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News Article | November 7, 2016
Site: globenewswire.com

EAST HARTFORD, Conn., Nov. 7, 2016 (GLOBE NEWSWIRE) -- The Connecticut Center for Advanced Technology Inc. (CCAT) was named an Environmental Partner Finalist for the 2013-2016 Environmental Leadership Award by the University of Connecticut Environmental Policy Advisory Council at an awards ceremony on October 25, 2016. The award distinguishes CCAT's dedication and contribution to environmental sustainability at UConn. The Environmental Leadership Awards were created by the university as a way to honor individuals as well as UConn-affiliated groups that have truly excelled in their efforts to contribute to environmental awareness and promote progress through their 'green' programs. According to the University of Connecticut Environmental Policy Advisory Council, CCAT was recognized for developing a Preliminary Feasibility Study and Strategic Deployment Plan for Renewable & Sustainable Energy Projects at the UConn campus in Storrs. "We are proud to be recognized by UConn for our work in supporting and expanding the university's renewable and sustainable energy efforts," stated Joel Rinebold, energy director, CCAT. "We look forward to continuing our collaboration with the university to spur the use of new energy technologies that will contribute to increased power and cost savings well into the future." The plan identified and assessed target locations for the development of 12 demonstration-scale renewable and sustainable energy projects for technologies, including solar thermal, solar photovoltaic, wind, fuel cells, geothermal, and biofuels. The deployment of renewable energy systems, as detailed in the plan, could support research efforts for power system planning, and integration of clean and renewable technologies into a smart grid. CCAT also assisted UConn by providing information and coordinating the development of the project feasibility application for the state's Microgrid Grant and Loan Pilot Program. CCAT is working with UConn to identify potential locations for hydrogen refueling stations at or near biomass sites that could potentially be used by state or other public or private-sector vehicle fleets. The potential sources of hydrogen would support zero-emission, fuel cell electric vehicles to increase transportation efficiency, improve environmental performance, increase economic development, and create new jobs. CCAT continues to team with the Center for Clean Energy Engineering (C2E2), the Institute for Materials Science, and others at UConn to consider anaerobic digestion, manufacturing supply chain, hydrogen production, materials/catalysts development, and use of renewables (wind) at UConn facilities. About CCAT Connecticut Center for Advanced Technology Inc. (CCAT) is a nonprofit organization, headquartered in East Hartford, Conn., that creates and executes bold ideas advancing applied technologies, IT strategies, energy solutions, STEM education, and career development. By leading state, regional, and national partnerships, CCAT helps manufacturers, academia, government and nonprofit organizations excel. Learn more at ccat.us, or follow CCAT on Twitter - @CCATInc.


Suffner J.,TU Darmstadt | Suffner J.,Karlsruhe Institute of Technology | Kaserer S.,Institute for Materials Science | Hahn H.,TU Darmstadt | And 3 more authors.
Advanced Energy Materials | Year: 2011

Sb-doped SnO 2 (ATO) is used as an alternative support material to replace carbon in the highly corrosive environment of a fuel cell cathode. Two ATO powders with different morphologies are decorated with Pt nanoparticles and afterwards used as the cathode catalyst. The commercial ATO powder exhibits crystallites in the nanometer range, while the home-made ATO powder, which was synthesized by ultrasonic spray pyrolysis, consists of polycrystalline hollow spheres. The spheres have diameters in the micrometer range and are composed of individual nanocrystallites. The unusual morphology of the home-made ATO offers nano- and microporosity at the same time and opens up new possibilities for the controlled design of electrode structures in low-temperature polymer electrolyte fuel cells. Both materials are characterized by XRD, SEM, and TEM and tested in a single cell set-up. While almost no current is gained from the membrane electrode assembly with the commercial ATO support, the cell with the home-made ATO achieves a mediocre performance. This higher activity, however, is obtained with approximately half the Pt content compared to the catalyst with the commercial support. The different behaviours of both ATO powders can therefore mainly be attributed to differences in the specific support morphology. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


