Decoding Sweat...

New wearable sensors developed by scientists at UC Berkeley can provide real-time measurements of sweat rate and electrolytes and metabolites in sweat. (Credit: Bizen Maskey, Sunchon National University)

Topics: Biophysics, Biotechnology, Microfluidics, Nanotechnology, Research

A new scalable, high-throughput fabrication process that makes use of roll-to-roll printing and laser cutting can produce wearable sweat sensors rapidly and reliably and on a large scale. The devices, which can almost instantly detect and analyse electrolytes, metabolites and other biomolecules contained in sweat, could be employed in real-world applications and not just as laboratory prototypes.

Analyzing sweat is a non-invasive way to monitor a range of biomolecules, from small electrolytes to metabolites and hormones and larger proteins that come from deeper in the body. Indeed, sweat sensing has already been used to medically diagnose diseases like cystic fibrosis and autonomic neuropathy and to assess fluid and electrolyte balance in endurance athletes.

Traditional sweat sensors collect sweat from the body at different times and then analyse it. This means that the devices can’t be used to detect real-time changes in sweat composition – during physical activity, for example, or to monitor glucose levels in diabetic patients. Wearable sensors, which make use of flexible and hybrid electronics, overcome this problem by allowing for in-situ sweat measurements with real-time feedback. However, it is still difficult to reliably make sweat sensor components (including microfluidic chip and sensing electrodes) in large quantities and with good reproducibility.

Wearable patches could ‘decode’ sweat, Belle Dumé, Physics World

Speaking of Superheros...

Pauline Jennings, UC Berkeley
Courtesy of PolyPEDAL Lab, UC Berkeley

Topics: Biology, Biophysics, Nanotechnology

Notes:
1. Gecko Nanotechnology, Berger, Michael, Royal Society of Chemistry, Nano Werk dot com
2. Gecko adhesion: evolutionary nanotechnology, Autumn, Kellar; Gravish, Nick, The Royal Society Publishing

Animals famous for walking up walls can also use a combination of techniques to race across water.

The flat-tailed house gecko can not only stick to walls and glide through the air, but also run on water, a new study finds. This discovery of the combination of techniques the reptile uses to race across water could one day lead to robots capable of the same feats, researchers said.

The flat-tailed house gecko (Hemidactylus platyurus) is a common pet reptile native to southern and Southeast Asia. Not only can bristles on its toes help it climb walls and hang from ceilings, but it can glide with the aid of its webbed feet and skin flaps. "They're kind of like superheroes -- every time you look at them, they can do more things," said study senior author Robert Full, an integrative biologist at the University of California, Berkeley.

The newfound talent of this species was discovered by study co-author Ardian Jusufi, a biophysicist now at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, when he was in a rain forest in Singapore and saw the geckos skidding across puddles to escape predators. Lab experiments with these reptiles found they could run up to nearly a meter per second over 8 centimeters of water, faster than the swimming speeds of many aquatic creatures, including ducks, muskrats, juvenile alligators and marine iguanas. They could also easily switch to dashing across solid ground or scampering up a wall.

How Geckos Run on Water, Charles Q. Choi, Inside Science

Biomorphs...

Graphene-glass bimorphs can be used to fabricate numerous micron-scale 3-D structures.
CORNELL UNIVERSITY

Topics: Biophysics, Chemistry Nanotechnology, Robotics

A team of physicists from Cornell University in the US has developed electricity-conducting, environment-sensing, shape-changing robots the size of a human cell.

The robots – described in the journal Proceedings of the National Academy of Sciences – are made from atomically thin layers of graphene and glass. Known as biomorphs, the tiny machines bend when exposed to stimuli including heat, chemical reactions or electricity. They can transform in a fraction of a second from two dimensional planes into complex three-dimensional forms such as tetrahedra and cubes.

Team member Paul McEuen says the biomorphs are designed as carriers for even smaller, but potentially very powerful, bits of photonic, electronic or chemical kit.

“We are trying to build what you might call an 'exoskeleton' for electronics,” he says. “Right now, you can make little computer chips that do a lot of information-processing, but they don't know how to move or cause something to bend.”

