Recognizing Your Protein, One Molecule At a Time

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Image: Hemoglobin

In the medical field, detection methods are king. There’s no better way to protect someone from disease or cancer than to know how to catch it early, in the least invasive way.

The Human Genome Project has already mapped out our genetic code, making it easier to study and pinpoint where harmful sequences may pop up. However, genes don’t directly interact with most of the processes in the body, they’re just the blueprints for the proteins that do.

Proteins are a bit trickier to analyze, since they can be insanely complex. There are twenty-one amino acids that make up the individaul building blocks of proteins. Those amino acids are strung together in chains called peptides, folded into three dimensions, and then possibly accessorized by other smaller proteins, fatty acids, or metallic ions. Most of the protein structure has no charge, expect for specific sites that are customized to interact with specific molecules.

Proteins can’t be replicated in mass like DNA and RNA can. Most labs use a molecule structure that the protein will latch onto, separating it from the original mixture. Then they take the sample of proteins and bombard it with x-rays. The image captured of the x-rays bouncing off the protein molecules reveals the structure. However, in order to perform this method successfully, you really need to know what you’re looking for beforehand.

Now, an easier and more straightforward way might be just over the horizon. A team at Arizona State University, led Stuart Lindsay, created a device that measures the unique electrical charge from each type of amino acid, one at a time. A charged “tail” attaches to the end of the protein and pulls it through the a hole opening just nanometers thick (called a “nanopore”) and two electrodes record the charges of the molecules that pass by. The researchers were able to distinguish between different amino acids, whole proteins that are mirror images of each other, and proteins with or without accessory molecules attached.

Lindsay and his team are now working on a a fast and cost-effective prototype for clinical use.

Check out the video of the nanopore device below:

 

Video Credit: Biodesign Institute at Arizona State University

When the Heart Doesn’t Need a Makeover

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Sometimes, you’re body’s responses aren’t in your best interest. After a heart attack, the body releases higher levels of enzymes that eat away at some of the proteins lining the heart’s walls. At the beginning, this releases some of the pressure caused by the blockage. Over time, however, the enzymes can go on a frenzy, making the heart weaker and less efficient. It effectively changes the shape of the heart, called “ventricle remodeling.”

Because the enzymes target the specific areas around the blockage, a greater discrepancy between the pressure in the right and left sides of the heart forms. This can lead to other heart problems, such as mismatched rhythm and blood flow dynamics between the two sides.

Researchers at University of Pennsylvania have found a way to keep these enzymes in line. They created molecules in their lab called “protease inhibitors” that interact with the enzymes and stop them from working.

Here’s a graphic on how protein inhibition works:

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They packed the inhibitors in layers of hydrogel that can be injected straight into the heart. The hydrogel, similar to the chemical in diapers that absorbs urine, is great at both holding onto chemicals in a compact way and interfacing with organic tissue. In fact, the hydrogel imitates how tissue store inhibitors produced by the body.

The dance between different enzymes and inhibitors happens all over the body and creates a feedback loop that regulates bodily functions, such as breaking down food and repairing cells. The researchers didn’t want their inhibitors to disrupt other parts of the body, so they focused on a localized approach, instead of putting the inhibitors into a pill, and hoping that they would make their way from the digestive system to the heart.

The hydrogel layers are held together by specific molecular bonds called “crosslinks.” The researchers customized the crosslinks so that they would only be broken down by these enzymes. The inhibitor, hiding behind the crosslink, then latches onto the enzyme, disabling it. The right balance of inhibitors and enzymes makes sure that the effect of remodeling is carefully controlled.

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Hydrogel interaction with enzyme

The researchers have already tested this mechanism on animals, showing that pigs treated with the hydrogel after heart attack retain most of their heart walls’ thickness and the same amount of blood it previously pumped.

This same approach can also be used for other applications, like osteoarthritis, to stop enzymes from destroying cartilage.

To check out the paper, click here: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat3922.html

Credit Photo 1: Dreamstime

Credit Photo 2: Wikipedia

Perovskite Solar Cells Have a Light Source Alter Ego

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Set your phasers to ‘eco-friendly.’ A new type of solar cell material can double as a light or even a laser.

