How To Forge Graphene In 3D Shape

The wonder material graphene gets many of its handy quirks from the fact that it exists in two dimensions, as a sheet of carbon only one atom thick. But to actually make use of it in practical applications, it usually needs to be converted into a 3D form. Now, researchers have developed a new and relatively simple way to do just that, using lasers to “forge” a three-dimensional pyramid out of graphene.

This isn’t the first time graphene has been given an extra dimension. In 2015, researchers from the University of Illinois molded graphene into 3D structures by layering it onto shaped substrates, and early this year MIT scientists found that tubes of the stuff could be shaped into 3D coral-like structures 10 times stronger than steel but just five percent as dense. Rice University researchers have also recently made graphene foam and reinforced it with carbon nanotubes.

But this new technique, developed by researchers in Finland and Taiwan, might be an easier and faster method to make 3D graphene. By focusing a laser onto a fine point on a 2D graphene lattice, the graphene at that spot is irradiated and bulges outwards. A variety of three-dimensional shapes can be made by writing patterns with the laser spot, with the height of the shape controlled by adjusting the irradiation dose at each particular point.

The team illustrated that technique by deforming a sheet of graphene into a 3D pyramid, standing 60 nm high. That sounds pretty tiny, but it’s 200 times taller than the graphene sheet itself.

We call this technique optical forging, since the process resembles forging metals into 3D shapes with a hammer,” says Mika Pettersson, co-author of the study. “In our case, a laser beam is the hammer that forges graphene into 3D shapes. The beauty of the technique is that it’s fast and easy to use; it doesn’t require any additional chemicals or processing. Despite the simplicity of the technique, we were very surprised initially when we observed that the laser beam induced such substantial changes on graphene. It took a while to understand what was happening.”

The researchers initially assumed that the laser had “doped” the graphene, introducing impurities into the material, but after further examination they found that wasn’t the case.

When we first examined the irradiated graphene, we were expecting to find traces of chemical species incorporated into the graphene, but we couldn’t find any,” comments Wei Yen Woon, co-author of the study. “After some more careful inspections, we concluded that it must be purely structural defects, rather than chemical doping, that are responsible for such dramatic changes on graphene.

The scientists explain that the optically forged graphene is structurally sound, highlighting its potential for building 3D architectures out of the material for a wide range of applications. In this form, the graphene has different electronic and optical properties from its 2D counterpart.

The research was published in the journal Nano Letters.

Source: Academy of Finland

Nanoparticles Eradicate PreCancerous Cells In The Liver

According to the American Cancer Society, more than 700,000 new cases of liver cancer are diagnosed worldwide each year. Currently, the only cure for the disease is to surgically remove the cancerous part of the liver or transplant the entire organ. However, an international study led by University of Missouri (MU) – School of Medicine  researchers has proven that a new minimally invasive approach targets and destroys precancerous tumor cells in the livers of mice and invitro human cells.

liver cancer

The limitations when treating most forms of cancer involve collateral damage to healthy cells near tumor sites,” said Kattesh Katti, PhD, Curators’ Professor of Radiology and Physics at the MU School of Medicine and lead author of the study. “For more than a decade we have studied the use of nanotechnology to test whether targeted treatments would reduce or eliminate damage to nearby healthy cells. Of particular interest has been the use of green nanotechnology approaches pioneered here at MU that use natural chemical compounds from plants.”

The study was conducted in the United States and Egypt, and it involved the use of gold nanoparticles encapsulated by a protective stabilizer called gum Arabic. The nanoparticles were introduced to the livers of mice intravenously and were heated with a laser through a process known as photothermal therapy.

Gum Arabic is a natural gum made of the hardened sap from acacia trees,” said Katti, who also serves as director of the MU Institute of Green Nanotechnology and Professor of Medical Research at the MU School of Medicine. “It is FDA-approved for human consumption and is primarily used in the food industry as an additive. It also promotes adhesion of gold nanoparticles engineered to attract to precancerous and malignant cells – which are much more susceptible to lower levels of heat than healthy cells. Once the nanoparticles travel and adhere to cancerous cells, they are heated to a temperature that destroys them but leaves healthy tissue unaffected.”

