Autor: Liliana Decu

Nanopowder eliberează puterea în urină (w / video)(Nanopowder releases power in urine (w/video))

Ceea ce facem ca oamenii de stiinta ai Armatei este dezvoltarea de materiale si tehnologii care vor aduce beneficii direct Soldierului si imbunatati capacitatile lor”, a spus dr. Kristopher Darling, cercetator ARL. „Am dezvoltat o nouă tehnică de procesare pentru a sintetiza un material care sparge în mod spontan apa în hidrogen”.Echipa de cercetare a anunțat, în vara aceasta, că o pulbere nano-galvanică pe bază de aluminiu pe care o dezvoltau producea hidrogen pur atunci când vine în contact cu apa. Cercetătorii au observat o reacție similară atunci când adăugă pulberea lor în orice lichid care conține apă.

Posted: Sep 12, 2017

Nanopowder releases power in urine (w/video)

(Nanowerk News) Scientists at the U.S. Army Research Laboratory observed an unexpected result when combining urine with a newly engineered nano-powder based on aluminum. It instantly releases hydrogen from the urine at much higher rate than with ordinary water.
The research team announced earlier this summer that a nano-galvanic aluminum-based powder they were developing produced pure hydrogen when coming into contact with water. The researchers observed a similar reaction when adding their powder to any liquid containing water.
„What we do as Army scientists is develop materials and technology that will directly benefit the Soldier and enhance their capabilities,” said Dr. Kristopher Darling, an ARL researcher. „We developed a new processing technique to synthesize a material, which spontaneously splits water into hydrogen.”
Hydrogen, the most plentiful element in the universe, has the potential to power fuel cells and provide energy to future Soldiers.
Fuel cells generate electricity quietly, efficiently and without pollution. According to a Department of Energy’s website, fuel cells are „more energy-efficient than combustion engines and the hydrogen used to power them can come from a variety of sources.”
„We have calculated that one kilogram of aluminum powder can produce 220 kilowatts of energy in just three minutes,” said Dr. Anit Giri, also an ARL researcher.
In space, astronauts recycle waste water and urine because drinking water is a precious commodity. For Soldiers in austere environments, there are many precious commodities. Power and energy is becoming increasingly important to run communications and electronics gear for away teams, which can’t be resupplied.
Making use of urine as fuel source may result in tremendous benefits for Soldiers, officials said.
„When we demonstrated it with urine, we saw almost a factor of twofold increase in the reaction rates,” Darling said. „We were very excited. As a group we have been pushing for the last few months on developing the efficiency and the reaction kinetics to try to get them faster.”
The team is still investigating why urine causes a faster reaction, but it may have something to do with the electrolytes and the acidity of the liquid.
„It’s unique because the rate of the reaction is so efficient and extremely rapid from such a small volume of material,” Darling said.
The team is working closely with other researchers at the laboratory, including the Sensors and Electron Devices Directorate, to discover how to harness the material as a potential energy source.
„It was a spontaneous finding,” Darling said. „We weren’t expecting to develop this material specifically for hydrogen production. It was a group effort. We came together as a team to understand the importance of the discovery. This has great potential for benefiting Soldiers.”
In a statement, Dr. Philip Perconti, the laboratory director, said it „may find great utility for forward deployed troops who need a compact and lightweight energy source.”
In the coming months, the team will continue to investigate and push the limits of the discovery, to try and understand its implications.
„Our basic focus is materials development and optimization,” Darling said. „We’re looking at how we can optimize the composition, its interactions with other fluids, including saliva and other liquids available to Soldiers in a field environment.”
Source: U.S. Army Research Laboratory

 

Digitizatoarele cu infraroșu cu putere zero, bazate pe microprocesoare micromecanice îmbunătățite cu plasmă(Zero-power infrared digitizers based on plasmonically enhanced micromechanical photoswitches)

Senzorii de ultimă oră folosesc electronica activă pentru a detecta și a discrimina vibrațiile, vibrațiile sonore și alte semnale

Infrared-analytical pag 35-47

Nanosenzorul senzitiv se trezește numai în prezența unui semnal de interes (Dormant nanosensor awakens only in the presence of a signal of interest )

