Archive for year: 2017

Nanoparticle generation is notorious for being a clumsy, awkward process that can take months to perfect. This means that research which involves multiple different types of nanoparticles is often held back by the creation of the nanoparticles themselves. To address this problem, VSPARTICLE have developed a new instrument that uses spark ablation to produce particular nanoparticles, of a set size distribution, all in one afternoon.

What are the conventional problems associated with the creation of nanoparticles? How does the VSP-G1 nanoparticle generator avoid these?

The problems faced in nanoparticle production are threefold. The process is time-consuming and it is not interchangeable for different materials, meaning a new method must be used to generate different nanoparticles and, in addition to this, reproducibility is also a big issue.

Because of this, researchers spend years of their Ph.D. on the synthesis of nanoparticles, instead of on the actual application of them. Conventional methods rely on carefully tweaked chemistries, which makes it difficult to tune the size, composition or scale of a synthesis.

Another problem is post-processing – conventional methods provide a powder or suspension as an end product. This is problematic as powders need to be re-dispersed before use, whilst suspensions require the surfactants and solvents to be removed. Both are costly procedures and often involve the risk of worker exposure.

VSPARTICLE aims to provide a complete solution from nanoparticle synthesis to the immobilization of nanoparticles on or into your product. The VSP-G1’s settings can be adjusted without effort, making changes in nanoparticle size and composition trivial and helping in scaling up.

The method used in the VSP-G1 (spark ablation) is easy, fast and reproducible. Because spark ablation is a purely physical process, the fabrication of particles and the integration of them into your device always works in exactly the same way, enabling you to start working on your product without the hassle that comes with conventional production.

A pie chart demonstrating the wide range of application areas of nanoparticles. An interactive copy can be found here.

What materials can the VSP-G1 nanoparticle generator create nanoparticles from?

The VSP-G1 can create nanoparticles from any (semi-)conducting material, allowing researchers to create nanoparticles from 90% of the elements in the periodic table. Furthermore, materials that are normally immiscible on the macroscale can be alloyed on the nanoscale using spark ablation technology. An example of this are Au-Cu particles, created using sparks between an Au and a Cu electrode.

The particles are created in a continuous flow of gas, typically argon or nitrogen. The gas can easily be delivered through post-processing stages, which facilitates size-selection, or modifications such as oxidations.

As particles become larger, they nucleate and form solid particles. The morphology and primary size that is favored during nucleation can easily be tweaked using the VSP-G1.  Depending on your substrate, VSPARTICLE can also provide different solutions to immobilize the produced particles.

How precise is the nanoparticle creation process?

In terms of stability, the standard deviation of the particle size output can be reduced to less than two percent. Particles produced by the spark have a primary particle size, which can be tuned by altering the annealing temperature. Particle size distributions typically have a geometric standard deviation of 1.3-1.4 nm. For specific applications, size distributions of +/- 0.2 nm or better can be achieved.

The VSP-G1 is most precise in the 0-20 nm range. However, with additional equipment, particles can be selected on their size, accurately down to 0.1 nm.

In which fields do you see the VSP-G1 nanoparticle generator making the biggest impact?

There are four fields in which we see a great future for the VSP-G1: microelectronics, catalysis, energy and healthcare.

Compared to printing electronics with conductive inks, using beams of pure nanoparticles to print conductive lines allows for sintering at lower temperatures. The outcome of this is the creation of conducting lines which possess a higher conductivity.

‘Printing’ with a nanoparticle spray can also be achieved for the coating of an entire surface, to produce a porous later that could be used for sending – the porosity of laters produced by the VSP-G1 makes it possible to detect even the lowest amount of gas or biomolecules.

The use of nanoparticles in catalysis is already established, but a reliable method of creating nanoparticle catalysts for size and composition comparisons is not. Differing metal and metal-oxide nanoparticles of various shapes can be easily compared against one another using the VSP-G1 allowing the optimal nanoparticle properties for a particulr catalytic process to be determined. Using the new VSPARTICLE accessory particles can be directly deposited onto an in-situ TEM grid for analysis.

