Luminescence switchable carbon nanodots follow intracellular trafficking and drug delivery


Tiny carbon dots have, for the first time, been applied to intracellular imaging and tracking of drug delivery involving various optical and vibrational spectroscopic-based techniques such as fluorescence, Raman, and hyperspectral imaging. Researchers have demonstrated, for the first time, that photo luminescent carbon nanoparticles can exhibit reversible switching of their optical properties in cancer cells.

‘Caged’ non-fluorescent carbon dot enters the cancer cell, loses its caging and lights up.

Tiny carbon dots have, for the first time, been applied to intracellular imaging and tracking of drug delivery involving various optical and vibrational spectroscopic-based techniques such as fluorescence, Raman, and hyperspectral imaging. Researchers from the University of Illinois at Urbana-Champaign have demonstrated, for the first time, that photo luminescent carbon nanoparticles can exhibit reversible switching of their optical properties in cancer cells.

“One of the major advantages of these agents are their strong intrinsic optical sensitivity without the need for any additional dye/fluorophore and with no photo-bleaching issues associated with it,” explained Dipanjan Pan, an assistant professor of bioengineering and the leader of the study. “Using some elegant nanoscale surface chemistry, we created a molecular ‘masking’ pathway to turn off the fluorescence and then selectively remove the mask leading to regaining the brightness.

“Using carbon dots for illuminating human cells is not new. In fact, my laboratories, and several other groups around world, have shown that these tiny dots represent a unique class of luminescent materials with excellent biocompatibility, degradability, and relatively facile access to large-scale synthesis in comparison to other popular luminescent materials such as quantum dots,” added Pan.

And, the entire process of is highly controlled and can be observed in living cells as they reported in the group’s study, “Macromolecularly ‘Caged’ Carbon Nanoparticles for Intracellular Trafficking via Switchable Photoluminescence,” appearing in the Journal of the American Chemical Society.

“We can apply this technique for intracellular trafficking by means of switchable photo-luminescence in mammalian cells in vitro, wherein the endocytic membrane-abundant anionic amphiphilic molecules participates in the ‘de-caging’ process,” stated Pan. “The carbon dots, each measuring less than 50 nanometers in diameter, are derived from agave nectar and are highly luminescent. The in situ nanoscale chemical exchange further probed into the mechanistic understanding of the origin of carbon luminescence and indicated that it is primarily a surface phenomenon.

“This can be reversibly turned on and off by a simple counter-ionic nanoscale chemistry,” Pan said. “These results can become the basis for new and interesting designs for carbon-based materials for intracellular imaging probing cellular function and to study other biological processes.”

Has Nanotechnology Already Reached Its Limit?


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What’s the Latest Development?

Professor Mike Kelly at Cambridge University’s Centre for Advanced Photonics and Electronics has stunned a budding nanotechnology industry by saying that structures with a diameter of three nanometres or less cannot be mass-produced. “This statement raises a major question concerning the billions of dollars that are poured into nanotechnology each year in the hope that the latest technology developed in the lab can make the transition to a manufactured product on the market,” according to Phys Org.

What’s the Big Idea?

Nanotechnology is built on the ability to control and manipulate matter at the atomic and molecular level and has already had far reaching applications including helping drugs to be delivered into patients’ bodies, improving food packaging and increasing the efficiency of solar panels. It is a budding industry that, given recent success in the laboratory—the 2010 Nobel Prize was given to two scientists for their experiments with graphene, an extremely tough one-atom-think nanostructure—holds large commercial potential.

Acne spot treatment: Latest in nanotechnology, transdermal drug delivery to take on an old problem


Acne, a scourge of adolescence, may be about to meet its ultra high-tech match. By using a combination of ultrasound, gold-covered particles and lasers, researchers have developed a targeted therapy that could potentially lessen the frequency and intensity of breakouts, relieving acne sufferers the discomfort and stress of dealing with severe and recurring pimples.

