nanoparticles

6

LIQUID SCULPTURES with FERROFLUID
SPIKED WITH MAGNETIC NANOPARTICLES

(Image: Linden Gledhill/Cognisys - on Flickr)

Ferrofluids are colloidal mixtures - magnetic nanoparticles suspended evenly throughout a carrier liquid.

When placed in a magnetic field, the suspended particles cause the entire fluid to become strongly magnetized. In these images a small drop of ferrofluid is placed within a magnetic field created by a neodymium iron-boron rare-earth magnet.

The peaks and troughs result as the magnet tries to pull the liquid along its field lines.

Text based on a story in New Scientist 8 November 2010

Images from Linden and Shirlie Gledhill’s Flickr pages - check out Linden’s other great macro photography.

Nanoparticles for Converting Windows to Solar Cells

Sandra Casillas from the Technological Institute of La Laguna (ITL), in the north of Mexico, has managed to patent 20 projects, and an example of her work is the design of two Tandem cells that turns windows into a solar panel capable of capturing up to eight volts per square meter of light and allows to recharge electronics. It is also transparent, allowing visibility.

[read more]

Bee venom contains a potent toxin called melittin that can poke holes in the protective envelope that surrounds HIV, and other viruses. Large amounts of free melittin can cause a lot of damage. Indeed, in addition to anti-viral therapy, the paper’s senior author, Samuel A. Wickline, MD, the J. Russell Hornsby Professor of Biomedical Sciences, has shown melittin-loaded nanoparticles to be effective in killing tumor cells.

The new study shows that melittin loaded onto these nanoparticles does not harm normal cells. That’s because Hood added protective bumpers to the nanoparticle surface. When the nanoparticles come into contact with normal cells, which are much larger in size, the particles simply bounce off. HIV, on the other hand, is even smaller than the nanoparticle, so HIV fits between the bumpers and makes contact with the surface of the nanoparticle, where the bee toxin awaits.

— 

Nanoparticles loaded with bee venom kill HIV

If this study holds a lot of scientific weight, that’s fucking amazing. Nanoparticles have been showing nothing but great promises for the field of virology it seems.

Scientists Made Color-Changing Paint Out of Gold Nanoparticles

Something unexpected happened when scientists at the University of California, Riverside, started stringing together nanoparticles of gold. 

The gold wasn’t golden anymore. It changed colors. 

“When we see these gold particles aggregate, we find out they have very, very beautiful blue colors,” chemist Yadong Yin told me. That bright blue would dissipate like a sunset—morphing into purple, then red—when scientists warped the strings, breaking apart the nanoparticles.

The finding was one of those happy scientific accidents that turns into something bigger. “So after we found out the reason why they show blue colors and what the structure was, then we started to think what kind of use they could have,” Yin said.

What Yin and his colleagues came up with: Sensors made of gold nanoparticles that change colors as you press on them. Think of it as a Hypercolor—those color-changing T-shirts all the cool kids had in the ‘90s—but for touch instead of heat.

Read more. [Image: Reuters]

Optogenetics without the genetics

One of the greatest revolutions in neuroscience over the past few decades has been the discovery of optogenetics, a method that allows scientists to control neural activity with light. It involves genetically engineering neurons to express a light-sensitive protein, which was first discovered in algae. A flash of light can then precisely activate or deactivate these neurons. The ability to control the activity of individual neurons without damaging the cells has allowed scientists to understand the brain in new ways, affect behavior, and, believe it or not, even implant false memories. However, its reliance on genetic modification means that its use is limited to a few model organisms.

Now, a new study shows that light can be used to activate normal, non-genetically modified neurons. How? Through the use of targeted gold nanoparticles. The technique, described by a team of scientists led by Francisco Bezanilla, PhD, Lillian Eichelberger Cannon Professor of biochemistry and molecular biology at the University of Chicago, represents a significant technological advance. Importantly, it offers potential advantages over current optogenetic methods, including possible use in the development of therapeutics toward diseases such as macular degeneration.

“This is effectively optogenetics without genetics,” Bezanilla said. “Many optogenetic experimental designs can now be applied to completely normal tissues or animals, greatly extending the scope of these research tools and possibly allowing for new therapies involving neuronal photostimulation.”

Bezanilla and his colleagues have previously shown that normal, non-genetically modified neurons can be activated by heat generated from pulses of infrared light. But this method lacked specificity and can damage cells. To improve the technique, they focused on gold nanoparticles – spheres only 20 nanometers in diameter, more than 300 times smaller than a human blood cell.