News Article | February 22, 2017
Site: www.eurekalert.org

LOS ALAMOS, N.M., Feb. 22, 2017--In a new study published today in the journal PLOS ONE, Los Alamos National Laboratory scientists have taken a condensed matter physics concept usually applied to the way substances such as ice freeze, called "frustration," and applied it to a simple social network model of frustrated components. They show that inequality of wealth can emerge spontaneously and more equality can be gained by pure initiative. It's a computer-modeling exploration of the 19th-century Horatio Alger theme, whereby a motivated young person overcomes poor beginnings and lives the "rags to riches" life thanks to strength of character. "Most theories of wealth inequality rely on social stratification due to income inequality and inheritance," said Cristiano Nisoli, of the Physics of Condensed Matter and Complex Systems group at Los Alamos and lead author of the study. "We consider, however, the possibility that in our more economically fluid world, novel, direct channels for wealth transfer could be available, especially for financial wealth." The work stems from Los Alamos research into computational material science, with broader applications to materials physics, energy security and weapons physics. In this case, the study's authors used computer modeling to conceptualize the situation of a set of agents, endowed with opportunities to acquire available wealth. As Nisoli describes it, "we assume that the possession of wealth endows the user with the power to attract more wealth." The team of Benoit Mahault (visiting from Université Paris Saclay), Avadh Saxena and Nisoli divided the problem into three sets of problems: The first set of results shows that in a static society--where the allocation of opportunities does not change in time--the "law of the jungle" allows anyone to gain wealth from or lose it to anyone else. Relative chaos ensues. The second set of results also pertains to static societies, but ones in which transactions of wealth are regulated. People cannot gain or lose wealth from just anybody, but only from their neighbors in the network in which they are linked. This scenario leads to substantially more fairness in the mathematical benchmark cases of Erdös models for random networks and of Barabasi-Albert algorithms for scale-free networks. However, marked differences between the two appear when it comes to overall rather than subjective fairness. The third set of results pertains to dynamic societies. Maintaining the overall wealth level as fixed, the researchers allow agents to freely shift links among themselves as their own initiative drives them. This is where the concepts of power, frustration and initiative, previously benchmarked on static markets, become crucial. Their interplay results in a complex dynamic. At a low level of initiative, results converge to more or less ameliorated inequality where the power of wealth concentrates and wins. At high initiative levels, results converge to strong equality where power never concentrates. For initiative levels somewhere in between, we see the interplay of three emergent social classes: lower, middle and upper. Said Nisoli, "If driven by power alone, the market evolution reaches a static equilibrium characterized by the most savage inequality. Power not only concentrates wealth, but reshapes the market topology to concentrate the very opportunities to acquire wealth on only a few agents, who now amass all the wealth of the society." This equilibrium scenario however, does not take into account personal frustration and initiative to act. If those elements are introduced, at sufficient initiative, a cyclical dynamic of three social classes emerges. "Periodically, a long 'time of inequality' is contrasted by the patient effort of the middle class to rise up, to bring down the upper class and to merge with it. When that finally happens, however, the situation proves unstable: a single egalitarian class forms for a brief time, only to be soon disrupted by the appearance of difficult-to-predict 'black swan' economic events. The power of the latter, now competing against unfrustrated and thus demotivated agents of an egalitarian class, wins easily and a new time of inequality is brought in as a new middle class emerges while the upper-class rises," Nisoli explained. To encapsulate the concept, he said, "We learn from this analysis that in our admittedly simplified model, equality can be improved either by proper engineering of a static market topology, which seems impracticable, or by dynamic emergent reshaping of the market via sufficient individual initiative to act upon frustration." But a successful society, with reduced frustration and improved equality, does not continue for long. "Equality is short lived, we find, as the disappearance of frustration that follows equality removes the fundamental drive toward equality. Perhaps a key element in preventing the cyclical return of inequality would be memory, which is absent from our framework. But then, is it present in a real society?" The paper, "Emergent Inequality and Self-Organized Social Classes in a Network of Power and Frustration," appears in this week's PLOS ONE. Link: http://journals. This research was funded by the U.S. Department of Energy, the Los Alamos National Laboratory Center for Nonlinear Studies, the Los Alamos Institute for Materials Science and Laboratory Directed Research and Development. Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, BWX Technologies, Inc. and URS Corporation for the Department of Energy's National Nuclear Security Administration. Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health and global security concerns.