The particles are delivered into the sebaceous gland by the ultrasound, and are heated by the laser. The heat deactivates the gland.

Acne, a scourge of adolescence, may be about to meet its ultra high-tech match. By using a combination of ultrasound, gold-covered particles and lasers, researchers from UC Santa Barbara and the private medical device company Sebacia have developed a targeted therapy that could potentially lessen the frequency and intensity of breakouts, relieving acne sufferers the discomfort and stress of dealing with severe and recurring pimples.

“Through this unique collaboration, we have essentially established the foundation of a novel therapy,” said Samir Mitragotri, professor of chemical engineering at UCSB.

Pimples form when follicles get blocked by sebum, an oily, waxy substance secreted by sebaceous glands located adjacent to the follicle. Excretion of sebum is a natural process and functions to lubricate and waterproof the skin. Occasionally, however, the openings of the follicles (pores) get blocked, typically by bits of hair, skin, dirt or other debris mixed in with the sebum. Overproduction of sebum is also a problem, which can be caused by hormones or medications. Changes in the skin, such as its thickening during puberty, can also contribute to follicle blockage. Whatever the cause, the accumulating sebum harbors bacteria, which results in the inflammation and local infection that we call acne.

The new technology builds on Mitragotri’s specialties in targeted therapy and transdermal drug delivery. Using low-frequency ultrasound, the therapy pushes gold-coated silica particles through the follicle into the sebaceous glands. Postdoctoral research associate Byeong Hee Hwang, now an assistant professor at Incheon National University, conducted research at UCSB.

“The unique thing about these particles is that when you shine a laser on them, they efficiently convert light into heat via a process called surface plasmon resonance,” said Mitragotri. This also marks the first time ultrasound, which has been proved for years to deliver drugs through the skin, has been used to deliver the particles into humans.

These silica and gold particles are exceedingly tiny — about a hundredth of the width of a human hair — but they are key to the therapy. Once the particles are deposited in the target areas, lasers are aimed at them and, because the gold shells are designed specifically to interact with the near-infrared wavelengths of the lasers, the light becomes heat. The heated particles essentially cause deactivation of the sebaceous glands. The sebum, pore-blocking substances and particles are excreted normally.

“If you deactivate these overproducing glands, you’re basically treating the root cause of the acne,” said Mitragotri.

According to the research, which is published in the Journal of Controlled Release, this protocol would have several benefits over conventional treatments. Called selective photothermolysis, the method does not irritate or dry the skin’s surface. In addition, it poses no risk of resistance or long-term side effects that can occur with antibiotics or other systemic treatments.

“It’s highly local but highly potent as well,” Mitragotri said of the treatment. “I think this would be beneficial in addressing the concerns regarding other, conventional treatments.” According to Mitragotri, this photothermolysis method is particularly suited to patients with advanced, severe or difficult-to-treat acne. The research has gone from concept to clinical trials in a relatively short amount of time. However, other more long-term elements of this therapy have yet to be studied, such as the extent of follicular damage, if any; what the most effective and beneficial parameters of this treatment may be; and what contraindications exist.

Nanotechnology Could Cure Teenage Acne Forever


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Scientists at UC Santa Barbara have created the most high-tech solution to teenage anxiety yet: a treatment for acne that uses a combination of ultrasound, gold-covered nanoparticles, and lasers.

The research is unique because it has created what amounts to a therapeutic regimen that works in three distinct steps. And rather than treating the symptoms of acne, like medications that can dry the face and cause extreme sensitivity to sunlight, the nanotechnology treatment attacks acne at its source.

First, golden nanoparticles, whose width is less than one-hundredth that of a human hair, are applied to the skin. Then, ultrasound pushes the particles through the hair follicle into the sebaceous gland, which releases the oily substance responsible for causing acne. Finally, a laser is shined on the skin that turns the gold particles into heat, disabling the glands

Published in the Journal of Controlled Release, researchers explain that the treatment would not cause the skin to dry out since the blocking of follicles would simply be prevented:

“Called selective photothermolysis, the method does not irritate or dry the skin’s surface. In addition, it poses no risk of resistance or long-term side effects that can occur with antibiotics or other systemic treatments.”