When stimulated with visible light, spherical gold nanoparticles absorb and convert light energy into heat. This heating effect, which is most efficient using green light, can activate unmodified neurons. However, nanoparticles must be extremely close to a cell to produce any effect. Since the nanoparticles diffuse quickly, or get washed away in a neuron’s immediate environment, their efficacy is short-lived.

To get nanoparticles to stick, Bezanilla and his team coupled them to a synthetic molecule based on Ts1, a scorpion neurotoxin, which binds to sodium channels without blocking them. Neurons treated with Ts1-coupled nanoparticles in culture were readily activated by light. Untreated neurons were non-responsive. Importantly, treated neurons could still be stimulated even after being continuously washed for 30 minutes, indicating that the nanoparticles were tightly bound to the cell surface. This also minimized potentially harmful elevated temperatures, as excess nanoparticles were washed away.

Neurons treated with Ts1-coupled nanoparticles could be stimulated repeatedly with no evidence of cell damage. Some individual neurons, targeted with millisecond pulses of light, produced more than 3,000 action potentials over the span of thirty minutes, with no reduction in efficacy. In addition to cultured cells, Ts1-coupled nanoparticles were tested on complex brain tissue using thin slices of mouse hippocampus. In these experiments, the researchers were able to activate groups of neurons and then observe the resulting patterns of neural activity.

“The technique is easy to implement and elicits neuronal activity using light pulses. Therefore, stimulating electrodes are not required,” Bezanilla said. “Furthermore, with differently-shaped nanoparticles it can work in near-infrared as well as in visible wavelengths, which has many practical advantages in living animals. Thus far, most optogenetic tools have been limited to visible wavelengths.”

Optogenetics without the genetics

Light can be used to activate normal, non-genetically modified neurons through the use of targeted gold nanoparticles, report scientists from the University of Chicago and the University of Illinois at Chicago. The new technique, described in the journal Neuron on March 12, represents a significant technological advance with potential advantages over current optogenetic methods, including possible use in the development of therapeutics toward diseases such as macular degeneration.

“This is effectively optogenetics without genetics,” said study senior author Francisco Bezanilla, PhD, Lillian Eichelberger Cannon Professor of biochemistry and molecular biology at the University of Chicago. “Many optogenetic experimental designs can now be applied to completely normal tissues or animals, greatly extending the scope of these research tools and possibly allowing for new therapies involving neuronal photostimulation.”


A group of neurons. Credit: EPFL/Human Brain Project       

Nanoparticles Found to Change Size

If you’ve ever eaten from silverware or worn copper jewelry, you’ve been in a perfect storm in which nanoparticles were dropped into the environment, say scientists at the Univ. of Oregon. Since the emergence of nanotechnology, researchers, regulators and the public have been concerned that the potential toxicity of nano-sized products might threaten human health by way of environmental exposure. Now, with the help of high-powered transmission electron microscopes, chemists captured never-before-seen views of miniscule metal nanoparticles naturally being created by silver articles such as wire, jewelry and eating utensils in contact with other surfaces. It turns out, researchers say, nanoparticles have been in contact with humans for a long, long time.

Read more: http://www.laboratoryequipment.com/news-Nanoparticles-Arent-New-102511.aspx

Aurora

While it looks like the aurora borealis (northern lights) dancing in a crystal ball, this image was actually created by assembling plastic nanoparticles within a micro-sized droplet surrounded by transparent silicon oil. The fluorescent bluish and greenish glow come from the reflection and scattering of the light within the microsphere. By using microscale structures to confine light, scientists may discover potential applications in optical switches and interconnects, sensors and displays.

More technically: Dark field optical microscopic image of a photonic microsphere by self-assembly of polystyrene nanoparticles (130 nm) in a emulsion droplet in between two glass substrates.

Credit: Yongxing Hu/Argonne National Laboratory

Nanosponges soak up toxins released by bacterial infections and venom

Engineers at the University of California, San Diego have invented a “nanosponge” capable of safely removing a broad class of dangerous toxins from the bloodstream – including toxins produced by MRSA, E. coli, poisonous snakes and bees. These nanosponges, which thus far have been studied in mice, can neutralize “pore-forming toxins,” which destroy cells by poking holes in their cell membranes. Unlike other anti-toxin platforms that need to be custom synthesized for individual toxin type, the nanosponges can absorb different pore-forming toxins regardless of their molecular structures. In a study against alpha-haemolysin toxin from MRSA, pre-innoculation with nanosponges enabled 89 percent of mice to survive lethal doses.