Katti’s team studied a total of 224 mice. Half were identified as having precancerous cells in their livers. The other half had normal liver tissue. Outside of the control group, the mice received either an intravenous injection of gum Arabic alone or gum Arabic-encapsulated gold nanoparticles with or without laser therapy.

The administration of gum Arabic, gold nanoparticles and photothermal therapy caused no change to healthy tissue, which confirmed the safe use of these treatments,” Katti said. “However, the use of gum Arabic-encapsulated nanoparticles combined with photothermal therapy resulted in the targeted eradication of the precancerous cells and their genetic code in both our mice model and the human invitro cell model we developed for this study.”

Source: http://medicine.missouri.edu/

Gentle Cancer Treatment Using Nanoparticles

Cancer treatments based on laser irradiation of tiny nanoparticles that are injected directly into the cancer tumor are working and can destroy the cancer from within. Researchers from the Niels Bohr Institute and the Faculty of Health Sciences at the University of Copenhagen  (Denmark) have developed a method that kills cancer cells using nanoparticles and lasers. The treatment has been tested on mice and it has been demonstrated that the cancer tumors are considerably damaged.

mouse with cancer treatment

 
The drawing shows a mouse with a cancerous tumor on its hind leg. The nanoparticles are injected directly into the tumor, which is then flashed with near infrared laser light. Near infrared laser light penetrates through the tissue well and causes no burn damage
 

 

Traditional cancer treatments like radiation and chemotherapy have major side affects, because they not only affect the cancer tumors, but also the healthy parts of the body. A large interdisciplinary research project between physicists at the Niels Bohr Institute and doctors and human biologists at the Panum Institute and Rigshospitalet has developed a new treatment that only affects cancer tumors locally and therefore is much more gentle on the body. The project is called Laser Activated Nanoparticles for Tumor Elimination (LANTERN). The head of the project is Professor Lene Oddershede, a biophysicist and head of the research group Optical Tweezers at the Niels Bohr Institute at the University of Copenhagen in collaboration with Professor Andreas Kjær, head of the Cluster for Molecular Imaging, Panum Institute.

After experimenting with biological membranes, the researchers have now tested the method on living mice. In the experiments, the mice are given cancer tumors of laboratory cultured human cancer cells“The treatment involves injecting tiny nanoparticles directly into the cancer. Then you heat up the nanoparticles from outside using lasers. There is a strong interaction between the nanoparticles and the laser light, which causes the particles to heat up. What then happens is that the heated particles damage or kill the cancer cells,” explains Lene Oddershede.

The results are published in the scientific journal, Scientific Reports.

How To Triple Perovskite Solar Cells Efficiency

A new type of two-dimensional-layered perovskite developed by Northwestern University, Los Alamos National Laboratory and Rice University researchers will open up new horizons for next-generation stable solar-cell devices and new opto-electronic devices such as light-emitting diodes, lasers and sensors.

The research team has tweaked its crystal production method and developed a 2-D perovskite with outstanding stability and more than triple the material’s previous power conversion efficiency. This could bring perovskite crystals closer to use in the burgeoning solar power industry.

flipping crystals

  • Crystal orientation has been a puzzle for more than two decades, and this is the first time we’ve been able to flip the crystal in the actual casting process,” said Hsinhan Tsai, a Rice graduate student at Los Alamos working with senior researcher and study lead co-author Aditya Mohite.

This is our breakthrough, using our spin-casting technique to create layered crystals whose electrons flow vertically down the material without being blocked, mid layer, by organic cations,” Tsai said.

Northwestern scientists created the two-dimensional material used by the researchers at Los Alamos in the new solar cells. Mercouri G. Kanatzidis, the Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, and Costas Stoumpos, a postdoctoral fellow in Kanatzidis’ group, had been exploring an interesting 2-D material that orients its layers perpendicular to the substrate.

This breakthrough resulted from a very strong synergy between our institutions — the materials design team at Northwestern that designed and prepared high-quality samples of the materials and showed they are promising and the Los Alamos team’s excellent skills in making solar cells and optimizing them to high performance,” Kanatzidis said.