Construiți un senzor minuscul care detectează o semnătură de lungimi de undă în infraroșu (IR) caracteristice unei conducte de esapament fierbinți, unui foc de lemn sau chiar unei ființe umane. Proiectați senzorul astfel încât acesta să rămână în stare latentă și nesupravegheată, dar întotdeauna în stare de alertă, chiar și ani de zile, fără a atrage energia bateriei. Și construiți senzorul astfel încât actul de detecție în sine poate iniția emiterea unui semnal care avertizează războinicii, pompierii sau alții că a fost detectat un „semnal de interes”. Este doar o tehnologie de inteligență, recunoaștere și supraveghere (ISR), care poate spori gradul de conștientizare a situației, reducând în același timp necesitatea unor misiuni de întreținere potențial periculoase pentru înlocuirea bateriilor de descărcare. „Ceea ce este cu adevărat interesant în ceea ce privește tehnologia Northeastern IR sensor este că, spre deosebire de senzorii convenționali, acesta consumă zero putere de stand-by atunci când lungimile de undă IR care trebuie detectate nu sunt prezente”, a declarat Troy Olsson, manager al programului N-ZERO în DARPA’s Microsystems Technology Office. „Când aceste lungimi de undă IR sunt prezente și afectează senzorul IR al echipei Northeastern, energia din sursa IR încălzește elementele senzoriale care, la rândul lor, determină mișcarea fizică a componentelor senzorilor cheie. Aceste mișcări au ca rezultat închiderea mecanică a elementelor de circuit deschis, în alt mod, ceea ce duce la semnalele de detectare a semnăturii IR. „

Posted: Sep 12, 2017

Dormant nanosensor awakens only in the presence of a signal of interest

(Nanowerk News) Here’s your task. Build a tiny sensor that detects a signature of infrared (IR) wavelengths characteristic of a hot tailpipe, a wood fire, or perhaps even a human being. Design the sensor so that it can remain dormant and unattended but always alert, even for years, without drawing on battery power. And build the sensor so that the act of detection itself can initiate the emission of a signal that alerts warfighters, firefighters, or others that a “signal-of-interest” has been detected. It’s just the sort of intelligence, reconnaissance, and surveillance (ISR) technology that can increase situational awareness while minimizing the need for potentially dangerous maintenance missions to replace run-down batteries.
Reporting in the journal Nature Nanotechnology („Zero Power Infrared Digitizers Based on Plasmonically-enhanced Micromechanical Photoswitches”), a research team at Northeastern University, led by Electrical and Computer Engineering Associate Professor Matteo Rinaldi, reports pulling off this tall order of DARPA’s Near Zero Power RF and Sensor Operation (N-ZERO) program with a device the Boston team refers to as a “plasmonically-enhanced micromechanical photoswitch.”
micro features of multiple, wavelength-specific sensor patches
The micrograph features the multiple, wavelength-specific sensor patches that enable this N-ZERO device to capture infrared signatures of specific heat-emitting sources. (Image: DARPA)
“What is really interesting about the Northeastern IR sensor technology is that, unlike conventional sensors, it consumes zero stand-by power when the IR wavelengths to be detected are not present,” said Troy Olsson, manager of the N-ZERO Program in DARPA’s Microsystems Technology Office. “When those IR wavelengths are present and impinge on the Northeastern team’s IR sensor, the energy from the IR source heats the sensing elements which, in turn, causes physical movement of key sensor components. These motions result in the mechanical closing of otherwise open circuit elements, thereby leading to signals that the target IR signature has been detected.”
The sensor is a showcase of clever physics and engineering, including a grid of nanoscale patches whose specific dimensions limit them to absorb only particular IR wavelengths. “The charge-based excitations, called plasmons (that can be thought of somewhat like ripples on the surface of water), are highly localized below the nanoscale patches and effectively trap specific wavelengths of light into the ultra-thin structure, inducing a relatively large and swift spike in its temperature,” Rinaldi explained. These temperature spikes, in turn, lead to an upstream sequence of events that culminates in circuit-completing deformations of other parts of the sensor.
“The technology features multiple sensing elements—each tuned to absorb a specific IR wavelength,” Olsson noted. “Together, these combine into complex logic circuits capable of analyzing IR spectrums, which opens the way for these sensors to not only detect IR energy in the environment but to specify if that energy derives from a fire, vehicle, person or some other IR source.”
Consider the identification of vehicles from their IR emissions. Engines that burn gasoline or diesel fuels emit specific compounds in their exhaust gases. Among these compounds are CO2, CO, H2O, various oxides of nitrogen and sulfur (NOx and SOx, respectively), and hydrocarbons such as methane. “As a result, the infrared emission spectra of the heated tailpipe gases coming out of vehicles such as trucks, cars or aircraft can by themselves act as a signature specific to a vehicle type,” explained Zhenyun Qian, who has been working with Rinaldi and other research team members on the N-ZERO program.
A primary goal of the N-ZERO program is to develop fundamental technologies that open the way to new and more capable sensor systems relevant to national security. The NU team points out in its Nature Nanotechnology paper that the same technology could become important over the coming years as the Internet of Things expands to include hundreds of billions of devices, ranging from cars, to appliances, to remotely deployed sensors. “The capability of consuming power only when useful information is present will result in nearly unlimited duration of operation for unattended sensors deployed to detect infrequent but time-critical events, with a groundbreaking impact on the proliferation of the Internet of Things,” the Northeastern researchers predict in their paper.
Source: DARPA