Administering nanosponges after the lethal dose led to 44 percent survival.

The team, led by nanoengineers at the UC San Diego Jacobs School of Engineering, published the findings in Nature Nanotechnology April 14.

“This is a new way to remove toxins from the bloodstream,” said Liangfang Zhang, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and the senior author on the study. “Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralize toxins caused by a wide range of pathogens, including MRSA and other antibiotic resistant bacteria,” said Zhang. The work could also lead to non-species-specific therapies for venomous snake bites and bee stings, which would make it more likely that health care providers or at-risk individuals will have life-saving treatments available when they need them most.

The researchers are aiming to translate this work into approved therapies. “One of the first applications we are aiming for would be an anti-virulence treatment for MRSA. That’s why we studied one of the most virulent toxins from MRSA in our experiments,” said “Jack” Che-Ming Hu, the first author on the paper. Hu, now a post-doctoral researcher in Zhang’s lab, earned his Ph.D. in bioengineering from UC San Diego in 2011.

Aspects of this work will be presented April 18 at Research Expo, the annual graduate student research and networking event of the UC San Diego Jacobs School of Engineering.

Nanosponges as Decoys

In order to evade the immune system and remain in circulation in the bloodstream, the nanosponges are wrapped in red blood cell membranes. This red blood cell cloaking technology was developed in Liangfang Zhang’s lab at UC San Diego. The researchers previously demonstrated that nanoparticles disguised as red blood cells could be used to deliver cancer-fighting drugs directly to a tumor. Zhang also has a faculty appointment at the UC San Diego Moores Cancer Center.

Red blood cells are one of the primary targets of pore-forming toxins. When a group of toxins all puncture the same cell, forming a pore, uncontrolled ions rush in and the cell dies.

The nanosponges look like red blood cells, and therefore serve as red blood cell decoys that collect the toxins. The nanosponges absorb damaging toxins and divert them away from their cellular targets. The nanosponges had a half-life of 40 hours in the researchers’ experiments in mice. Eventually the liver safely metabolized both the nanosponges and the sequestered toxins, with the liver incurring no discernible damage.

Each nanosponge has a diameter of approximately 85 nanometers and is made of a biocompatible polymer core wrapped in segments of red blood cells membranes.

Zhang’s team separates the red blood cells from a small sample of blood using a centrifuge and then puts the cells into a solution that causes them to swell and burst, releasing hemoglobin and leaving RBC skins behind. The skins are then mixed with the ball-shaped nanoparticles until they are coated with a red blood cell membrane.

Just one red blood cell membrane can make thousands of nanosponges, which are 3,000 times smaller than a red blood cell. With a single dose, this army of nanosponges floods the blood stream, outnumbering red blood cells and intercepting toxins.

Based on test-tube experiments, the number of toxins each nanosponge could absorb depended on the toxin. For example, approximately 85 alpha-haemolysin toxin produced by MRSA, 30 stretpolysin-O toxins and 850 melittin monomoers, which are part of bee venom.

In mice, administering nanosponges and alpha-haemolysin toxin simultaneously at a toxin-to-nanosponge ratio of 70:1 neutralized the toxins and caused no discernible damage.

One next step, the researchers say, is to pursue clinical trials.

Image: Engineers at the University of California, San Diego have invented a “nanosponge” capable of safely removing a broad class of dangerous toxins from the bloodstream, including toxins produced by MRSA, E. Coli, poisonous snakes and bees. The nanosponges are made of a biocompatible polymer core wrapped in a natural red blood cell membrane.

Credit: Zhang Research Lab

watch the video here

Magnetic nanoparticles could allow brain stimulation without wires

Researchers at MIT have developed a method to stimulate brain tissue using external magnetic fields and injected magnetic nanoparticles – a technique allowing direct stimulation of neurons, which could be an effective treatment for a variety of neurological diseases, without the need for implants or external connections.

The research, conducted by Polina Anikeeva, an assistant professor of materials science and engineering, graduate student Ritchie Chen, and three others, has been published in the journal Science.

Previous efforts to stimulate the brain using pulses of electricity have proven effective in reducing or eliminating tremors associated with Parkinson’s disease, but the treatment has remained a last resort because it requires highly invasive implanted wires that connect to a power source outside the brain.

“In the future, our technique may provide an implant-free means to provide brain stimulation and mapping,” Anikeeva says.