Wanyi Nie, a Los Alamos co-author on the paper, noted, “The new 2-D perovskite is both more efficient and more stable, both under constant lighting and in exposure to the air, than the existing 3-D organic-inorganic crystals.

The study was published July 6 by the journal Nature.

Source: http://www.lanl.gov/

Nano-Robots Enter Living Cells

Researchers have developed the world’s tiniest engine – just a few billionths of a metre in size – which uses light to power itself. The nanoscale engine, developed by researchers at the University of Cambridge, could form the basis of future nano-machines that can navigate in water, sense the environment around them, or even enter living cells to fight disease. The prototype device is made of tiny charged particles of gold, bound together with temperature-responsive polymers in the form of a gel. When the ‘nano-engine’ is heated to a certain temperature with a laser, it stores large amounts of elastic energy in a fraction of a second, as the polymer coatings expel all the water from the gel and collapse. This has the effect of forcing the gold nanoparticles to bind together into tight clusters. But when the device is cooled, the polymers take on water and expand, and the gold nanoparticles are strongly and quickly pushed apart, like a spring.

nano-motor

It’s like an explosion,” said Dr Tao Ding from Cambridge’s Cavendish Laboratory, and the paper’s first author. “We have hundreds of gold balls flying apart in a millionth of a second when water molecules inflate the polymers around them.
We know that light can heat up water to power steam engines,” said study co-author Dr Ventsislav Valev, now based at the University of Bath. “But now we can use light to power a piston engine at the nanoscale.”

The results are reported in the journal PNAS.

Source: http://www.cam.ac.uk/

How To Break The Brain Barrier To Kill Cancer

Using a laser probe, neurosurgeons at Washington University School of Medicine in St. Louis have opened the brain’s protective cover, enabling them to deliver chemotherapy drugs to patients with a form of deadly brain cancer. In a pilot study, 14 patients with glioblastoma – the most common and aggressive type of brain cancer – underwent minimally invasive laser surgery to treat a recurrence of their tumors. Heat from the laser is known to kill brain tumor cells but, unexpectedly, the researchers found that the technology can penetrate the blood-brain barrier.

laser breaks brain barrierCLICK ON THE IMAGE TO ENJOY THE VIDEO

The laser treatment kept the blood-brain barrier open for four to six weeks, providing us with a therapeutic window of opportunity to deliver chemotherapy drugs to the patients,” said co-corresponding author Eric C. Leuthardt, MD, a Washington University professor of neurosurgery who treats patients at Barnes-Jewish Hospital. “This is crucial because most chemotherapy drugs can’t get past the protective barrier, greatly limiting treatment options for patients with brain tumors. We are closely following patients in the trial,” said Leuthardt, who also is a Siteman Cancer Center member. “Our early results indicate that the patients are doing much better on average, in terms of survival and clinical outcomes, than what we would expect. We are encouraged but very cautious because additional patients need to be evaluated before we can draw firm conclusions.

The study is published online Feb. 24 in the journal PLOS ONE.

Source: https://medicine.wustl.edu/

Arrhythmia: How To Prevent Heart Attack

A new nanoparticle developed by University of Michigan researchers could be the key to a targeted therapy for cardiac arrhythmia, a condition that causes the heart to beat erratically and can lead to heart attack and stroke. The disease affects more than 4 million Americans and causes more than 750,000 hospitalizations and 130,000 deaths per year in the U.S. alone.

The new treatment uses nanotechnology to precisely target and destroy the cells within the heart that cause cardiac arrhythmia. In studies conducted on rodents and sheep, the U-M team found that the treatment successfully kills the cells that cause cardiac arrhythmia while leaving surrounding cells unharmed. Cardiac arrhythmia is caused by malfunctions in a certain type of heart muscle cell, which normally helps regulate the heartbeat. Today, the disease is usually treated with drugs, which can have serious side effects. It can also be treated with a procedure called cardiac ablation that burns away the malfunctioning cells using a high-powered laser that’s threaded into the heart on a catheter. The laser also damages surrounding cells, which can cause artery damage and other serious problems.