Super-strong cell-size origami robots are coming, Andrew Masterson, Cosmos Magazine

Tagging...

Conceptual illustration by Yuen Yiu, staff writer
Image credits:
zhouxuan12345678 via flickr/CC BY-SA 2.0

Topics: Biology, Biophysics, Biotechnology, Consumer Electronics, Nanotechnology

Electronics small enough to fit inside cells may one day help scientists track individual cells and monitor their behavior in real time, a new study finds. These new devices could help analyze diseases from their origins in single cells, researchers said.

The new electronics are microscopic radio-frequency identification tags, which are essentially bar codes that can be read from a distance.

An RFID tag usually consists of an antenna connected to a microchip. A nearby reader known as a transceiver can emit electromagnetic signals at the tags, and the tags can respond with what data it has stored, such as its identity, when and where it was made, how to best store and handle it, and so on. Many RFID tags do not have batteries -- instead, they rely on the energy in the signals from the transceivers.

These tags are already being used in many applications today, including key cards, toll passes, library books and many other items, but the typical RFID tags are millimeters to centimeters in size. The new microscopic tags in comparison are only 22 microns wide each, or roughly one-fifth the average diameter of a human hair, making them the smallest known RFID tags, the researchers said. They detailed their findings online July 26 in the journal Physical Review Applied.

Tiny Electronic Tags Could Fit Inside Cells, Charles Q. Choi, Inside Science

Transparency...

Does the brain behave like a spin glass? (Courtesy: Shutterstock / Phonlamai Photo)

Topics: Biology, Biophysics, Neuroscience, Particle Physics

Spin-glass-like states that occur in models of neural networks can provide important insights into states of low and high brain activity that have been observed in mammals. That is the claim of a team of theoretical biophysicists in Spain who are the first to show that disordered states in neurological networks could have a functional role in living brains.

In familiar magnetic materials such as ferromagnets, the interaction between individual spin magnetic moments causes all of the spins to point in the same direction of magnetization. In spin-glass states, the interaction between spins does not allow individual spins to point in the same direction as their neighbours. This leads to "frustration", whereby no direction of magnetization exists and the spins point in random directions.

Brains are not magnetic systems and their working cells – neurons – do not resemble magnetic moments, but mathematically they behave in a similar manner. This is because neurons also have a binary variable – firing or not firing – which is similar to the up or down quantum states of spin. Neurons are also linked by synapses in a way that is similar to how magnetic spins interact with each other. As a result, a neural network in which all of the neurons are firing (or not firing) is similar to a magnetic material in which all of the spins are all pointing up (or down).

Physics World: Spin glass provides insight into brain activity, Michael Allen

Intrinsic Disorder...

Ricardo Bessa for Quanta Magazine

Topics: Biology, Biochemistry, Biophysics, Research

Proteins work like rigid keys to activate cellular functions — or so everyone thought. Scientists are discovering a huge number of proteins that shape-shift to do their work, upending a century-old maxim of biology.

Structure equals function: If there’s one thing we all learned about proteins in high school biology, that would be it. According to the textbook story of the cell, a protein’s three-dimensional shape determines what it does — drive chemical reactions, pass signals up and down the cell’s information superhighway, or maybe hang molecular tags onto DNA. For more than a century, biologists have thought that the proteins carrying out these functions are like rigid cogs in the cell’s machinery.

Of course, exceptions would occasionally crop up. A scientist might bump into a protein that performed its functions perfectly well yet didn’t have rigid structures. Most researchers chalked these cases up to experimental error, or dismissed them as insignificant outliers.

More recently, however, biologists have begun paying attention to these shapeshifters. Their findings are tearing down the structure-function dogma.

Proteins are chains of strung-together amino acids, and recent studies estimate that up to half of the total amino acid sequence that makes up proteins in humans doesn’t fold into a distinct shape. (While some of the proteins that make up this total are unstructured from end to end, others contain long unstructured regions side-by-side with structured ones.) “Partly, people didn’t realize how big that number was, and that’s why they ignored it,” said Julie Forman-Kay, a biochemist at the Hospital for Sick Children and the University of Toronto. “And partly they just didn’t know what to think of it.”