Because nanoparticles have strong applications in the fields of electronics and catalysis it is inevitable that they will influence the production and storage of energy as well.  Nanoparticles are currently being used to improve solar cells absorption of sunlight. A higher absorption of solar enables a higher energy production, during sunny days, nanoparticles enable nano-structured super capacitors to store more energy.

In the healthcare field, scientists working on nanoparticle therapies, such as iron oxide nanoparticles for hyperthermia and enhanced MRI, antibacterial nanosilver or gold nanoparticles for targeted drug delivery are struggling to get FDA approval. This is mostly due to the presence of chemical contaminants in their nanoparticle formulations. By using spark ablation, researchers can produce nanoparticles which are contaminant free, speeding up the approval process and working faster to nanomedicine end-user applications.

Shutterstock |  Andrey VP

What advantages do your nanoparticles provide for the Semiconductor and other patterning industries?

The extremely small size of nanoparticles makes them very sensitive to external stimuli. This sensitivity can be used to develop novel sensors or used as a way to create metallic interconnects using low-temperature processes.

Nanoparticle generators make it possible for a semiconductor manufacturer to have full control over their entire production chain – from nanoparticle generation to the integration of the nanoparticles in the devices they create.

What inspired the team at VSPARTICLE to develop the VSP-G1? Why did you choose to use Spark Ablation?

While we were at the Delft University of Technology, we noticed many people had difficulties in adapting nanoparticle recipes for their need. These were researchers in a multidisciplinary environment, with expertise in fields such as materials for energy conversion and storage, photovoltaics, healthcare and catalysis. We saw researchers spend months to obtain the nanoparticles they required before they could carry on with their research.

In contrast, students in our lab would receive 2-hours of training, and would have nanoparticles of the composition and size they wanted by the end of the day. This is largely due to the flexibility of spark ablation: if we can make the bulk electrode, we can make the nanoparticles. We want to give other people the same possibilities.

Can VSPARTICLE help their customers develop their own nanoparticle production processes tailored to their application?

Using VSPARTICLE spark generators, the need to change the particle production process is taken away. VSPARTICLE means researchers don’t have to worry about particle production and lets them focus on their true application from day one.

By considering the whole process, from nanoparticle production to application and bringing solutions in deposition/integration, VSPARTICLE can speed up research and facilitate industrialization.

1. Turmeric

The herb turmeric has a therapeutic effect on coughs, particularly a dry cough.

• Heat half a cup of water in a boiling pot. Add one teaspoon turmeric powder, and one teaspoon black pepper. You may also add cinnamon sticks. Boil this for about two to three minutes. Add one tablespoon of honey. Drink this daily until the condition improves.
• Alternatively, make an herbal tea by adding one teaspoon of turmeric powder and one teaspoon of carom seeds to a cup of water, and boil it until water reduces to one-half cup. Add some honey and drink this herbal solution two to three times a day.
• Another way to use turmeric is to roast turmeric root and grind it into a smooth powder. Mix it with water and honey, and drink it twice a day.

2. Ginger

Ginger is one of the most popular natural cures for a cough.

• Cut fresh ginger into small slices and crush them slightly. Put them in a cup of water and bring to a boil. Drink this herbal solution three to four times a day for relief from sore throat, non-stop coughing and even congestion. You can also some lemon juice and honey to it.
• Another option is to chew fresh raw ginger on and off throughout the day to reduce your cough.

3. Lemon

Lemons can be used in a variety of ways for curing coughs. Lemons have properties that reduce inflammation and also provide a dose of infection-fighting vitamin C.

• A simple cough syrup can be made by combining two tablespoons of lemon juice and one tablespoon of honey. Drink this healthy syrup several times a day.
• Another way to use lemons is to blend lemon juice with a little honey and a pinch of cayenne pepper and then drink it.

4. Garlic

Garlic has both antibacterial and antimicrobial components that help treat coughs.

• Boil two to three cloves of garlic in a cup of water and add a teaspoon of oregano. Allow it to cool to room temperature, add some honey and drink it. This will help your breathing and alleviate other cough symptoms.
• Eat a clove of crushed garlic mixed with a few drops of clove oil and some honey for sore throat relief. You can also use garlic in your cooking.

5. Onion

One of the simplest home remedies for a cough is to cut onions. Breathing in the strong vapors can help stop coughing.