Read more: Dormant nanosensor awakens only in the presence of a signal of interest

Extinderea limitelor conductorilor elastici(Stretching the limits of elastic conductors)

Noul material, produs sub formă de cerneală ca o pastă, pot fi imprimate în diferite modele pe textile și suprafețe de cauciuc ca cabluri alungibil pentru dispozitivele purtabile care încorporează senzori, precum și a da funcții ale pielii cum ar fi umane exterioare robotului ( Nature Materials , „Printable conductori elastici prin formarea in situ a nanoparticulelor de argint din fulgi de argint ” ).

Posted: Sep 12, 2017

Stretching the limits of elastic conductors

(Nanowerk News) A newly developed printable elastic conductor retains high conductivity even when stretched to as much as five times its original length, says a Japanese team of scientists. The new material, produced in paste-like ink form, can be printed in various patterns on textiles and rubber surfaces as stretchable wiring for wearable devices incorporating sensors, as well as give human skin-like functions to robot exteriors (Nature Materials, „Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes”).
LED-integrated pressure-sensing glove
LED-integrated pressure-sensing glove. Each fingertip pressure sensor mounted on this glove is connected to an LED. The intensity of the LEDs varies according to the pressure applied by the fingertips. The glove makes it possible to ascertain degrees of pressure that are difficult to obtain just by examining images. (Image: Someya Group, The University of Tokyo)
The development of wearable devices such as those monitoring a person’s health or physical performance, like heart rate or muscle activity, is currently underway with some products already on the market. Moreover, with the advent of robots in areas such as health care and retail, in addition to manufacturing, future applications for sensitive elastic conductive material that can withstand high strain from stretching are likely to increase at a fever pitch.
„We saw the growing demand for wearable devices and robots,” says Professor Takao Someya at the University of Tokyo’s Graduate School of Engineering, who supervised the current study. „We felt it was very important to create printable elastic conductors to help meet the need and realize the development of the products,” he adds.
To achieve a high degree of stretchability and conductivity, the researchers mixed four components to create their elastic conductor. They found that their conductive paste consisting of micrometer-sized silver (Ag) flakes, fluorine rubber, fluorine surfactant—commonly known as a substance that reduces surface tension in liquid—and organic solvent to dissolve the fluorine rubber markedly outperformed the elastic conductor they had previously developed in 2015.
Without stretching, printed traces of the new conductor recorded 4,972 siemens per centimeter (S/cm), high conductivity using the common measure for assessing electrical conductance. When stretched by 200 percent, or to three times its original length, conductivity measured 1,070 S/cm, which is nearly six times the value of the previous conductor (192 S/cm). Even when stretched by 400 percent, or to five times its original length, the new conductor retained high conductivity of 935 S/cm, the highest level recorded for this amount of stretching.
Magnification by a scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the high performance of the conductor was due to the self-formation of silver (Ag) nanoparticles—one-thousandth the size of the Ag flakes and dispersed uniformly between the flakes in the fluorine rubber—after the conductive composite paste was printed and heated. „We did not expect the formation of Ag nanoparticles,” comments Someya on their surprising discovery.
Furthermore, the scientists found that by adjusting variables like the molecular weight of the fluorine rubber, they could control the distribution and population of nanoparticles, while the presence of surfactant and heating accelerated their formation and influenced their size.
To demonstrate the feasibility of the conductors, the scientists fabricated fully printed stretchable pressure and temperature sensors – that can sense weak force and measure heat close to body and room temperatures – wired with the printable elastic conductors on textiles. The sensors, which can be installed easily by laminating onto surfaces by hot pressing with heat and pressure, took precise measurements even when stretched by 250 percent. This is enough to accommodate high-stress flexible areas such as elbows and knees on conformable, form-fitting sportswear or joints on robotic arms often designed to surpass human capabilities and thus undergo higher strain.
The new material, which is durable and suitable for high-capacity printing methods like stencil or screen printing that can cover large surface areas, points to easy installation, and its properties of forming Ag nanoparticles (which are a fraction of the cost of Ag flakes) when printed provide an economical alternative for realizing a wide range of applications for wearables, robotics, and deformable electronic devices. The team is now exploring substitutes for Ag flakes to further reduce costs, while they are also looking at other polymers, like nonfluorine rubbers, and various combinations of materials and processes to fabricate elastic conductors with similar high performance.
Source: University of Tokyo