This fluidity — dubbed “intrinsic disorder” — endows proteins with a set of superpowers that structured proteins don’t have. Folded proteins tend to bind to their targets firmly, like a key in a lock, at just one or two spots, but their more stretched-out wiggly cousins are like molecular Velcro, attaching lightly at multiple locations and releasing with ease. This quick-on-quick-off binding’s effect in the cell is huge: It allows intrinsically disordered proteins — or IDPs, for short — to receive and respond to a slew of molecular messages simultaneously or in rapid succession, essentially positioning them to serve as cellular messaging hubs, integrating these multiple signals and switching them on and off in response to changes in the cell’s environment and to keep cellular processes ticking along as they should.

Quanta Magazine: The Shape-Shifting Army Inside Your Cells
Alla Katsnelson

Lasers, Nerves and Magnetic Fields...

Image source: Technology Review

Topics: Biology, Biophysics, Electrical Engineering, Electromagnetism, Quantum Mechanics

TECHNOLOGY REVIEW: Physicists have worked out how to measure the magnetic fields generated by single nerves from outside the body and at room temperature.

Biologists have known that nerves produce and respond to electrical signals since the 18th century, when Luigi Galvani discovered that the muscles in a frog’s leg twitch when stimulated by a spark.

However, the systematic study of the electrical signals that nerves produce had to wait until the early 20th century for the development of sensitive electrical recording equipment such as the cathode ray oscilloscope.

This development revolutionized the understanding of nervous function. The ways nerves conduct signals can be a powerful indicator for diseases such as multiple sclerosis and can even detect certain types of intoxication.

And yet the method has some drawbacks. For example, measuring electrical signals in nerves by inserting a needle-like electrode is somewhat invasive, and the mere act of attaching an electrode to a nerve can change the signal, making the results hard to interpret. So neuroscientists have long hoped for a noninvasive technique that could do the job instead.

That may be about to happen thanks to the work of Kasper Jensen at the University of Copenhagen in Denmark and a few pals who have developed a way to easily measure the magnetic fields associated with electrical signals in nerves. The technique could pave the way for a new generation of diagnostic tools for spotting diseases linked to nervous function and for understanding the basic function of nerves.

Physics arXiv:
Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity
Kasper Jensen, Rima Budvytyte, Rodrigo A. Thomas, Tian Wang, Annette Fuchs, Mikhail V. Balabas, Georgios Vasilakis, Lars Mosgaard, Thomas Heimburg, Søren-Peter Olesen, Eugene S. Polzik

Sticky DNA...

The cells in this microscope image were arranged in three dimensions using a new DNA-based technique. The cells stained green were meant to mimic cells that lead outgrowth during natural organ formation.

Topics: 3D Objects, Additive Manufacturing, Biology, Biophysics, Biomedicine, Computer Science, Mathematical Models

Before scientists can build human organs in the lab, they need to figure out how to build tissues that work like those in the body. A new method, in which DNA acts like Velcro that makes cells stick to each other, could help pave the way toward building functional tissues that might one day comprise organs.

The new method employs DNA strands, attached to the outside of individual cells, to cause them to stick to surfaces—or other cells—that feature complementary strands, and assemble into prescribed arrangements. The researchers use it to programmatically build tissues, layer by layer.

Other groups are taking a range of approaches toward building functional tissues (see “A Manufacturing Tool Builds 3-D Heart Tissue”). But compared to existing 3-D culture methods, the new one provides a greater level of control over “the ultimate tissue architecture,” argue its creators in a recent paper describing the research.

MIT Technology Review: Sticky DNA Could be the Key to Making Organs in a Lab, Mike Orcutt

Polonium-209...

Credit: Irvine/NIST

Scientists at the National Institute of Standards and Technology (NIST) have determined* that polonium-209, the longest-lived isotope of this radioactive heavy element, has a half-life about 25 percent longer than the previously determined value, which had been in use for decades.

The new NIST measurements could affect geophysical studies such as the dating of sediment samples from ocean and lake floors. They often employ Po-209 as a tracer. Because sediment cores are used for determining human impact on the environment over the past century, the new measurement could impact these studies as well as other environmental measurements and biological assays.

