Materiale si echipamente cu proprietati noi in domeniul medical pentru proteze si inlocuitori de tesuturi – Pagina 4

Pielea asemănătoare cu pielea poate să se întindă, să atingă sens și să emită lumină(Octopus-like skin can stretch, sense touch, and emit light )

o piele artificiala care se poate intinde, simti presiunea si emite lumina,

Dispozitive electronice extensibile, care au o lungime cvadruple

ar putea fi folosit pentru senzori concepuți pentru a monitoriza anumite funcții biologice.Ideale pentru pielea artificială pe proteze sau mașini robotizateÎnlătură termen: îmbrăcăminte conectată și senzori pe corp îmbrăcăminte conectată și senzori pe corp

Posted: Feb 29, 2016
Stretchable electronics that quadruple in length (w/video) (Nanowerk News) EPFL researchers have developed conductive tracks that can be bent and stretched up to four times their original length. They could be used in artificial skin, connected clothing and on-body sensors.

Conductive tracks are usually hard printed on a board. But those recently developed at EPFL are altogether different: they are almost as flexible as rubber and can be stretched up to four times their original length and in all directions. And they can be stretched a million times without cracking or interrupting their conductivity. The invention is described in an article published today in the journal Advanced Materials („Intrinsically Stretchable Biphasic (Solid–Liquid) Thin Metal Films”).
Both solid and flexible, this new metallic and partially liquid film offers a wide range of possible applications. It could be used to make circuits that can be twisted and stretched – ideal for artificial skin on prosthetics or robotic machines. It could also be integrated into fabric and used in connected clothing. And because it follows the shape and movements of the human body, it could be used for sensors designed to monitor particular biological functions.
“We can come up with all sorts of uses, in forms that are complex, moving or that change over time,” said Hadrien Michaud, a PhD student at the Laboratory for Soft Bioelectronic Interfaces (LSBI) and one of the study authors.
Extensive research has gone into developing an elastic electronic circuit. It is a real challenge, as the components traditionally used to make circuits are rigid. Applying liquid metal to a thin film in polymer supports with elastic properties naturally seems like a promising approach.

Thin and reliable
Owing to the high surface tension of some of these liquid metals, experiments conducted so far have only produced relatively thick structures. “Using the deposition and structuring methods that we developed, it’s possible to make tracks that are very narrow – several hundredths of a nanometer thick – and very reliable,” said Stéphanie Lacour, holder of the Bertarelli Foundation Chair in Neuroprosthetic Technology and who runs the lab.
Apart from their unique fabrication technique, the researchers’ secret lies in the choice of ingredients, an alloy of gold and gallium.
“Not only does gallium possess good electrical properties, but it also has a low melting point, around 30o,” said Arthur Hirsch, a PhD student at LSBI and co-author of the study. “So it melts in your hand, and, thanks to the process known as supercooling, it remains liquid at room temperature, even lower.” The layer of gold ensures the gallium remains homogeneous, preventing it from separating into droplets when it comes into contact with the polymer, which would ruin its conductivity.

Source: By Sarah Perrin, École polytechnique fédérale de Lausanne (EPFL)

Sistemul de livrare a nanotehnologiei oferă o nouă abordare a terapiilor cu boli ale pielii

activeaza in mod eficient apararea naturala a organismului impotriva radicalilor liberi șnanotehnologie care contine un inductor de protectie celulara protectiva

Posted: Feb 29, 2016
Nanotechnology delivery system offers new approach to skin disease therapies (Nanowerk News) Researchers at The Hebrew University of Jerusalem have developed a nanotechnology-based delivery system containing a protective cellular pathway inducer that activates the body’s natural defense against free radicals efficiently, a development that could control a variety of skin pathologies and disorders.
The human skin is constantly exposed to various pollutants, UV rays, radiation and other stressors that exist in our day-to-day environment. When they filter into the body they can create Reactive Oxygen Species (ROS) – oxygen molecules known as Free Radicals, which are able to damage and destroy cells, including lipids, proteins and DNA.
In the skin – the largest organ of the body – an excess of ROS can lead to various skin conditions, including inflammatory diseases, pigmenting disorders, wrinkles and some types of skin cancer, and can also affect internal organs. This damage is known as Oxidative Stress.
The body is naturally equipped with defense mechanisms to counter oxidative stress. It has anti-oxidants and, more importantly, anti-oxidant enzymes that attack the ROS before they cause damage.
In a review article published in the journal Cosmetics („Skin Redox Balance Maintenance: The Need for an Nrf2-Activator Delivery System”), a PhD student from The Hebrew University of Jerusalem, working in collaboration with researchers at the Technion – Israel Institute of Technology, suggested an innovative way to invigorate the body to produce antioxidant enzymes, while maintaining skin cell redox balance – a gentle equilibrium between Reactive Oxygen Species and their detoxification.