Read more: Stretching the limits of elastic conductors

Închis, totuși AvertSensor porneste întotdeauna numai în prezența unui semnal de interes(Dormant, Yet Always-AlertSensor Awakes Only in the Presence of a Signal of Interest)

Folosind puterea de stand-by virtuală zero, senzorii ar putea îmbunătăți gradul de conștientizare pentru războinici, adăugați inteligența la Internet a Lucrurilor.Construiți un senzor minuscul care detectează o semnătură a lungimilor de undă în infraroșu (IR) caracteristice unui canal de evacuare fierbinte, unui foc de lemn sau poate chiar unei ființe umane

Dormant

Lasere integrate pe diferite suprafețe (Integrated lasers on different surfaces)

Legarea a fost apoi finalizată la temperaturi relativ scăzute de aproximativ 220 grade Celsius, permițând stratului ultrasonic de oxid de siliciu să efectueze căldură între straturi, reducând potențialul de deteriorare a materialelor, întărind legătura și evitând nevoia de produse chimice periculoase, cum ar fi Piranha soluție și acid fluorhidric, utilizat în legătură directă.
Lucrarea demonstrează un laser versatil pe chip care poate fi integrat pe orice platformă materială și ar putea conduce la noi aplicații pentru dispozitive fotonice, cum ar fi tehnologiile detectorului pe cip și modulatorul pe cip.
„Abordarea la intervale de joasă temperatură este mai simplă și mult mai sigură decât legătura directă și înseamnă că producătorii de laser nu sunt restricționați prin alegerea substratului”, spune Ng.

Posted: Sep 08, 2017

Integrated lasers on different surfaces

(Nanowerk News) Fabricating hybrid semiconductor lasers on materials other than the commonly used silicon-on-insulator (SOI) substrates has proved challenging. Now, A*STAR researchers have developed an innovative technique that can integrate the lasers on to a range of different materials (IEEE Journal of Selected Topics in Quantum Electronics, „Generic heterogeneously integrated III–V lasers-on-chip with metal-coated etched-mirror”).
Schematic of a hybrid laser
Schematic of the hybrid laser. (Image: A*STAR Data Storage Institute)
Hybrid lasers combine the light-emitting properties of group III-V semiconductors like gallium arsenide and indium phosphide, with conventional silicon technologies, offering inexpensive photonic and microelectronic devices for application in optical telecommunication systems.
Their range of applications, however, is limited by the poor light-emitting characteristics of the silicon-on-insulator (SOI) wafers mostly used as substrates in the fabrication process. This spurred Doris Keh-Ting Ng and colleagues from the A*STAR Data Storage Institute to develop an innovative technique for bonding III-V lasers on to other substrates, be it silicon, quartz, or metal alloys.
By using an ultrathin layer of silicon oxide to bond the lasers to a silicon substrate, the researchers developed a simpler, safer and more flexible technique than direct bonding, which relies on chemical bonding between the surfaces.
“The challenge is to produce a smooth, extremely thin layer of silicon oxide on the surface of the substrate,” explains Ng. “By growing the film on the silicon substrate, but not on the III-V substrate, we greatly reduced the complexity of the process and improved the strength of the bond between the two materials.”
After first cleaning the surfaces with an organic solvent, the researchers exposed the surface to an oxygen plasma to increase its adhesive properties. They then initiated the bonding process at ambient temperature by bringing the two substrates slowly together, to reduce the air trapped between them, ensuring a much stronger bond.
The bonding was then completed at relatively low temperatures of around 220 degrees Celsius, allowing the ultrathin layer of silicon oxide to conduct heat between the layers, reducing potential damage to the materials, strengthening the bond and avoiding the need for hazardous chemicals, such as Piranha solution and hydrofluoric acid, used in direct bonding.
The work demonstrates a versatile on-chip laser that can be integrated on to any material platform and could lead to new applications for photonic devices, such as detector-on-chip and modulator-on-chip technologies.
“The low temperature interlayer approach is simpler and much safer than direct bonding, and means that laser manufacturers are not restricted by the choice of substrate,” says Ng.
Source: A*STAR