Ritchie Chen, Gabriela Romero, Michael G. Christiansen, Alan Mohr, and Polina Anikeeva. Wireless magnetothermal deep brain stimulation. Science, March 2015 DOI: 10.1126/science.1261821

Images show calcium ion influx into neurons as a result of magnetothermal excitation with alternating magnetic fields in the presence of magnetic nanoparticles.Credit: Courtesy of the researchers

Nanoparticle Fights Cancer in Two Ways

Univ. of New South Wales chemical engineers have synthesized a new iron oxide nanoparticle that delivers cancer drugs to cells while simultaneously monitoring the drug release in real time.

The result, published online in the journal ACS Nano, represents an important development for the emerging field of theranostics – a term that refers to nanoparticles that can treat and diagnose disease.

Read more: http://www.laboratoryequipment.com/news/2013/10/nanoparticle-fights-cancer-two-ways

(Image caption: A cancer cell containing the nanoparticles. The nanoparticles are coloured green, and have entered the nucleus, which is the area in blue. Credit: M Welland)

“Trojan horse” treatment could beat brain tumours

A smart technology which involves smuggling gold nanoparticles into brain cancer cells has proven highly effective in lab-based tests.

A “Trojan horse” treatment for an aggressive form of brain cancer, which involves using tiny nanoparticles of gold to kill tumour cells, has been successfully tested by scientists.

The ground-breaking technique could eventually be used to treat glioblastoma multiforme, which is the most common and aggressive brain tumour in adults, and notoriously difficult to treat. Many sufferers die within a few months of diagnosis, and just six in every 100 patients with the condition are alive after five years.

The research involved engineering nanostructures containing both gold and cisplatin, a conventional chemotherapy drug. These were released into tumour cells that had been taken from glioblastoma patients and grown in the lab.

Once inside, these “nanospheres” were exposed to radiotherapy. This caused the gold to release electrons which damaged the cancer cell’s DNA and its overall structure, thereby enhancing the impact of the chemotherapy drug.

The process was so effective that 20 days later, the cell culture showed no evidence of any revival, suggesting that the tumour cells had been destroyed.

While further work needs to be done before the same technology can be used to treat people with glioblastoma, the results offer a highly promising foundation for future therapies. Importantly, the research was carried out on cell lines derived directly from glioblastoma patients, enabling the team to test the approach on evolving, drug-resistant tumours.

The study was led by Mark Welland, Professor of Nanotechnology at the Department of Engineering and a Fellow of St John’s College, University of Cambridge, and Dr Colin Watts, a clinician scientist and honorary consultant neurosurgeon at the Department of Clinical Neurosciences. Their work is reported in the Royal Society of Chemistry journal, Nanoscale.

“The combined therapy that we have devised appears to be incredibly effective in the live cell culture,” Professor Welland said. “This is not a cure, but it does demonstrate what nanotechnology can achieve in fighting these aggressive cancers. By combining this strategy with cancer cell-targeting materials, we should be able to develop a therapy for glioblastoma and other challenging cancers in the future.”

To date, glioblastoma multiforme (GBM) has proven very resistant to treatments. One reason for this is that the tumour cells invade surrounding, healthy brain tissue, which makes the surgical removal of the tumour virtually impossible.

Used on their own, chemotherapy drugs can cause a dip in the rate at which the tumour spreads. In many cases, however, this is temporary, as the cell population then recovers.

“We need to be able to hit the cancer cells directly with more than one treatment at the same time” Dr Watts said. “This is important because some cancer cells are more resistant to one type of treatment than another. Nanotechnology provides the opportunity to give the cancer cells this ‘double whammy’ and open up new treatment options in the future.”

In an effort to beat tumours more comprehensively, scientists have been researching ways in which gold nanoparticles might be used in treatments for some time. Gold is a benign material which in itself poses no threat to the patient, and the size and shape of the particles can be controlled very accurately.

When exposed to radiotherapy, the particles emit a type of low energy electron, known as Auger electrons, capable of damaging the diseased cell’s DNA and other intracellular molecules. This low energy emission means that they only have an impact at short range, so they do not cause any serious damage to healthy cells that are nearby.

In the new study, the researchers first wrapped gold nanoparticles inside a positively charged polymer, polyethylenimine. This interacted with proteins on the cell surface called proteoglycans which led to the nanoparticles being ingested by the cell.

Once there, it was possible to excite it using standard radiotherapy, which many GBM patients undergo as a matter of course. This released the electrons to attack the cell DNA.