NIST: Polonium's Most Stable Isotope Gets Revised Half-Life Measurement, Chad Boutin

*R. Collé, R.P. Fitzgerald and L. Laureano-Perez. The half-life of 209Po: revisited. Journal of Physics G: Nuclear and Particle Physics 41 (2014) 105103, doi:10.1088/0954-3899/41/10/105103

Quantum Physics and Breathing...

Image source: Renewing All Things

(Inside Science) – Why don't we suffocate whenever we try to take a breath? An international team of scientists has used quantum mechanics – the science that usually deals with events at the level of the ultra-small – to solve this human-sized mystery.

Quantum mechanics has long proved its value in understanding such phenomena as the behavior of electrons and in classifying subatomic particles. But in recent years theorists have increasingly shown how it applies to all facets of life, large and small.

The new research, led by Cédric Weber of Kings College, London and reported in the journal Proceedings of the National Academy of Sciences, confirms that point.

"This work," said team member David O'Regan, a physicist at Ireland's Trinity College, Dublin, "helps to illustrate the fact that quantum-mechanical effects, which may sometimes be viewed as somehow very exotic or only relevant under extreme conditions, are at play in the day-to-day regimes where biology, chemistry, and materials science operate."

The paper's titled: "Renormalization of myoglobin–ligand binding energetics by quantum many-body effects." That's a mouthful, I know but you're a sharp crowd knowing you've read this far.

Side note: this is the National Academy of Sciences, started March 3, 1863 by President Abraham Lincoln.

They use a technique - Density Functional Theory, or DFT, which won the Nobel Prize in Chemistry in 1998, and its extension Density Mean-Field Theory. Some excerpts:

"DFT has been the standard tool for simulating electronic properties of materials and molecules for a number of years," O'Regan said.

The team used the technique to study reactions between the iron atom inside myoglobin and a molecule of oxygen or carbon monoxide. These reactions involve electrostatics, the arrangement of electric charges in atoms and molecules. When the iron atom transfers negative electric charges to an oxygen or carbon monoxide molecule, it enables the molecule to attach itself to the entire myoglobin protein.

Unfortunately, the theory consistently predicted that carbon monoxide should bind to myoglobin much more readily than oxygen.

"Using DMFT, we showed that, in fact, close to one electron is transferred to the oxygen molecule," Cole explained. "This provides much greater electrostatic stabilization than previously thought. It means that our estimate of the relative binding of oxygen and carbon dioxide is now in excellent agreement with experiment."

The analysis revealed that an effect called entanglement plays a critical role in binding oxygen molecules to the protein. Entanglement is a quintessential characteristic of quantum mechanics that links pairs of electrons so strongly that they no longer act independently. The process also involves Hund's exchange, another quantum-mechanical property that previous simulations had ignored.

The research has potential uses beyond understanding the molecular basis of breathing. According to Cole, the better understanding of how molecules bind to iron-containing proteins could help the drug-development process and possibly facilitate the design of artificial photosynthesis devices that would capture and store energy from the sun.

Impact: Supplying oxygen to the International Space Station would be a good low-orbital beta test platform. We could terraform our own planet, that we seem determined to do with the burning of fossil fuels anyway - our photosynthesis devices could remove carbon dioxide from the atmosphere and supply us with oxygen as its byproduct - we kind of need that. If we could do that, settling the Moon, Mars or any other planet would be a lot simpler once we engineer faster propulsion systems than we have currently. On Earth, "Green Tech" could literally mean converting solar energy into chemical energy useful to us as farmed (as in food) or mined resources. These are inevitably a dwindling supply and the basis for our current inequality hierarchy and scarcity economics. Please read the rest of the article at the link for more information.

Inside Science: How Quantum Mechanics Helps Us Breathe, Peter Gwynne

Terahertz Pumping...

Source: Technology Review

TECHNOLOGY REVIEW: One of the more significant practical challenges currently occupying molecular biologists is to find better ways of identifying short strands of DNA. Called oligonucleotides, these strands of nucleotides are hugely useful in processes such as genetic testing, forensics and DNA amplification.

But identifying the strands is a somewhat laboured business. Almost every detection method relies on fluorescent dyes and markers that can be picked up by optical sensors providing a useful but indirect indication of the molecules that are present.