Read more: Integrated lasers on different surfaces

Nanoparticulele polimerice fluorescente îndreaptă degetul spre urme de dispozitive explozive (Fluorescent polymer nanoparticles point the finger at traces of explosive devices )

Loturile de bombe ar putea fi contracarate cu ajutorul unui sistem portabil pentru detectarea urmelor de explozivi exploziva folosind nanoparticule polimerice fluorescente, dezvoltat de A * STAR. Imprimate pe hârtie, acești polimeri prezintă o performanță de detecție a explozivului mult mai robustă decât materialele anterioare cu proprietăți similare ( Polymer Chemistry , poli (trifenil ethene) și poli (tetraphenyl ethene): sinteza, proprietatea de emisie indusă de agregare și aplicarea ca hârtie senzori pentru detectarea efectivă a nitro-compușilor ” ).
Multe metode au fost dezvoltate pentru a detecta urme de explozivi de mare intensitate, cum ar fi trinitrotoluenul (TNT), dar majoritatea necesită instrumente analitice de laborator, cum ar fi detectorii de absorbție UV sau spectrometrele de masă, spune Jianwei Xu de la Institutul A * Engineering, care a condus lucrarea. „Ne-am propus să dezvoltăm o alternativă portabilă, rapidă, ieftină și foarte sensibilă”.

Posted: Sep 08, 2017

Fluorescent polymer nanoparticles point the finger at traces of explosive devices

(Nanowerk News) Bomb plots could be thwarted with the help of a portable system for detecting traces of high explosives using fluorescent polymer nanoparticles, developed by A*STAR. Coated on to paper, these polymers display an explosive-detection performance far more robust than previous materials with similar properties (Polymer Chemistry, „Poly(triphenyl ethene) and poly(tetraphenyl ethene): synthesis, aggregation-induced emission property and application as paper sensors for effective nitro-compounds detection”).
Many methods have been developed to detect traces of high explosives such as trinitrotoluene (TNT), but most require large, lab-based analytical instruments such as UV absorption detectors or mass spectrometers, says Jianwei Xu from the A*STAR Institute of Materials Research and Engineering, who led the work. “We aimed to develop a portable, quick, inexpensive and highly sensitive alternative.”
polymer-coated polymer readily could detect fingerprints contaminated with traces of four common high explosives
The polymer-coated polymer readily could detect fingerprints contaminated with traces of four common high explosives, including TNT.
Xu focused on fluorescent polymers whose light emission dims when exposed to vapors of molecules such as TNT that contain ‘nitro-groups’ — the nitrogen-rich structure that give high explosives their energetic properties.
Although explosive-detecting fluorescent polymers have been developed before, there have been obstacles to their practical use, Xu explains. Some lost part of their fluorescence in solid form through a process called aggregation-caused quenching. Others lacked the necessary porosity for explosives vapor penetration, only retaining an effective response when formed in layers of around 2.5 nanometers — so thin, the sensor would be very difficult to fabricate cheaply.
Xu and his colleagues have been developing polymers that, rather than losing their light emission in the solid state, become brighter, an effect known as aggregation-induced emission (AIE). “Our previous research demonstrated that porous films obtained from AIE active copolymers show a strong response to the vapor of nitro-compounds,” says Xu.
The team has now developed two new polymers, poly(triphenyl ethene) (PTriPE) and poly (tetraphenyl ethene) (PTPE), designed to maximize AIE, porosity and nitro group sensitivity. The polymers’ multiple bulky phenyl groups help keep them rigid and maximize light emission following aggregation. But in the presence of nitro-groups, electron transfer between polymer and analyte rapidly quenches the light.
“Paper sensors fabricated by absorbing the polymer nanoparticles on to filter paper showed high sensitivity for nitro-compound particles,” says Xu. PTriPE proved to be the pick of the pair, detecting TNT at a concentration of five parts per billion, even in polymer layers 1000 nanometers thick.
“This technology could be used at airports, ports and for border control for detecting explosives in any explosive-contaminated containers, clothing, boxes or bags,” says Xu. “We are seeking co-operation with industry to commercialize this technology.”
Source: A*STAR

Read more: Fluorescent polymer nanoparticles point the finger at traces of explosive devices