While gold nanospheres, without any accompanying drug, were found to cause significant cell damage, treatment-resistant cell populations did eventually recover several days after the radiotherapy. As a result, the researchers then engineered a second nanostructure which was suffused with cisplatin.

The chemotherapeutic effect of cisplatin combined with the radiosensitizing effect of gold nanoparticles resulted in enhanced synergy enabling a more effective cellular damage. Subsequent tests revealed that the treatment had reduced the visible cell population by a factor of 100 thousand, compared with an untreated cell culture, within the space of just 20 days. No population renewal was detected.

The researchers believe that similar models could eventually be used to treat other types of challenging cancers. First, however, the method itself needs to be turned into an applicable treatment for GBM patients. This process, which will be the focus of much of the group’s forthcoming research, will necessarily involve extensive trials. Further work needs to be done, too, in determining how best to deliver the treatment and in other areas, such as modifying the size and surface chemistry of the nanomedicine so that the body can accommodate it safely.

Sonali Setua, a PhD student who worked on the project, said: “It was hugely satisfying to chase such a challenging goal and to be able to target and destroy these aggressive cancer cells. This finding has enormous potential to be tested in a clinical trial in the near future and developed into a novel treatment to overcome therapeutic resistance of glioblastoma.”

Welland added that the significance of the group’s results to date was partly due to the direct collaboration between nanoscientists and clinicians. “It made a huge difference, as by working with surgeons we were able to ensure that the nanoscience was clinically relevant,” he said. “That optimises our chances of taking this beyond the lab stage, and actually having a clinical impact.”

2

Glowing space mice show where quantum dots lodge

They may look like something captured by the Hubble telescope, but these mice are revealing more about their inner space than what’s in outer space. The fluorescent speckles, spots and clouds marking their bodies are nanoparticles lodged within their skin and rendered visible with ultraviolet light.

Nanoparticles are increasingly being used in water treatment, food packaging, cosmetics and as pesticides, prompting concerns about the health effects of long-term exposure. Yet until now, it has been difficult to quantify the accumulation of nanoparticles within tissues, without destroying them.

These images show mice injected with nanoparticles called quantum dots – light-sensitive, semiconducting particles just a few nanometres in diameter. The particles can be seen though the skin when the mice are exposed to UV light using a technique called inductively coupled plasma atomic emission spectroscopy.

Warren Chan of the University of Toronto in Canada found that the concentration of these particles in the skin directly correlates with both the injected dose and their accumulation in other organs. His team hopes that this discovery could be used to better predict how nanoparticles behave in the body.

Journal reference: Nature, DOI: 10.1038/ncomms4796

Image Credit: Edward A. Sykes & Qin Dai

4

Researchers Magnetically Control Nanoparticles Inside Cells

Scientists have figured out a way to make tiny magnetic particles that they can watch and manipulate inside the body. 

An international team of researchers built nanoparticles whose core is made of magnetic materials encapsulated in a uniform fluorescent coating.  The breakthrough means that researchers can watch the movement of the particles inside an individual cell and move them around that cell by applying a magnetic field. 

See the video below.

Keep reading

Nanoparticles to kill cancer cells with heat

Heat may be the key to killing certain types of cancer, and new research from a team including National Institute of Standards and Technology (NIST) scientists has yielded unexpected results that should help optimize the design of magnetic nanoparticles that can be used to deliver heat directly to cancerous tumors.

When combined with other treatments such as radiotherapy or chemotherapy, heat applied directly to tumors helps increase the effectiveness of those types of treatments, and it reduces the necessary dose of chemicals or radiation.

This is where magnetic nanoparticles come in. These balls of iron oxide, just a few tens of nanometers in diameter, heat up when exposed to a powerful magnetic field. Their purpose is to bring heat directly to the tumors. Materials research, performed in part at the NIST Center for Neutron Research (NCNR), revealed magnetic behavior that proved counterintuitive to the scientific team—a finding that will affect which particles are chosen for a particular treatment.

More information: “Internal magnetic structure of nanoparticles dominates time-dependent relaxation processes in a magnetic field.” Advanced Functional Materials. Published online June 2, 2015. DOI: 10.1002/adfm.201500405

Iron oxide nanoparticles with a neatly-stacked internal structure (left) need a stronger magnetic field than expected to heat up, while those with a more haphazard arrangement heat up more quickly, even under a weak field. The findings, which run contrary to expectations, could affect which nanoparticles are chosen to treat certain types of cancer. Credit: NIST