We’ve been hearing about the promise of solar cells for decades. And that promise has slowly unraveled - bit by bit, advancements in solar cells construction has improve. Cells today convert 20% of sunlight hitting them into electricity, and it’s taken us over twenty years to get here.

However, a thin film material called perovskite is becoming an unexpected solar cell rising star. Within two years of working with it for solar cells, researchers were able to increase it’s efficiency to 17%, on the cusp of rivaling standard solar cells, which are made of silicon. They’re also easier to manufacture.  

But perovskites have another trick up their sleeve. Not only can they turn light into electricity, but they can turn that electricity back into light later on - up to 70% of it.

When light hits a solar cell, the material’s electrons get excited and escape their original locations orbiting around their atoms, leaving behind an empty space called a ‘hole.’ The elecrons (with a negative charge) and the holes (with a postive charge) flow in different directions, creating a current. In perovskite, electrons and holes can recombine later on, emitting the same light wavelength. Even though electrons and holes in semiconductors can combine to an extent, they don’t reach anywhere near the stability and efficiency of perovskite. The ‘lifetime’ of the charges between separation and recombination are thousands of times longer than other materials.

Researchers also created a laser out of the perovskite film by placing a mirror on either side of it. Its ability to be used as a laser makes it a prime candidate for digital communication applications. It also hints at even greater perovskite cell efficiency in the future.  

Photo Credit: Winton Programme for the Physics of Sustainability

Spinning the Diamond Age of Computers

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Diamonds aren’t only good for engagements, but are valuable components in the tech and nano worlds. In supercomputers, diamonds are the ideal material to draw heat given off by hardware out of the system, and diamonds with built-in glitches can store quantum information longer than anything else.

Now they may have a new future application: as nanowire circuits to carry information within computers. However, unlike the wires we use today, diamond wires could carry spin down their length. Spin is the angular momentum of electrons (and other particles) that has two directions, up and down. Magnets or electrical currents can manipulate the spin in electrons to store information on digital devices.    

This new feature in diamonds was just demonstrated by physicists at Ohio State University. Within the wire, the electrons didn’t move, but the alignment of spin direction passed between them, like a wave.  In order for the wire to transmit spin, the diamond structure had to be ‘doped,’ or adulterated with a single nitrogen atom, similar to the glitch in the quantum information storage device. The reseachers measured the spin states using a nanometer-sized magnet on the tip of an Atomic Force Microscope. The attraction and repulsion between the magnet and the diamond’s electrons let the reseachers map out the spins along the wire and how long they lasted. They measured each section of the wire as the spin flowed through it.

When they measured the middle of the wire, something surprising happened. The spins in the middle lasted half the amount of time as the spin on the ends, essentially flowing the spin into ‘spin reservoirs’ at either end. This is the first time anyone has seen this behavior with spin, and has the potential to turn everything we know about this quantum property on its head.

The push forward to use spin as an alternative to electric current (called ‘spintronics’) can provide us with even smaller, more compact wires that expend less waste heat. However, we may not be seeing diamond wires in commercial products for a while. The wire needed to be cooled down to -4520F to work and be detectable, and it will be a long road until researchers can exploit a similar wire at room temperature.

Regenerating “Skin” of the Future

Skin is one of those marvels of nature that we take for granted everyday. It’s flexible, self-repairing, and filled with thousands of nerve endings. It’s like a giant touch screen that you can bend without ruining.

Previously, no man-made material matched all these properties so well. However, Zhenan Bao and her team at Stanford have now just created a material that self-heals and conducts electricity. The material is a flexible plastic embedded with nickel nanoparticles. It can sense pressure, stretching, and twisting. The researchers can tune the material to the level of electrical conductivity desired.

When you slice it with a scalpel, all you practically have to do is hold both opened parts of the material for 15 seconds, and 90% of the electrical conductivity will be restored. After 10 minutes, the material will be completely healed. You can keep on making the same exact cut, and it will heal without any of its properties weakening. That’s practically superhero territory.

This material would push forward advancements in robots, prosthetics, and even repair electrical damage inside the walls of buildings. Bao is now working to make the material more elastic and transparent.    