Cum pot fi direcționate bolile folosind nanotehnologia – și de ce este dificil( How diseases can be targeted using nanotechnology – and why it’s difficult)

anticorpul corect. Un antigen este legat de un anticorp. (Imagine: © ACS, Autor furnizat)
Aceste tipuri de nanoparticule pot funcționa bine în laborator, dar atunci când sunt utilizate în medii biologice mai complexe (cum ar fi în sânge, mai degrabă decât în ​​soluție tampon de sare), lucrurile devin rapid mai complicate.
De exemplu, atunci când nanoparticulele sunt injectate în sânge, proteinele se adsorb pe suprafața lor și acest lucru își poate schimba comportamentul complet ( Chem. , Rev. , „Corona biomoleculelor nanoparticule: lecții învățate – provocare acceptată?” ). Acest lucru se datorează faptului că această acoperire bio schimbă proprietățile importante ale particulelor, incluzând încărcarea (pozitivă, neutră sau negativă) și mărimea.Nanomaterialele administrate la o experiență de șoarece au multe niveluri diferite de complexitate biologică. Toate acestea trebuie luate în considerare la proiectarea nanomedicinei.

Posted: Sep 08, 2017

How diseases can be targeted using nanotechnology – and why it’s difficult

(Nanowerk News) Scientists are designing materials that are a thousand times smaller than the width of a hair. Known as nanomaterials or nanoparticles, some could help treat diseases.
However, the engineering of particles for biomedical applications remains challenging, particularly when moving from the test tube to biological environments.
This is an issue we discussed in a recent paper (Advanced Healthcare Materials, „Particle Targeting in Complex Biological Media”). A nanoparticle in the lab is one thing, but a nanoparticle interacting with blood, cells and tissues is another, and the behaviour of particles can change considerably when moving from one environment to another.
“Bio-nano interactions” are what govern these changes in behaviour, and this is a research area with plenty of difficulties, but also significant rewards.
layer-by-layer assembly - Using nanotechnology to prepare nanomaterials
Using nanotechnology to prepare nanomaterials. The example here is called layer-by-layer assembly. (© 2015 AAAS and 2016 ACS, Author provided)

Using nanoparticles to target diseases
Nanoparticles could help create more effective medical treatments. The aim is to improve areas ranging from drug delivery to the detection of diseases.
One of the potential benefits of nanoparticles is the possibility of developing targeted therapies, so that drugs go exactly where they are needed in the body.
For example, many highly effective chemo-therapeutics exist today, but because they do not interact only with cancer cells but with healthy ones too, many of them have side effects such as heart and bone marrow damage. This limits their efficacy and plays a big role in why treating cancer can be so difficult.

Why is targeting so hard?
But targeted drug therapies using nanoparticles also remain limited (ACS Central Science, „Does Nanomedicine Have a Delivery Problem?”). As in many other areas, what works in the laboratory can be difficult to translate into the clinic.
One example is the use of nanoparticles as “carriers” that are loaded with a drug and then accumulate at target cells (see image below).
Nanomaterials can be used to target specific cells
Nanomaterials can be used to target specific cells in the laboratory. In this image, they target/attach to the blue cells, but not to the green cells, and only when the correct antibody is used. An antigen is what an antibody binds to. (Image: © ACS, Author provided)
These types of nanoparticles can perform well in the laboratory, but when used in more complex biological environments (such as in blood rather than in salt buffer solution) things rapidly become more complicated.
For example, when nanoparticles are injected into blood, proteins adsorb onto their surface and this can completely change their behaviour (Chem. Soc. Rev., „The nanoparticle biomolecule corona: lessons learned – challenge accepted?”). This is because this bio-coating changes important properties of the particles, including charge (positive, neutral or negative) and size.

Possible solutions
New methods are being developed to evaluate nanoparticles in better ways. This includes investigative techniques that can complement cell and animal studies.
One example is microfluidic channels that can mimic blood vessels and can be used to study nanomaterial behaviour in blood capillaries.
Another option uses 3D printed tissues and organs. In one recent example, hydrogels filled with cells were printed onto a surface using a custom-built 3D printer.
The key point is to have adjustable complexity. That is, being able to adjust these methods so that we can get relevant and valuable information out of the studies. But not so complex that it becomes difficult to understand the mechanisms involved.
This is important, because a nanoparticle administered to an animal experiences several levels of biological complexity on its journey from the bloodstream to the target area (see image below). To understand fully what is happening, we need to study them all.
Nanomaterials administered to a mouse experience many different levels of biological complexity
Nanomaterials administered to a mouse experience many different levels of biological complexity. All of these need to be considered when designing nanomedicines. (Image: © ACS, Author provided)