But molecular biologists would like a better system that measures the characteristics of the molecules involved and so provides direct evidence of the sequence of nucleotides. Indeed, various research teams are working on such systems, some with significant success.

Today, Andrey Chernev at St Petersburg Academic University in Russia and a few pals say they have invented an entirely new way of identifying oligonucleotides using terahertz radiation. “Our results demonstrate a new method for label-free, real-time oligonucleotide characterisation,” they say.

An oligonucleotide is a short single-stranded DNA or RNA molecule usually consisting of fewer than a hundred or so bases. The sequence of these bases determines the type of oligonucleotide. So the ideal detection mechanism would reveal this sequence.

Abstract

Our results demonstrate a new method for label-free, real-time oligonucleotide characterisation by their self-resonant modes, which are unique to their conformation and sequence. We anticipate that our assay will be used as a starting point for a more detailed investigation of the aforementioned mechanism, which can be used as a basis for oligonucleotide detection and analysis. Furthermore, this technique can be applied to improve existing modern genetics technologies.

Physics arXiv: DNA Detection By THz Pumping
Andrey L. Chernev, Nicolay T. Bagraev, Leonid E. Klyachkin, Anton K. Emelyanov, Michael V. Dubina

Cancer Fighting Nanoparticles...

Source: link below

Mesoporous silica (mSiO₂) can be used to carry anti-cancer drugs to tumour sites in mice. So say researchers at the University of Wisconsin−Madison in the US who have succeeded in making TRC105-conjugated mSiO₂ labelled with radioactive copper for the first time. TRC105 is a chimeric monoclonal antibody that binds to both human and mouse endoglin, or CD105 (a type I membrane glycoprotein found on endothelial cell surfaces).

mSiO₂ nanoparticles are a promising new category of drug delivery vehicle because they are biocompatible and non-toxic. Their surfaces can also be easily modified and their mesopores (which are around 2–3 nm across) can hold a significant amount of therapeutic molecules.

Successful anti-cancer drug delivery

In vivo tumour targeting experiments by Cai and colleagues clearly show that the ⁶⁴Cu-NOTA-mSiO₂-PEG-TRC105 accumulates at mouse breast tumour sites (known as "4T1") thanks to TRC105-mediated binding to CD105 in tumour blood vessels. As a proof of concept, they also demonstrated that they could successfully deliver the anti-cancer drug doxorubicin (DOX) in mice with 4T1 tumours by injecting DOX-loaded ⁶⁴Cu-NOTA-mSiO₂-PEG-TRC105 into the animals.

Nanotech Web: Silica nanoparticles deliver anti-cancer drugs

Growing Your Phototransistor...

TECHNOLOGY REVIEW: Chlorophyll is one of the most efficient light-absorbing materials known to science. It also happens to be remarkably stable and abundant beyond imagination.

Researchers studying ways to capture and exploit photons view the amazing capabilities of chlorophyll with green-eyed wonder. Indeed, they would dearly love to copy this extraordinary light-gathering ability.

But there may be a quick way of catching up. Instead of designing and making artificial materials that attempt to copy chlorophyll, researchers have begun to think about using this naturally-occurring material itself and attempting to bend it to their will.

Today, Shao-Yu Chen at the Institute of Atomic and Molecular Sciences in Taiwan and a few buddies reveal how they have incorporated chlorophyll into graphene transistors to make light-activated switches.

The new phototransistor design is relatively simple. It consists of two silver electrodes connected by a sheet of graphene. The graphene is then covered by a layer of chlorophyll using a method known as drop casting. This involves placing a drop of liquid containing chlorophyll on top of the graphene and letting it evaporate. This coats the graphene with a layer of chlorophyll.

Physics arXiv:
Biologically inspired graphene-chlorophyll phototransistors with high gain

Panspermia...

Panspermia (Greek: πανσπερμία from πᾶς/πᾶν (pas/pan) "all" and σπέρμα (sperma) "seed") is the hypothesis that life exists throughout the Universe, distributed by meteoroids, asteroids and planetoids. (Wikipedia)

So you won't think I just pulled the title out of...well, you know. Almost sounds like an old George Carlin skit...