The extremely small size of the golden particles that penetrate hair follicles is the key to the treatment, an advance brought about by the development of nanotechnology, or the ability to control physical elements at the nanoscale. The future for this technology is promising, particularly regarding the treatment of medical conditions located in the brain.

An obstacle called the blood-brain barrier currently prevents most medications from treating the brain directly, but nanotechnology can overcome those obstacles. More interesting still is the technology’s potential to aid learning by carrying encoded information directly to memory centers in the brain. It’s a technology currently beyond the horizon, to be sure, but Nicholas Negroponte explains how it would work in his Big Think interview:

“The best way to interact with the brain is from the inside, from the bloodstream. Because if you inject tiny robots into the bloodstream, they can get very close to all the cells and nerves and things in your brain, really close. So if you want to input information or read information, you do it through the bloodstream. So by extension … you could in theory load Shakespeare into your bloodstream and as the little robots get to the various parts of the brain, they deposit little pieces of Shakespeare or little pieces of French if you want to learn how to speak French.”

MIT Freezes Water At Boiling Point


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This photo shows a glaciologist removing a core of ice to study the chemical make-up of its body dating back to 1840, in Law Dome Camp, Antartica, 1993. The 2016 MIT study in question happened at a nano-scale – so it’ll be a while (or never) before they c

Quick, what temperature does water boil or freeze at? You probably know this like the back of your hand, 100 and 0 degrees Celsius or 212 and 32 Fahrenheit. Well, now we can freeze water above the boiling point. If you feel like your head’s about to explode with that image, don’t worry. We’ll explain.

It is known to anybody who is familiar with the laws of pressure, or who has tried to cook in the mountains, that the boiling and freezing points of water change when the water is exposed to differing pressures. Normally this effect is small, and only has causes differences of a few degrees. Researchers at MIT found that if water is placed inside a tiny enough space, a space only slightly larger than the water molecules themselves, then the freezing point can be raised to above its boiling point. This is done by means of carbon nanotubes, small straw-shaped structures that are the workhorse of nanotech.

The team of researchers published their findings in the journal Nature Nanotechnology, and include Michael Strano, Kumar Agrawal, Steven Shimizu, Lee Drahushuk, and Daniel Kilcoyne among other partners and assistants. Dr. Strano is especially excited by the results, and remarks on how unexpected they are:

The effect is much greater than anyone had anticipated,” he says. The effects were also in an unexpected direction; the researchers had anticipated that the freezing point would go down.

But, what use could this possibly have, other than just being a curiosity? More than you might suppose. Because of the high freezing point, the technology could be used to make ice wires, taking advantage of the extremely high conductivity of water and the stability of the ice at room temperature. Dr. Strano mentioned that application specifically, “This gives us very stable water wires, at room temperature.”  Nanotechnology is a new field, with many possible applications, ranging from computers, to medicine of all kinds, and even to facial care.

There is still a great deal about this process that remains unknown. Chief among them is how the water even gets into the tubes; the researches set the water in place for this experiment, but carbon nanotubes are considered to be water repellent, and the entry of the water in the tubes is difficult to explain logistically. Dr. Strano also notes that the word “ice” is too precise to use to describe the water in the tubes. While it is solid, it may not have the crystalline structure of ice at the molecular level.

What brave new world do we live in, where water can freeze above 100 degrees? One where nanotech is king? Or is nanotech past its prime already? This discovery is new, and further research is needed, but what is certain is that exciting developments await.

Nanotechnology Accelerates Green Energy Production


Nanotechnology is a field that’s receiving a lot of attention at the moment as scientists learn more every day about the benefits it can bring to both the environment and our health. There are various ways in which nanotechnology has proved itself useful including in developing enhanced solar cells and more efficient rechargeable batteries, and in saving raw materials and energy.