Through this "nanoscale-sculpturing" process, metals such as aluminium, titanium, or zinc can permanently be joined with nearly all other materials, become water-repellent, or improve their biocompatibility. The potential spectrum of applications of these "super connections" is extremely broad, ranging from metalwork in industry right through to safer implants in medical technology. Their results have now been published in the prestigious journal Nanoscale Horizons of the Royal Society of Chemistry. "We have now applied a technology to metals that was previously only known from semiconductors. To use this process in such a way is completely new," said Dr. Jürgen Carstensen, co-author of the publication. In the process, the surface of a metal is converted into a semiconductor, which can be chemically etched and thereby specifically modified as desired. "As such, we have developed a process which - unlike other etching processes - does not damage the metals, and does not affect their stability," emphasised Professor Rainer Adelung, head of the "Functional Nanomaterials" team at the Institute for Materials Science. Adelung stressed the importance of the discovery: "In this way, we can permanently connect metals which could previously not be directly joined, such as copper and aluminium." How does the "nanoscale-sculpturing" process work exactly? The surfaces of metals consist of many different crystals and grains, some of which are less chemically stable than others. These unstable particles can be specifically removed from the surface of a metal by a targeted etching. The top surface layer is roughened by the etching process, creating a three-dimensional surface structure. This changes the properties of the surface, but not of the metal as a whole. This is because the etching is only 10 to 20 micrometers deep - a layer as thin as a quarter of the diameter of human hair. The research team has therefore named the process "nanoscale-sculpturing". The change due to etching is visible to the naked eye: the treated surface becomes matt. "If, for example, we treat a metal with sandpaper, we also achieve a noticeable change in appearance, but this is only two-dimensional, and does not change the characteristics of the surface," explained Dr. Mark-Daniel Gerngross of the research team on materials sciences from Kiel. Through the etching process, a 3D-structure with tiny hooks is created. If a bonding polymer is then applied between two treated metals, the surfaces inter-lock with each other in all directions like a three-dimensional puzzle. "These 3-D puzzle connections are practically unbreakable. In our experiments, it was usually the metal or polymer that broke, but not the connection itself," said Melike Baytekin-Gerngross, lead author of the publication. Even a thin layer of fat, such as that left by a fingerprint on a surface, does not affect the connection. "In our tests, we even smeared gearbox oil on metal surfaces. The connection still held," explained Baytekin-Gerngross. Laborious cleaning of surfaces, such as the pre-treatment of ships' hulls before they can be painted, could thus be rendered unnecessary. In addition, the research team exposed the puzzle connections to extreme heat and moisture, to simulate weather conditions. This also did not affect their stability. Carstensen emphasised: "Our connections are extremely robust and weather-resistant." A beneficial side-effect of the process is that the etching makes the surfaces of metal water-repellent. The resulting hook structure functions like a closely-interlocked 3D labyrinth, without holes which can be penetrated by water. The metals therefore possess a kind of built-in corrosion protection. "We actually don't know this kind of behaviour from metals like aluminium. A lotus effect with pure metals, i.e. without applying a water-repellent coating, that is new," said Adelung. "The range of potential applications is extremely broad, from metalworking industries such as ship-building or aviation, to printing technology and fire protection, right through to medical applications," said Gerngross. Because the "nanoscale-sculpturing" process not only creates a 3D surface structure, which can be purely physically bonded without chemicals, the targeted etching can also remove harmful particles from the surface, which is of particularly great interest in medical technology. Titanium is often used for medical implants. To mechanically fix the titanium in place, small quantities of aluminium are added. However, the aluminium can trigger undesirable side-effects in the body. "With our process, we can remove aluminium particles from the surface layer, and thereby obtain a significantly purer surface, which is much more tolerable for the human body. Because we only etch the uppermost layer on a micrometer scale, the stability of the whole implant remains unaffected," explained Carstensen. The researchers have so far applied for four patents for the process. Businesses have already shown substantial interest in the potential applications. "And our specialist colleagues in materials sciences have also reacted enthusiastically to our discoveries," said a delighted Adelung. Explore further: New generation of orthopedic, dental and cardiovascular prostheses More information: M. Baytekin-Gerngross et al, Making metal surfaces strong, resistant, and multifunctional by nanoscale-sculpturing, Nanoscale Horiz. (2016). DOI: 10.1039/C6NH00140H