• You can also make a cough syrup from baked onion juice, comfrey tea and honey. Drink it daily to get relief from a dry cough.
• Another option is to combine one-half teaspoon of onion juice with one teaspoon of pure honey. Swallow this solution at least twice a day to alleviate a cough and soothe your throat.

6. Hot Milk with Honey

Hot milk with honey can relieve a dry cough and reduce chest pain you may be experiencing from continuous coughing. For best results, drink it before going to sleep. For added benefits from the analgesic properties of honey, swallow a teaspoon of plain honey on empty stomach. This will help clear the mucus and soothe your throat.

Researchers have designed a graphene-based tattoo that can be directly laminated onto the skin with water, similar to a temporary tattoo. But instead of featuring artistic or colorful designs, the new tattoo is nearly transparent.

The graphene tattoos retain their full function for about two days, but can be peeled off by a piece of adhesive tape if desired. (Credit: Shideh Kabiri Ameri et al. 2017 American Chemical Society)

Its main attraction is that graphene’s unique electronic properties enable the tattoo to function as a wearable electronic device, with potential applications including biometric uses (such as measuring the electrical activity of the heart, brain, and muscles), as well as human-machine interactions.

The researchers, led by Deji Akinwande and Nanshu Lu at the University of Texas at Austin, have published a paper on the new graphene electronic tattoo in a recent issue of ACS Nano.

In some ways, the graphene electronic tattoo is similar to commercially available electronic devices for health and fitness tracking: both kinds of devices are capable of heart rate monitoring and bioimpedence (a measure of the body’s response to an electric current). But because the ultrathin graphene tattoos can fully conform to the skin, they offer medical-grade data quality, in contrast with the lower performance of the rigid electrode sensors mounted on bands and strapped to the wrist or chest. Due to the high-quality sensing, the researchers expect that the graphene tattoos may offer promising replacements for existing medical sensors, which are typically taped to the skin and require gel or paste to enable the electrodes to function.

“The graphene tattoo is a dry physiological sensor which, because of its thinness, forms an ultra-conformal contact to skin, resulting in increased signal fidelity,” coauthor Shideh Kabiri Ameri at the University of Texas at Austin told Phys.org. “Conformability results in less susceptibility to motion artifacts, which is one the biggest drawbacks of conventional dry sensors and electrodes for physiological measurements.”

The new tattoos are made of graphene that is coated with an ultrathin backing layer of transparent polymer poly(methyl methacrylate) (PMMA). During fabrication, the graphene/PMMA bilayer is transferred to a piece of ordinary tattoo paper, and the bilayer is then carved into different patterns of serpentine ribbons to make different types of sensors. The finished tattoo is then transferred to any part of the body by bringing the graphene side in contact with the skin and applying water to the back of the tattoo paper to release the tattoo. The tattoos retain their full function for around two days or more, but can be peeled off by a piece of adhesive tape if desired.

Since the researchers previously showed that, theoretically, a graphene tattoo must be less than 510 nm thick to fully conform to human skin and exhibit optimal performance, the tattoo they fabricated here is just 460 nm thick. Combined with graphene/PMMA bilayer optical transparency of approximately 85%, and the fact that the tattoos are more stretchable than human skin, the resulting graphene tattoos are barely perceptible, both mechanically and optically.

Tests showed that the graphene electronic tattoos can be successfully used to measure a variety of electrophysiological signals, including skin temperature and skin hydration, and can function as an electrocardiogram (ECG), electromyogram (EMG), and electroencephalogram (EEG) for measuring the electrical activity of the heart, muscles, and brain, respectively.

“Graphene electronic tattoos are most promising for potential applications in mobile health care, assisted technologies, and human machine interfaces,” Kabiri Ameri said. “In the area of human machine interfaces, electrophysiological signals recorded from the brain and muscles can be classified and assigned for specific action in a machine. This area of research can have applications for the internet of things, smart houses and cities, human computer interaction, smart wheelchairs, speech assistance technology, monitoring of distracted driving, and human-robot control. Recently we have demonstrated the application of graphene tattoos for sensing human signals to wirelessly control flying objects. That demonstration will be reported in the near future.”