Bao’s research group at Stanford

Self-healing “skin” paper in Nature Nanotechnology

Food Safety and Nano Webinar by Consumer International

Wondering how nanotech might affect food? Well then, you’re just in luck! In about an hour, Consumer International’s webinar at 10am (Eastern US time) today will bring you the latest on these developments and how it relates to you, with expert scientist from on food, consumer safety, and the environment.

To go to the webinar page, click here: http://www.consumersinternational.org/news-and-media/events/2012/11/nanotech-webinar 

I know that this announcement is very last minute, so if I can, I’ll link to the webinar recording later on.

Neural Prosthetics

Injured nerves. Dying brain cells. Loss of function. There is nothing more debilitating than your own electrical circuitry going haywire. When part of these connections is compromised, there can be permanent damage and unspeakable pain.

Luckily, Joseph Corey at the University of Michigan is developing a new platform to repair or replace damage nerves. They use biodegradable plastic spun into nanofibers to support and guide nerve growth. The nerve cells mistake it for a nerve, and start wrapping around it.

There are a number of nerve research and therapy treatments that could emerge from this advancement: One of the major applications is multiple sclerosis (MS) treatment. The researchers were able to discover the best diameter of nanofiber to allow the growth of a protective nerve covering called myelin. MS destroys the myelin covering, and the researchers can use the nanofibers to study myelin depletion and, even one day, reverse it. Another application that Corey and his team are working on is using the nanofibers as a neural guinea pig. They incorporate different molecules to the fibers to see what leads to poor or unconnected nerves. Lastly, the researcher put genetically engineered stem cells onto the nanofibers and found that the cell grew into nerve cells more easily than without this support, making it a potential for nerve implants.

Even though these advancements are still at the early stages, this may, in the future, help thousands of people suffering from brain, spinal cord, or nerve damage and allow them to regain function.   

How Does the Nanoworld Slide?

The nanoscale plays by its own rules. Even something as simple as friction— everyone has experienced a creaky door or a slippery hallway— can be completely mysterious in this tiny realm. If you are trying to make a motor or gear on the nanoscale, what do you need to take into account? Remember, you also have molecular and atomic forces as well.

Luckily, two Italian researchers, Nicola Manini and Erio Tosatti, have come up with a solution. They used a single-layer nanocrystal filled with tiny charged particles as a model. As the crystal slid across a set of crossed laser beams, they were able to successfully simulate the speeds and spacing of the particles at different angles of the crystal, analyzing the dynamics of the forces involved. Moreover, they suggested a way to harness the energy that the crystal loses from friction.

Here’s a link to the paper they published (WARNING: Paywall!):

http://www.pnas.org/content/109/41/16429.abstract

And the paper’s supplemental info:

http://www.pnas.org/content/suppl/2012/09/27/1213930109.DCSupplemental

Prof. Tosatti’s Website:

https://sites.google.com/site/tosattierio/

Going All Carbon

Sustainability doesn’t just mean tapping into renewable energy and lowering your carbon footprint. It includes using cheap and abundant (and hopefully efficient) materials to do so. No one knows this better than Dr. Zhenan Bao and her research team at Stanford University, who have put together the first all-carbon solar cell.

There are three types of solar cells available: bulky silicon panels, thin film cells like Indium Tin Oxide (what iPhone screens are made out of), and coatings that apply straight onto surfaces. The carbon cell is of the latter kind. Even though it’s spreadable, the coat has three different layers on the nanoscale: graphene and carbon nanotubes for the electrodes, and buckyballs, the futuristic soccer ball-shaped carbon molecule, to convert light into electricity. Other types of cells use expensive or rare materials for at least one component of the cell, however, with Bao’s cell, carbon is literally everywhere.

Unfortunately, the all-carbon cell has a pretty terrible efficiency, absorbing less that 1% of the total light that hits it. Bao and her team are currently trying to find ways to improve the cell, such as stacking the nanomaterials in a better way and looking at other carbon molecules, which would absorb a wider band of wavelengths.

Credit: Mark Schwartz/Stanford University

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