When it comes to nanotechnology, even the smallest achievements make huge differences, and on November 23, 2016, future technologies were presented to the international congress as part of the “Next Generation Solar Energy Meets Nanotechnology.” Out of the ten projects, three of them were located in Wurzburg and are explained in a little more detail below:

  • Eco-friendly inks for organic solar cells: Over at the University of Erlangen-Nuremberg, Professors Vladimir Dyakonov and Christoph Brabec have created eco-friendly photovoltaic inks using nanomaterials and have developed a new simulation process at the same time. Dyakonov explains, “They allow us to predict which combinations of solvents and materials are suitable for the eco-friendly production of organic solar cells.”
  • Nanodiamonds for ultra-fast electrical storage: If we want to have powerful, yet highly efficient electric vehicles then we need some way of storing the energy as a standard battery couldn’t handle it. Supercapacitors are great regarding acting as an efficient energy storage system. But, because their energy density is so low they need to be quite large in order to deliver any reasonable amount of energy. However, further work is being done in this area currently, and progress is promising.  Professor Anke Kruger, head of the project, says “Based on these findings, it is now possible to build application-oriented energy stores and test their applicability.”
  • Increased storage capacity of hybrid capacitors: Better energy storage systems were also the focus of Professor Gerhard Sextl and his team’s project. Their hybrid capacitors can store more energy due to the embedded lithium ions and can do it quickly through the use of a supercapacitor. Sextl says, “We have managed to develop a material that combines the advantages of both systems. This has brought us one step closer to implementing a new, fast and reliable storage concept.”

Next Generation Carbon Nanotube Computer Memory is on the Way to Take on Memory Market


Founded back in 2001, and most well known for being pioneers in semiconductors and nanotechnology, Nantero is making the headlines again as they secure $21 million for their next big venture. The nanotech company has set out to develop a new type of computer memory that’s stronger than steel but less dense than aluminum.

In the fifteen years Nantero has been in operation, it’s managed to secure $110 million in funding. With this new round of funding the team at the nanotech company is looking to get their lead product, NRAM (non-volatile random-access memory), out to a host of new customers including Fujitsu Semiconductor and Mie Fujitsu Semiconductor as well as introduce other products into the market too. Much of the new funding came from Globespan Capital Partners, with some anonymous new and existing investors too. Some of the company’s previous investors include Harris & Harris Group, Draper Fisher Jurvetson, and CRV.

This new type of technology is all set to replace flash memory and dynamic random-access memory (DRAM). It’s got better storage capabilities and better density and speed than anything that’s currently on the market, and sales are expected to take off quite quickly. The chips have much better thermal and electrical conductivity properties than any other material as are made using carbon nanotubes. Greg Schmergel, co-founder and CEO of Nantero said, “With this additional funding, we will be able to help these existing customers speed their time to market while also supporting the many other companies that have approached us about using Nantero NRAM in their next generation products.”

Revolutionizing the World with Genetic Material Computers


A new nanostructure has been created by researchers for conducting electricity using DNA and gold plating. The new nanostructure has the potential to be used for future electronics after improvements. These DNA origami nanostructures are fascinating. Using DNA as construction material capable of holding scar folds of molecules and atoms has been a huge step for modern nanostructures.

Scientists from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Paderborn University recently developed gold-platted nanowires. As published in the journal Langmuir, the gold plated nanowires independently assemble themselves from single DNA strings.

Artur Erbe from the institute of Icon Beam Physics and Material Research explained that nanowires are able to conduct electricity because of their gold-platting. Two electrical contacts connected the Nano-sized structures. What is even more intriguing is the use of modified DNA strings. These were used as stable double strands combined through their base pairs. Thus, they allowed structures to independently take any desired form. Therefore, complex structures were developed.