Nanomedicines of tomorrow
The more we learn about bio-nano science – or how materials interact with biology on the nanoscale – the easier it will be to design nanoparticles that behave like we want them to.
After years of concerted efforts, a more clear picture of the mechanisms that determine how well a nanoparticle will work is emerging and the full extent of the challenge before us is starting to become clear.
It is unlikely that a single “quick fix” will be discovered.
Instead, research that manages to successfully combine ideas from different fields and researchers (JACS, „Increasing the Impact of Materials in and beyond Bio-Nano Science”) will likely lead to the development of new and improved targeted nanoparticles.
The aim is to provide new treatments for diseases that are difficult – or even impossible – to treat today.
Source: By Mattias Björnmalm, Marie Curie Research Fellow, Imperial College London and Frank Caruso, Professor and ARC Australian Laureate Fellow, University of Melbourne

Read more: How diseases can be targeted using nanotechnology – and why it’s difficult

Oamenii de știință dezvăluie noi perspective în materiale semiconductoare 2D promițătoare(Scientists unravel new insights into promising 2D semiconductor material )

au stabilit noi descoperiri cu privire la proprietatile disulfidului de molibden bidimensional (MoS 2 ), un semiconductor larg studiat al viitorului.MoS 2 – O alternativă la grafen
MoS 2 este un material semiconductor care prezintă proprietăți electronice și optice dorite pentru dezvoltarea și îmbunătățirea tranzistorilor, fotodetectoarelor și celulelor solare.structură similară cu MoS 2 .
„MoS 2 se încadrează într-un grup de materiale cunoscute sub numele de dihalcogenidele metalice de tranziție bidimensionale (2D-TMD) care prezintă un mare interes pentru cercetare din cauza potențialelor aplicații industriale. Noile cunoștințe din studiile noastre ne vor ajuta să deblocăm posibilitățile Aplicații bazate pe 2D-TMD, cum ar fi fabricarea de tranzistoare cu efect de câmp 2D-TMD „, a declarat Asst Prof Rusydi.
Folosind rezultatele acestor studii, cercetătorii vor aplica studii similare celorlalte 2D-TMD-uri și vor explora diferite posibilități de generare de proprietăți noi și valoroase în 2D-TMD care nu există în natură.

Posted: Sep 08, 2017

Scientists unravel new insights into promising 2D semiconductor material

(Nanowerk News) Researchers from the National University of Singapore (NUS) have established new findings on the properties of two-dimensional molybdenum disulfide (MoS2), a widely studied semiconductor of the future.
In two separate studies led by Professor Andrew Wee and Assistant Professor Andrivo Rusydi from the Department of Physics at the NUS Faculty of Science, the researchers uncovered the role of oxygen in MoS2, and a novel technique to create multiple tunable, inverted optical band gaps in the material. These novel insights deepen the understanding of the intrinsic properties of MoS2 which could potentially transform its applications in the semiconductor industry.
The studies were published in prestigious scientific journals Physical Review Letters and Nature Communications respectively.

MoS2 – An alternative to graphene
MoS2 is a semiconductor-like material that exhibits desirable electronic and optical properties for the development and enhancement of transistors, photodetectors and solar cells.
Prof Wee explained, „MoS2 holds great industrial importance. With an atomically thin two-dimensional structure and the presence of a 1.8eV energy band gap, MoS2 is a semiconductor that can offer broader applications than graphene which lacks a band gap.”

Presence of oxygen alters the electronic and optical properties of MoS2
In the first study published in Physical Review Letters on 16 August 2017 („Oxygen Passivation Mediated Tunability of Trion and Excitons in MoS2„), NUS researchers conducted an in-depth analysis which revealed that the energy storage capacity or dielectric function of MoS2 can be altered using oxygen.
The team observed that MoS2 displayed a higher dielectric function when exposed to oxygen. This new knowledge shed light on how adsorption and desorption of oxygen by MoS2 can be employed to modify its electronic and optical properties to suit different applications. The study also highlights the need for adequate consideration of extrinsic factors that may affect the properties of the material in future research.
The first author of this paper is Dr Pranjal Kumar Gogoi from the Department of Physics at NUS Faculty of Science.

