body cells that have been infected with a pathogen; or B cells, which secrete antibodies that target viruses or bacteria present in the blood and other body fluids.

For diseases in which the pathogen tends to stay inside cells, such as HIV, a strong response from a type of T cell known as “killer” T cell is required. The best way to provoke these cells into action is to use a killed or disabled virus, but that cannot be done with HIV because it’s difficult to render the virus harmless.

To get around the danger of using live viruses, scientists are working on synthetic vaccines for HIV and other viral infections such as hepatitis B. However, these vaccines, while safer, do not elicit a very strong T cell response. Recently, scientists have tried encasing the vaccines in fatty droplets called liposomes, which could help promote T cell responses by packaging the protein in a virus-like particle. However, these liposomes have poor stability in blood and body fluids.

Irvine, who is a member of MIT’s David H. Koch Institute for Integrative Cancer Research, decided to build on the liposome approach by packaging many of the droplets together in concentric spheres. Once the liposomes are fused together, adjacent liposome walls are chemically “stapled” to each other, making the structure more stable and less likely to break down too quickly following injection. However, once the nanoparticles are absorbed by a cell, they degrade quickly, releasing the vaccine and provoking a T cell response.

read the full press release

Atomic Force Microscopy Image of a Molecule

curiouscat — Fri, 28 Aug 2009 12:30:10 +0000

The delicate inner structure of a pentacene molecule imaged with an atomic force microscope. For the first time, scientists achieved a resolution that revealed the chemical structure of a molecule. The hexagonal shapes of the five carbon rings in the pentacene molecule are clearly resolved. Even the positions of the hydrogen atoms around the carbon rings can be deduced from the image. (Pixels correspond to actual data points). Image courtesy of IBM Research – Zurich

IBM scientists have been able to image the “anatomy” — or chemical structure — inside a molecule with unprecedented resolution. “Though not an exact comparison, if you think about how a doctor uses an x-ray to image bones and organs inside the human body, we are using the atomic force microscope to image the atomic structures that are the backbones of individual molecules,” said IBM Researcher Gerhard Meyer. “Scanning probe techniques offer amazing potential for prototyping complex functional structures and for tailoring and studying their electronic and chemical properties on the atomic scale.”

The AFM uses a sharp metal tip to measure the tiny forces between the tip and the sample, such as a molecule, to create an image. In the present experiments, the molecule investigated was pentacene. Pentacene is an oblong organic molecule consisting of 22 carbon atoms and 14 hydrogen atoms measuring 1.4 nanometers in length. The spacing between neighboring carbon atoms is only 0.14 nanometers—roughly 1 million times smaller then the diameter of a grain of sand. In the experimental image, the hexagonal shapes of the five carbon rings as well as the carbon atoms in the molecule are clearly resolved. Even the positions of the hydrogen atoms of the molecule can be deduced from the image.

Read full press release: IBM Scientists First to Image the “Anatomy” of a Molecule

Nanoparticles With Scorpion Venom Slow Cancer Spread

curiouscat — Wed, 22 Apr 2009 14:36:39 +0000

In a, chlorotoxin molecules, colored blue and green, attach themselves to a central nanoparticle. In b, each nanoprobe offers many chlorotoxin molecules that can simultaneously latch on to many MMP-2s, depicted here in yellow, which are thought to help tumor cells travel through the body. In c, over time nanoprobes draw more and more of the MMP-2 surface proteins into the cell, slowing the tumor’s spread. Image from the University of Washington.

University of Washington researchers found they could cut the spread of cancerous cells by 98 percent, compared to 45 percent for the scorpion venom alone, by combining nanoparticles with a scorpion venom compound already being investigated for treating brain cancer.

For more than a decade scientists have looked at using chlorotoxin, a small peptide isolated from scorpion venom, to target and treat cancer cells. Chlorotoxin binds to a surface protein overexpressed by many types of tumors, including brain cancer. Previous research by Miqin Zhang‘s group combined chlorotoxin with nanometer-scale particles of iron oxide, which fluoresce at that size, for both magnetic resonance and optical imaging.

Chlorotoxin also disrupts the spread of invasive tumors — specifically, it slows cell invasion, the ability of the cancerous cell to penetrate the protective matrix surrounding the cell and travel to a different area of the body to start a new cancer. The MMP-2 on the cell’s surface, which is the binding site for chlorotoxin, is hyperactive in highly invasive tumors such as brain cancer. Researchers believe MMP-2 helps the cancerous cell break through the protective matrix to invade new regions of the body. But when chlorotoxin binds to MMP-2, both get drawn into the cancerous cell.

Research showed that the cells containing nanoparticles plus chlorotoxin were unable to elongate, whereas cells containing only nanoparticles or only chlorotoxin could stretch out. This suggests that the nanoparticle-plus-chlorotoxin disabled the machinery on the cell’s surface that allows cells to change shape, yet another step required for a tumor cell to slip through the body.

So far most cancer research has combined nanoparticles either with chemotherapy that kills cancer cells, or therapy seeking to disrupt the genetic activity of a cancerous cell. This is the first time that nanoparticles have been combined with a therapy that physically stops cancer’s spread.

Full press release

Harnessing Light to Drive Nanomachines

curiouscat — Thu, 04 Dec 2008 23:45:29 +0000

A team led by researchers has shown that the force of light indeed can be harnessed to drive machines – when the process is scaled to nano-proportions. Their work opens the door to a new class of semiconductor devices that are operated by the force of light. They envision a future where this process powers quantum information processing and sensing devices, as well as telecommunications that run at ultra-high speed and consume little power.