Early Earth was not very hospitable when it came to jump starting life. In fact, new research shows that life on Earth may have come from out of this world.

Lawrence Livermore National Laboratory (LLNL) scientist Nir Goldman and Univ. of Ontario Institute of Technology colleague Isaac Tamblyn (a former LLNL postdoctoral researcher) found that icy comets that crashed into Earth millions of years ago could have produced life building organic compounds, including the building blocks of proteins and nucleobases pairs of DNA and RNA.

Comets contain a variety of simple molecules, such as water, ammonia, methanol and carbon dioxide, and an impact event with a planetary surface would provide an abundant supply of energy to drive chemical reactions.

"The flux of organic matter to Earth via comets and asteroids during periods of heavy bombardment may have been as high as 10 trillion kilograms per year, delivering up to several orders of magnitude greater mass of organics than what likely pre-existed on the planet," Goldman says.

Goldman's earlier work is based on computationally intensive models, which, in the past, could only capture 10 to 30 picoseconds of a comet impact event. However new simulations, developed on LLNL's supercomputers Rzcereal and Aztec, Goldman used much more computationally efficient models and was able to capture hundreds of picoseconds of the impacts—much closer to chemical equilibrium.

"As a result, we now observe very different and a wider array of hydrocarbon chemical products that, upon impact, could have created organic material that eventually led to life," Goldman says.

R&D: Life on Earth comes from out of this world

Your Brain on Science...

A. Haimovici et al., Phys. Rev. Lett. (2013)

Figure 1: (Left column) Functional magnetic resonance imaging (fMRI) experiments have revealed that the brain at rest is organized into several areas in which fluctuations of brain activities are correlated, so-called resting state networks (RSN). From top to bottom: Medial visual (VisM), lateral visual (VisL), auditory (Aud), and sensory-motor (SM) RSNs. (Right columns) Results from the work of Haimovici et al. [1] show that a simple model can reproduce the statistical properties of RSNs only if the model is tuned to criticality (at TC)

Neuroscience is at the brink of an unprecedented advance in obtaining instant, detailed maps of neuronal activity during higher brain functions such as object recognition and decision making. These maps will become possible thanks to a rapid cross fertilization among fields (molecular biology, optics, imaging, microfabrication processes, and nanotechnologies) and are considered crucial to make sense of the complex activities that emerge from the billions of neurons making trillions of connections that constitute the human brain. Relevant large-scale research projects are being carried out or are being planned internationally: the Human Connectome Project and BRAIN (Brain Research through Advancing Innovative Neurotechnologies) in the US, the Human Brain Project in Europe, and the Brainnetome project in China. The overarching goal of these large undertakings will be to explain how the brain functions, by acquiring and integrating detailed information on brain structure and its dynamical behavior. But will these endeavors succeed? Knowledge about fine structural details of the brain and observations of neuronal activities may not be sufficient if the emergence of forms of collective behavior is not properly captured. Writing in Physical Review Letters, Ariel Haimovichi, at the University of Buenos Aires in Argentina, and co-workers [1] beautifully exemplify how cooperative phenomena play a key role in determining brain dynamics, by showing that the brain in its resting state (i.e., when not performing an explicit task) is a system at criticality.

APS Viewpoint: The Critical Brain

Inner Space...

The actin fibers of a nerve cell's growing axon are shown in red - NIH

The cells of our bodies aren't just featureless bags of proteins. Many of them have distinctive shapes and structures that are essential to their function. Neurons, for example, extend processes away from their cell bodies for up to several feet. The lining of your intestines has a specialized surface for absorbing food. And when immune cells encounter an infected cell, they form a specialized surface that allows them to kill the infected cell without harming its neighbors.

To form all of these structures, the cell has to be internally specialized, with different regions having distinct sets of proteins and chemicals. But it's hard to study the processes that make one part of the cell different from another. Most of the tools we have are rather blunt and affect the whole cell equally. But researchers have reported a clever trick that lets them activate proteins in a specific location: stick them on a tiny magnetic bead, then move the bead around inside the cell.

Ars Technica: “Magnetogenetics” probes the inner space of a cell

Stealth Nanoparticles...