The U-M team, led by Dr. Jérôme Kalifa, a cardiologist and assistant professor of internal medicine, and Raoul Kopelman, Professor of Chemistry, set out to target and destroy the cells with a far more precise technique that uses low-level red light illumination instead of a high-power laser. Widely used today to treat cancer, the technique requires doctors to mark unwanted cells with a chemical that makes them sensitive to low-level red light. The red light then destroys the marked cells while leaving surrounding tissue unharmed.

cardiologyMicroscopy photos show a cardiac myocyte cell (top) and an attached fibroblast cell (bottom) in a rat heart, after the injection of the newly developed nanoparticle. In the second frame, red light has been applied. The red coloring indicates that the myocyte, which causes cardiac arrhythmia, has been killed, while the fibroblast remains unharmed.

The great thing about this treatment is that it’s precise down to the level of individual cells,” Kopelman said. “Drugs spread all over the body and high-power lasers char the tissue in the heart. This treatment is much easier and much safer.”

The findings are detailed in a new study published in the journal Science Translational Medicine.

Source: http://ns.umich.edu/

How To Produce Massively And Easily Solar Panels

Nanoscale materials feature extraordinary, billionth-of-a-meter qualities that transform everything from energy generation to data storage. But while a nanostructured solar cell may be fantastically efficient, that precision is notoriously difficult to achieve on industrial scales. The solution may be self-assembly, or training molecules to stitch themselves together into high-performing configurations.

Now, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have developed a laser-based technique to execute nanoscale self-assembly with unprecedented ease and efficiency.

solarPanelWe design materials that build themselves,” said Kevin Yager, a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN). “Under the right conditions, molecules will naturally snap into a perfect configuration. The challenge is giving these nanomaterials the kick they need: the hotter they are, the faster they move around and settle into the desired formation. We used lasers to crank up the heat.”

Source: http://www.bnl.gov/

3D Hologram From Pop-Up Floating Display

Moving holograms like those used in 3D science fiction movies such as Avatar and Elysium have to date only been seen in their full glory by viewers wearing special glasses.
Now researchers at Swinburne University of Technology (Australia) have shown the capacity of a technique using graphene oxide and complex laser physics to create a pop-up floating display without the need for 3D glasses. Graphene is a two dimensional carbon material with extraordinary electronic and optical properties that offers a new material platform for next-generation nanophototonic devices.

Through a photonic process without involving heat or a change in temperature, the researchers were able to create nanoscale pixels of refractive index – the measure of the bending of light as it passes through a medium – of reduced graphene oxide. This is crucial for the subsequent recording of the individual pixels for holograms and hence naked eye 3D viewing.
3D graphene
If you can change the refractive index you can create lots of optical effects,” Director of Swinburne’s Centre for Micro-Photonics, Professor Min Gu, said.
Our technique can be leveraged to achieve compact and versatile optical components for controlling light. We can create the wide angle display necessary for mobile phones and tablets.

Source: http://www.nature.com/

How to “Grow” Billions Of Light Dots Directly On Chips

Researchers from the University of California, Santa Barbara (UCSB), in collaboration with the DARPA, succeeded to grow lasers directly on microchips, a breaktrhrough that will enable the mass-production of inexpensive and robust microsystems that exceed the performance capabilities of current technologies.