The energy of light has been harnessed and used in many ways. The “force” of light is different — it is a push or a pull action that causes something to move. “While the force of light is far too weak for us to feel in everyday life, we have found that it can be harnessed and used at the nanoscale,” said team leader Hong Tang, assistant professor at Yale. “Our work demonstrates the advantage of using nano-objects as ‘targets’ for the force of light – using devices that are a billion-billion times smaller than a space sail, and that match the size of today’s typical transistors.”

Full Press release

Carbon Nanotechnology in an 17th Century Damascus Sword

curiouscat — Wed, 01 Oct 2008 12:32:03 +0000

Carbon nanotechnology in an 17th century Damascus sword

Wootz, with its especially high carbon content of about 1.5%, should have been useless for sword-making. Nonetheless, the resulting sabres showed a seemingly impossible combination of hardness and malleability.
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Amazingly, they found that the steel contained carbon nanotubes, each one just slightly larger than half a nanometre. Ten million could fit side by side on the head of a thumbtack.
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It isn’t clear how ancient blacksmiths produced these nanotubes, but the researchers believe that the key to this process lay with small traces of metals in the wootz including vanadium, chromium, manganese, cobalt and nickel. Alternating hot and cold phases during manufacture caused these impurities to segregate out into planes. From there, they would have acted as catalysts for the formation of the carbon nanotubes, which in turn would have promoted the formation of the cementite nanowires.
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By gradually refining their blade-making skills, these blacksmiths of centuries past were using nanotechnology at least 400 years before it became the scientific buzzword of the twenty-first century.

2008 Lemelson-MIT Prize for Invention

curiouscat — Fri, 27 Jun 2008 14:55:30 +0000

The Lemelson-MIT Prize awards $500,000 to mid-career inventors dedicated to improving our world through technological invention and innovation. Joseph M. DeSimone received the 2008 award.

His exposure to polymer science led him to pursue a Ph.D. in chemistry from Virginia Polytechnic Institute and State University in Blacksburg, Va. At the age of 25, DeSimone joined the University of North Carolina at Chapel Hill (UNC) as an assistant professor in chemistry and launched the university’s polymer program with his mentor Dr. Edward Samulski. He resides there today as the Chancellor’s Eminent Professor of Chemistry at UNC, in addition to serving as the William R. Kenan, Jr. Distinguished Professor of Chemical Engineering at North Carolina State University.

Among DeSimone’s notable inventions is an environmentally friendly manufacturing process that relies on supercritical carbon dioxide instead of water and bio-persistent surfactants (detergents) for the creation of fluoropolymers or high-performance plastics, such as TeflonÂ®. More recently, he worked on a team to design a polymer-based, fully bioabsorbable, drug-eluting stent, which helps keep a blocked blood vessel open after a balloon-angioplasty and is absorbed by the body within 18 months.

DeSimone’s newest invention is PRINTÂ® (Particle Replication in Non-wetting Templates) technology, used to manufacture nanocarriers in medicine. At present, DeSimone’s Lab is vested in a variety of projects that also extend beyond medicine, including potential applications for more efficient solar cells and morphable robots. In 2004, DeSimone co-founded Liquidia Technologies with a team of researchers from UNC to make the technology available in the market. Liquidia is using the PRINT technology to develop precisely engineered nanocarriers for highly targeted delivery of biological and small molecule therapeutics to treat cancer and other diseases. DeSimone’s proposed applications for cancer treatment with the PRINT platform was instrumental in UNC landing a grant of $24 million from the National Cancer Institute to establish the Carolina Center for Cancer Nanotechnology Excellence.

“You can do all the innovating you want in the laboratory, but if you can’t get it out of the university walls you do no one any good,” said DeSimone. He instills an entrepreneurial spirit in his students that focuses on the importance of commercializing technology and scientific inventions. One of DeSimone’s greatest accomplishments is his mentorship of more than 45 postdoctoral research associates, 52 Ph.D. candidates, six M.S. theses and 21 undergraduate researchers. Furthermore, he speaks to groups of high school students about the inventive process and encourages them to learn and explore areas that are less familiar to them to broaden their exposure to other disciplines.

A prolific inventor, DeSimone holds more than 115 issued patents with more than 70 new patent applications pending, and he has published more than 240 peer-reviewed scientific articles.

Gecko-inspired Bandage

curiouscat — Fri, 25 Apr 2008 22:31:12 +0000

MIT creates gecko-inspired bandage

Drawing on some of the principles that make gecko feet unique, the surface of the bandage has the same kind of nanoscale hills and valleys that allow the lizards to cling to walls and ceilings. Layered over this landscape is a thin coating of glue that helps the bandage stick in wet environments, such as to heart, bladder or lung tissue. And because the bandage is biodegradable, it dissolves over time and does not have to be removed.
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Gecko-like dry adhesives have been around since about 2001 but there have been significant challenges to adapt this technology for medical applications given the strict design criteria required. For use in the body, they must be adapted to stick in a wet environment and be constructed from materials customized for medical applications. Such materials must be biocompatible, meaning they do not cause inflammation; biodegradable, meaning they dissolve over time without producing toxins; and elastic, so that they can conform to and stretch with the body’s tissues.
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When tested against the intestinal tissue samples from pigs, the nanopatterned adhesive bonds were twice as strong as unpatterned adhesives. In tests of the new adhesive in living rats, the glue-coated nanopatterned adhesive showed over a 100 percent increase in adhesive strength compared to the same material without the glue. Moreover, the rats showed only a mild inflammatory response to the adhesive, a minor reaction that does not need to be overcome for clinical use.

Among other advantages, the adhesive could be infused with drugs designed to release as the biorubber degrades. Further, the elasticity and degradation rate of the biorubber are tunable, as is the pillared landscape. This means that the new adhesives can be customized to have the right elasticity, resilience and grip for different medical applications.