The existence of human pheromones remains controversial. It’s clear that many plants and animals species use hormonal secretions to communicate information relating to reproduction. For example, in 1959 researchers discovered that female silkworms secreted a powerful aphrodisiac, called bombykol, that can attract male silkworms from miles away. To date, however, ironclad evidence that human behavior is governed by pheromones remains elusive.

Nevertheless, there are a number of intriguing studies, which suggest the surprising ways that scents, secretions and body odors containing pheromones may influence human behavior unconsciously.

Unconscious communicationAccording to Bettina Pause, a psychologist, “We’ve just started to understand that there is communication below the level of consciousness. My guess is that a lot of our communication is influenced by chemosignals.”

In mammals, for instance, pheromones are detected by a structure in the nose called the vomeronasal organ, which relays signals to the hypothalamus a region of the brain that controls emotional states, hormonal regulation and sexual arousal.

Some of the most important evidence for the existence of human pheromones comes from a 1998 study by Dr. Martha McClintock, who found that women who live in close proximity (the same dorm, for example) tend to have synchronized menstrual cycles. Scientists believe that chemical messages in sweat are responsible for this harmonization of periods.

Pheromones and brain imagingResearchers have found that certain smells activate the part of the brain related to sexuality.

One powerful form of evidence that pheromones exist comes from PET scanning technology, which can examine the effect of chemical odors on male and female brains. In one study, researchers found that certain hormone-like smells activated specific areas in the hypothalamus related to sexuality, which are not triggered by other odors.

In the words of Dr. David Berliner, “These findings corroborate that human pheromones do exist, and that women can communicate chemically with men and vice versa. This is a very important finding because it shows specific areas of the brain that are activated by these chemicals.”

As you might expect, the brains of heterosexual men and women respond very differently to specific chemical messengers. For example, the brain regions in the female hypothalamus are highly active when women are exposed to testosterone-like chemicals (while exposure to estrogen-like messengers has no effect). Conversely, the brain areas in the male hypothalami light up like a Christmas tree when men are exposed to estrogen-like hormones.

Scientists believe this gender-specific response to chemical secretions shapes the way men and women to perceive each other on an unconscious level.

Can pheromones make you more attractive?

If pheromones govern sexual arousal, then can they be harnessed to make people more attractive? More specifically, could pheromones be added to perfumes, which could be used to lure desired mates?

One study from the University of Chicago found that pheromone-type chemical can heighten the heart rate, increase body temperature and change mood. As of yet, however, scientists have been unable to isolate the specific chemicals that trigger attraction and sexual desire.

Of course, many perfume manufacturers claim that their fragrances can spark desire. In fact, most of these products contain pheromones from animals. However, most scientists insist that pheromones are species specific. In other words, until researchers can isolate specific human pheromones or develop synthetic analogs, then a true love potion of love will remain elusive.

Nevertheless, scientists are continuing to investigate pheromones for their scientific, commercial and therapeutic potential. For example, a company called Pherin Pharmaceuticals is looking into ways to use pheromones messengers to alleviate stress, anxiety and menstrual cramps.

How pheromones may influence human behavior

• The odors breastfeeding women emit from their nipples attracts infants and primes women without children to be more sexually aroused.
• A compound derived from testosterone (called androstadienone) has been shown to make women feel more relaxed.
• Scientists are investigating something called the histocompatibility complex. This refers to a genetically-based “odor print,” which involves scents that reflect certain characteristics found in the genes and the immune system.
• According to the olfactory neuroscientist Charles Wysocki, “With the exception of identical twins, no two individuals are likely to have the same odor print.”

Research by Wysocki and others indicates that women prefer the musky scent of men who happen to have gene characteristics that match up well with their own DNA. In other words, the nose knows. That is, odor prints may be a huge driver of attractiveness in so far as they help people pick mates with DNA that complements their own. This unconscious form of selection benefits offspring.

Love is in the air

Scientists are still a long way off from unraveling the mysteries of attraction and the role that pheromones may play in influencing sexual behavior. For centuries, people have used expressions like “love is in the air” and “love is a matter of chemistry.” The emerging science of pheromones suggests that these proverbial adages may be far truer than anyone imagined.