Defense systems for instance, such as radar, communications, imaging and sensing payloads rely on a wide variety of microsystems devices. These diverse devices typically require particular substrates or base materials and different processing technologies specific to each application, preventing the integration of such devices into a single fabrication process. Integration of these technologies, historically, has required combining one microchip with another, which introduces significant bandwidth and latency limitations as compared to microsystems integrated on a single chip. Although many photonic components can now be fabricated directly on silicon, realizing an efficient laser source on silicon has proven to be very difficult.
Now, the engineers at UCSB showed it was possible to “grow” or deposit successive layers of indium arsenide material directly on silicon wafers to form billions of light-emitting dots known as “quantum dots.” This method of integrating electronic and photonic circuits on a common silicon substrate promises to eliminate wafer bonding, and has application in numerous military and civilian electronics where size, weight, power and packaging/assembly costs are critical.
laser on chipsDARPA’s Electronic-Photonic Heterogeneous Integration (E-PHI) program has successfully integrated billions of light-emitting dots on silicon to create an efficient silicon-based laser. The Defense Advanced Research Projects Agency (DARPA) is an agency of the United States Department of Defense responsible for the development of new technologies for use by the military.
This method of integrating electronic and photonic circuits on a common silicon substrate promises to eliminate wafer bonding, and has application in numerous military and civilian electronics where size, weight, power and packaging/assembly costs are critical“.“It is anticipated that these E-PHI demonstrator microsystems will provide considerable performance improvement and size reduction versus state-of-the-art technologies,” said Josh Conway, DARPA program manager for E-PHI. “Not only can lasers be easily integrated onto silicon, but other components can as well, paving the way for advanced photonic integrated circuits with far more functionality than can be achieved today.

Source: http://www.darpa.mil/

Handheld Scanner To Remove Brain Tumor

Cancerous brain tumors are notorious for growing back despite surgical attempts to remove them — and for leading to a dire prognosis for patients. But scientists are developing a new way to try to root out malignant cells during surgery so fewer or none get left behind to form new tumors. The method, reported in the journal ACS Nano, could someday vastly improve the outlook for patients.
laser pointerA handheld device that resembles a laser pointer could someday help surgeons remove all of the cells in a brain tumor
Moritz F. Kircher and colleagues at Memorial Sloan Kettering Cancer Center point out that malignant brain tumors, particularly the kind known as glioblastoma multiforme (GBM), are among the toughest to beat. Although relatively rare, GBM is highly aggressive, and its cells multiply rapidly. Surgical removal is one of the main weapons doctors have to treat brain tumors. The problem is that currently, there’s no way to know if they have taken out all of the cancerous cells. And removing extra material “just in case” isn’t a good option in the brain, which controls so many critical processes. The techniques surgeons have at their disposal today are not accurate enough to identify all the cells that need to be excised. So Kircher’s team decided to develop a ew method to fill that gap.

The researchers used a handheld device resembling a laser pointer that can detectRaman nanoprobes” with very high accuracy. These nanoprobes are injected the day prior to the operation and go specifically to tumor cells, and not to normal brain cells. Using a handheld Raman scanner in a mouse model that mimics human GBM, the researchers successfully identified and removed all malignant cells in the rodents’ brains. Also, because the technique involves steps that have already made it to human testing for other purposes, the researchers conclude that it has the potential to move readily into clinical trials. Surgeons might be able to use the device in the future to treat other types of brain cancer, they say.

Source: http://www.acs.org/

Laser + Neuroscience + Nanotechnology To Attack Parkinson’s

Researchers have Combined physics and neurobiology to tackle Parkinson’s Disease. Professor Keshav Dani from the Okinawa Institute of Science and Technology (OIST) – Japan – Graduate University’s Femtosecond Spectroscopy Unit and Neurobiology Research Unit, along with collaborators at the University of Otago, New Zealand are using lasers, nanotechnology and neuroscience to develop a new, versatile drug delivery system. In a new article in Scientific Reports, the researchers describe their work using a laser to release a neurochemical, the function of which is impaired in Parkinson’s Disease, in a controlled and repeatable manner.


Currently, we administer drugs in a systemic way and tissues or organs that do not need the drug receive it, leading to unwanted side effects. A good example of this is in chemotherapy, which is toxic not only to the intended target cancer cells, but also to healthy tissue

An exciting new area of research for a cure or therapy for many diseases is targeted drug delivery. Recent advances in nanotechnology and biology are opening up the possibilities in targeted drug delivery, where researchers can release drugs or compounds in a specific tissue or even individual cells, which would allow the drug to reach only its intended target. In their recent paper, OIST researchers describe a method to encapsulate a drug in a shell of lipids, or fat, called a liposome, and modulate the release of the drug using a pulse from a laser.

Source: http://www.oist.jp/