By binding to an immune system cell's receptor (grey), a man-made component (yellow) of a protein could prevent the body from getting rid of a therapeutic nanoparticle. DIEGO PANTANO

Small man-made peptides can help to sneak drug-bearing nanobeads past the ever-vigilant immune system, a group of US researchers has found.

To work effectively, drugs and imaging agents need to get to the diseased cells or tumours where they’re needed most. Although scientists are developing nanoparticles that help to deliver drugs to the right place, all therapeutic molecules face a deadly foe — the immune system. Its macrophages are designed to spot any intruding molecules in the blood and destroy them in a process called phagocytosis.

Researchers at the University of Pennsylvania in Philadelphia have now found a way to stop macrophages from destroying drug-bearing nanoparticles. They have designed and made a small segment of a crucial membrane protein called CD47, which is recognized by macrophages as being safe. This means that molecules that contain CD47 can get past macrophages and into blood cells.

Nature: Stealth nanoparticles sneak past immune system’s defences

Table-Top Protons...

Credit: Physics World - Lateral Dose

Proton therapy is used in the treatment of cancer and hopeful remission from the disease.

There is a significant difference between standard (x-ray) radiation treatment and proton therapy. If given in sufficient doses, x-ray radiation techniques will control many cancers. But, because of the physician's inability to adequately conform the irradiation pattern to the cancer, healthy tissues may receive a similar dose and can be damaged. Consequently, a less- than-desired dose is frequently used to reduce damage to healthy tissues and avoid unwanted side effects. The power of protons is that higher doses of radiation can be used to control and manage cancer while significantly reducing damage to healthy tissue and vital organs.¹

*****

A table-top proton accelerator for medical therapy could be one step closer thanks to work done by physicists in Germany. The team's system is based on a compact Ti:sapphire laser, which fires ultrashort light pulses at a diamond-like foil to produce bunches of protons with energies of around 5 MeV.

The team has shown that its device delivers radiation doses to biological cells that are similar to doses created by much larger conventional proton-therapy systems. The researchers say that the technique could also be used to study ultrafast processes in biology and chemistry.²

1. The National Association for Proton Therapy, Official Site
2. Pulsed lasers could make proton therapy more accessible, Physics World

DNA Origami...

TECHNOLOGY REVIEW: One of the most promising ways to capture, generate and manipulate photons is with tiny diamonds. The secret is to create nanodiamonds with a defect in their structure where a nitrogen atom has taken the place of a carbon.

Quantum physicists are particularly interested in these so-called nitrogen vacancies because they can capture, store and emit the quantum information that photons carry. What’s more, they do all this at room temperature. It is even possible to manipulate this information using magnetic and electric fields.

In short, nitrogen vacancies are important building blocks for for quantum computers.

But there’s a problem. It’s not hard to make individual nanodiamonds but it is extremely difficult to arrange them next to each other so that the quantum information they store can be processed.

Their idea is to bind nanodiamonds together with the required nanometre precision using biological molecules such as DNA and protein. What’s more, they say they’ve demonstrated the technique for the first time.

Physics arXiv: Self-assembling hybrid diamond-biological quantum devices

Slime Requiem...

We DID learn something from "Ghostbusters."

TECHNOLOGY REVIEW: Physarum polycephalum, better known as slime mold, is a single-celled creature that has attracted considerable attention in recent years for its ability to compute in unconventional ways. Various research groups have watched in barely disguised amazement as these single cells have solved mazes, recreated national motorway networks and even anticipated the timing of periodic events.

Now this extraordinary creature has added another skill to its box of tricks–the ability to make music, or at least to create sound in a controlled fashion.

To create a sound, Miranda and co used the signal from each electrode to control the frequency of an audio oscillator. With each electrode controlling a different range of frequencies, they then added the outputs from all the oscillators to create a complex sound that represents the activity of the Physarum.

Of course, this kind of mixing is rather arbitrary but Miranda and co are mainly interested in the sound production method. They say it is possible to control the electrical activity in different parts of the network of tubes by zapping it with light.

In a sense, this allows them to “play” the Physarum like a musical instrument.

Physics arXiv: Physicists Use Electrical Signals From Slime Mould to Make Music