Credits: B. Teschome, A. Erbe, et al.
According to Erbe, using this approach (which resembles Japanese paper folding technic origami hence the name DNA-origami) will allow the creation of tiny patterns. The ‘top down’ method i.e. developing Nano sockets using base material that is chiseled until desired structure is formed. The new ‘bottom up’ method is set to change the usual method of making these electric components.

However, there is a stumbling block. Erbe pointed out that “Genetic matter doesn’t conduct a current particularly well.” Furthermore, conductive materials need better melding. Not to mention the use of cheaper standard wire coating and not gold. Overall, this is a promising research. If successful, this Nanowire technology could become the future of electronics.

Researchers “Grow” Nanoparticles Using Gold and Light


IN BRIEF

Florida chemists have found a way to use gold in the synthesis of nanoparticles, opening the path for their use in biotech applications.

ALTERNATE MATERIALS

Many are heralding the coming age of nanoparticles and nanotechnology. A new development may change how we make these wonder particles.
A team from the University of Florida has found a way to use gold in crystals grown by light to create nanoparticles, widening the path for nanoparticle use in biotechnology.
University of Florida
One way of making nanoparticles is through palsmon-driven synthesis: being “grown” in crystal formations with special use of light. However, silver is needed to control this process. That limits use in biotechnology. “How does light actually play a role in the synthesis? [This knowledge] was not well developed,” said David Wei, an associate professor of chemistry who led the research team. “Gold was the model system to demonstrate this.” Gold is far more desirable than silver due to its malleability, non-reaction with oxygen, and conductivity. Therefore, this makes for better nanoparticles, especially when the particles are intended for use in the human body.

GOLDEN OPPORTUNITIES

Polyvinylpyrrolidone, or PVP is the substance which enables the use of gold. This is a substance commonly found in pharmaceutical tablets. When used in the plasmon-driven synthesis, the substance allows scientists to better control the growth of crystals.
The research, published in Nature Materials, has shown that PVP has the potential to relay light-generated “hot” electrons to a gold surface to grow the crystals. This is the first research to show the use of plasmonic synthesis to make high-yield gold nanoprisms. Even more, the team showed the use of visible-range and low-power light as the light source in conducting the experiment.
This, coupled with nanoparticles being used in solar photovoltaic devices, now allows the possibility of harnessing solar energy for chemical synthesis, to make nanomaterials, or for other general applications in chemistry.

Revolutionary Injectable Nanoparticles Can Help Stop Internal Bleeding


IN BRIEF

Researchers have developed injectable nanoparticles that speed up the blood clotting process anywhere in the body. If the research pans out, the silent-killing trauma of patients from blood loss could be prevented.

In dire situations, stopping excessive bleeding could mean the difference between life and death. Although there are many existing methods for controlling external bleeding, only surgery can halt internal blood loss.

New research from the University of Maryland, Baltimore County (UMBC) could change the way we deal with this situation.

Nanoparticles (green) help form clots in an injured liver. Credit: Erin Lavik, Ph.D.
Nanoparticles (green) help form clots in an injured liver. 

The UMBC researchers aim to reduce patients’ trauma resulting from blood loss by using injectable nanoparticles that speed up the blood clotting process, either internally or externally.

The process involves the addition of a molecule (to the nanoparticles) capable of sticking to a glycoprotein found only on activated platelets. Then, the nanoparticles will bind to the activated platelets—acting as a bridge—helping the glycoprotein and platelets join together to form clots.

After achieving a 50% reduction in bleeding time for rodents, Lavik’s team tested the method on pig’s blood. The researchers were forced to tweak their nanoparticle storage solution, adding a slippery polymer to keep the nanoparticles from sticking to each other, after the method triggered an immune response.

The next challenge: human blood, and additional research to be sure any unwanted clotting doesn’t occur. Still, a future where we can quickly stop internal bleeding, doesn’t seem too far off.

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