Consequences of skin exposure to stressors (Image: Maya Ben-Yehuda Greenwald) (click on image to enlarge)
„The approach of using the body’s own defense system is very effective. We showed that activation of the body’s defense system with the aid of a unique delivery system is feasible, and may leverage dermal cure,” said Hebrew University researcher Maya Ben-Yehuda Greenwald.
Ben-Yehuda Greenwald showed that applying nano-size droplets of microemulsion liquids containing a cellular protective pathway inducer into the skin activates the natural skin defense systems.
„Currently, there are many scientific studies supporting the activation of the body’s defense mechanisms. However, none of these studies has demonstrated the use of a nanotechnology-based delivery system to do so,” Ben-Yehuda Greenwald said.
Production of antioxidant enzymes in the body is signaled in the DNA by activation of Nrf2 – a powerful protein that exists in every cell in our body. This Nrf2 cellular-protective signaling pathway is a major intersection of many other signaling pathways affecting each other and determining cell functionality and fate. Nrf2 is capable of coordinating the cellular response to internal as well as external stressors by tight regulation of phase-II protective enzymes, such as the antioxidant enzymes.
Ben-Yehuda Greenwald has also discovered a new family of compounds capable of activating the Nrf2 pathway. Moreover, by incorporating them into the unique delivery system she has developed, she managed to efficiently stimulate the activation of the Nrf2 pathway and mimic the activity of the body’s’ natural way of coping with a variety of stress conditions.
„The formula we have created could be used in topical medication for treating skin conditions. Our formula could be used both as preventive means and for treatment of various skin conditions, such as infections, over-exposure to UV irradiation, inflammatory conditions, and also internal disease,” she said.
While the researchers focused on the skin, the formulation could prove to be effective in enhancing the body’s natural protection against the damaging effects of ROS in other parts of the body, such as inflammation in cardiovascular diseases, heart attack, cancer, multiple sclerosis and Alzheimer’s.

Source: Hebrew University of Jerusalem

Temperatura corpului declanșează polimerul nou dezvoltat pentru a schimba forma (Body temperature triggers newly-developed polymer to change shape )

un tip de polimer cu formă de memorie, care poate fi programat să păstreze o formă temporară până când este declanșat – de obicei prin căldură – pentru a reveni la forma sa originală.Anthamatten afirmă că polimerul cu formă de memorie ar putea avea o varietate de aplicații, inclusiv suturi, piele artificială, dozatoare medicale asistate de căldură și articole de îmbrăcăminte auto-asamblată.

Posted: Feb 09, 2016
Body temperature triggers newly-developed polymer to change shape (Nanowerk News) The material developed by Anthamatten and graduate student Yuan Meng is a type of shape-memory polymer, which can be programmed to retain a temporary shape until it is triggered—typically by heat—to return to its original shape.
“Tuning the trigger temperature is only one part of the story,” said Anthamatten. “We also engineered these materials to store large amount of elastic energy, enabling them to perform more mechanical work during their shape recovery”
The findings are being published this week in the Journal of Polymer Science Part B: Polymer Physics („Body temperature triggered shape-memory polymers with high elastic energy storage capacity”).

A time-lapse photo of a new shape-memory polymer reverting to its original shape after being exposed to body temperature.
The key to developing the new polymer was figuring out how to control crystallization that occurs when the material is cooled or stretched. As the material is deformed, polymer chains are locally stretched, and small segments of the polymer align in the same direction in small areas—or domains—called crystallites, which fix the material into a temporarily deformed shape. As the number of crystallites grows, the polymer shape becomes more and more stable, making it increasingly difficult for the material to revert back to its initial—or “permanent”—shape.
The ability to tune the trigger temperature was achieved by including molecular linkers to connect the individual polymer strands. Anthamatten’s group discovered that linkers inhibit—but don’t stop—crystallization when the material is stretched. By altering the number and types of linkers used, as well as how they’re distributed throughout the polymer network, the Rochester researchers were able to adjust the material’s stability and precisely set the melting point at which the shape change is triggered.
Heating the new polymer to temperatures near 35 °C, just below the body temperature, causes the crystallites to break apart and the material to revert to its permanent shape.
“Our shape-memory polymer is like a rubber band that can lock itself into a new shape when stretched,” said Anthamatten. “But a simple touch causes it to recoil back to its original shape.”
Having a polymer with a precisely tunable trigger temperature was only one objective. Of equal importance, Anthamatten and his team wanted the material to be able to deliver a great deal of mechanical work as the shape transforms back to its permanent shape. Consequently, they set out to optimize their polymer networks to store as much elastic energy as possible.
“Nearly all applications of shape memory polymers will require that the material pushes or pulls on its surroundings,” said Anthamatten. “However, researchers seldom measure the amount of mechanical work that shape-memory polymers are actually performing.”
Anthamatten’s shape-memory polymer is capable of lifting an object one-thousand times its weight. For example, a polymer the size of a shoelace—which weighs about a gram—could lift a liter of soda.
Anthamatten says the shape-memory polymer could have a variety of applications, including sutures, artificial skin, body-heat assisted medical dispensers, and self-fitting apparel.

Source: University of Rochester

Stretchable electronics that quadruple in length (w/video)

Nanotechnology delivery system offers new approach to skin disease therapies

Body temperature triggers newly-developed polymer to change shape