MoS2 can possess two tunable optical band gaps
In the second study published in Nature Communications on 7 September 2017 („Tunable inverted gap in monolayer quasi-metallic MoS2 induced by strong charge-lattice coupling”), the team of NUS researchers discovered that as opposed to conventional semiconductors which typically have only one optical band gap, electron doping of MoS2 on gold can create two unusual optical band gaps in the material. In addition, the two optical bandgaps in MoS2 are tunable via a simple, straight forward annealing process.
The research team also identified that the tunable optical band gaps are induced by strong-charge lattice coupling as a result of the electron doping.
The first author of this second paper is Dr Xinmao Yin from the Department of Physics at NUS Faculty of Science.
The research findings from the two studies lend insights to other materials that possess similar structure with MoS2.
„MoS2 falls under a group of material known as the two-dimensional transitional metal dihalcogenides (2D-TMDs) which are of great research interest because of their potential industrial applications. The new knowledge from our studies will assist us in unlocking the possibilities of 2D-TMD-based applications such as the fabrication of 2D-TMD-based field effect transistors,” said Asst Prof Rusydi.
Leveraging the findings of these studies, the researchers will apply similar studies to other 2D-TMDs and to explore different possibilities of generating new, valuable properties in 2D-TMDs that do not exist in nature.
Source: National University of Singapore

Read more: Scientists unravel new insights into promising 2D semiconductor material

Evaluarea toxicității nanoclay(Assessing the toxicity of nanoclay)

„Modelul SAEC extinde impactul studiului nostru asupra unei platforme biologice mai umane, deoarece celulele primare imita mai mult țesutul lor de origine și reduc în continuare identificarea greșită, contaminarea, instabilitatea genetică generală și lipsa de funcții și markeri întâlnite adesea cu celulele imortalizate sisteme, „noteaza cercetatoriiCu o rată estimată de creștere de aproximativ 25% anual, nanocompozitele sau compozitele care conțin nanoclase încorporate în polimeri sunt de așteptat să aibă o largă implementare în produsele comerciale și industriale, de la materialele de ambalare pentru produsele alimentare la dispozitivele auto și medicale. În ambalajul alimentar, de exemplu, nanoclays sunt modificate organic pentru a permite o mai bună exfoliere în matricea polimerului la un procentaj scăzut în greutate silicat, ceea ce duce la aplicații comerciale de aproape 70% din volumul pieței.

Posted: Sep 07, 2017

Assessing the toxicity of nanoclay

(Nanowerk News) With an estimated growth rate of about 25% annually, nanocomposites or composites containing nanoclays incorporated into polymers are expected to have wide implementation in commercial and industrial products, from food packaging materials to automotive and medical devices. In food packaging, for instance, nanoclays are organically modified to allow for better exfoliation within the polymer matrix at a low silicate weight percent, leading to commercial applications of almost 70% of the market volume.
Some of the most common nanoclays used in food packaging are Nanomer I.31PS, Nanomer I.34TCN, and Nanomer I.44P. Researchers at West Virginia University now have designed a systematic study to help determine the potential for inhalation toxicity of the three organically modified Nanomer nanoclays currently used for food packaging applications.
This study, just reported in a paper in ACS Applied Materials & Interfaces („Early Assessment and Correlations of Nanoclay’s Toxicity to Their Physical and Chemical Properties”), uses human immortalized bronchial epithelial cells (BEAS-2B) and primary small airway epithelial cells (SAECs) as established cell lines for assessing toxicity induced via inhalation because they have previously helped assess toxicity of graphene nanoparticles, asbestos, and carbon nanotubes.
Assessment and Correlations of Nanoclay’s Toxicity to Their Physical and Chemical Properties
„The SAEC model expands the impact of our study to a more human-related biological platform as primary cells more closely mimic their tissue of origin and further reduce misidentification, contamination, general genetic instability, and lack of functions and markers often encountered with immortalized cellular systems,” the researchers note.
Additionally, through the use of two epithelial lung cell lines, the scientists were able to further assess the potential toxicity of nanoclays when they deposit in both the bronchioles and distal airways near the terminal bronchiole and alveolar duct, respectively.
Systematic assessment maps and correlates the physical and chemical properties of nanoclays at two points in their life cycle (i.e., production/manufacturing or the end of their life cycle) with their potential to induce toxicity for a better understanding of how nanoclays’ deleterious interactions with the cellular systems can be reduced so safe yet effective materials can be produced and implemented in commercial sectors.
„Our study showed that the chemical composition of individual organic modifiers used for nanoclay functionalization played a large role in their interactions with cellular systems,” the authors conclude their report. „Specifically, differences in organic modifiers caused differential size distributions in dispersion cellular media and differential degrees of toxicity upon their or thermally degraded byproducts exposure to lung epithelial cells. Understanding how the physical and chemical properties of such materials influence toxicity can aid in safer design functionalities while still maintaining beneficial properties to make them miscible with polymer matrixes for food packaging applications.”
By Michael is author of two books by the Royal Society of Chemistry: Nano-Society: Pushing the Boundaries of Technology and Nanotechnology: The Future is Tiny.

Read more: Assessing the toxicity of nanoclay