News Article | September 13, 2016
Site: www.nanotech-now.com

Home > Press > Breakthrough in materials science: Kiel research team can bond metals with nearly all surfaces Abstract: Through this "nanoscale-sculpturing" process, metals such as aluminium, titanium, or zinc can permanently be joined with nearly all other materials, become water-repellent, or improve their biocompatibility. The potential spectrum of applications of these "super connections" is extremely broad, ranging from metalwork in industry right through to safer implants in medical technology. Their results have now been published in the prestigious journal Nanoscale Horizons of the Royal Society of Chemistry. "We have now applied a technology to metals that was previously only known from semiconductors. To use this process in such a way is completely new," said Dr. Jürgen Carstensen, co-author of the publication. In the process, the surface of a metal is converted into a semiconductor, which can be chemically etched and thereby specifically modified as desired. "As such, we have developed a process which - unlike other etching processes - does not damage the metals, and does not affect their stability," emphasised Professor Rainer Adelung, head of the "Functional Nanomaterials" team at the Institute for Materials Science. Adelung stressed the importance of the discovery: "In this way, we can permanently connect metals which could previously not be directly joined, such as copper and aluminium." How does the "nanoscale-sculpturing" process work exactly? The surfaces of metals consist of many different crystals and grains, some of which are less chemically stable than others. These unstable particles can be specifically removed from the surface of a metal by a targeted etching. The top surface layer is roughened by the etching process, creating a three-dimensional surface structure. This changes the properties of the surface, but not of the metal as a whole. This is because the etching is only 10 to 20 micrometers deep - a layer as thin as a quarter of the diameter of human hair. The research team has therefore named the process "nanoscale-sculpturing". The change due to etching is visible to the naked eye: the treated surface becomes matt. "If, for example, we treat a metal with sandpaper, we also achieve a noticeable change in appearance, but this is only two-dimensional, and does not change the characteristics of the surface," explained Dr. Mark-Daniel Gerngross of the research team on materials sciences from Kiel. Through the etching process, a 3D-structure with tiny hooks is created. If a bonding polymer is then applied between two treated metals, the surfaces inter-lock with each other in all directions like a three-dimensional puzzle. "These 3-D puzzle connections are practically unbreakable. In our experiments, it was usually the metal or polymer that broke, but not the connection itself," said Melike Baytekin-Gerngross, lead author of the publication. Surfaces with multifunctional properties Even a thin layer of fat, such as that left by a fingerprint on a surface, does not affect the connection. "In our tests, we even smeared gearbox oil on metal surfaces. The connection still held," explained Baytekin-Gerngross. Laborious cleaning of surfaces, such as the pre-treatment of ships' hulls before they can be painted, could thus be rendered unnecessary. In addition, the research team exposed the puzzle connections to extreme heat and moisture, to simulate weather conditions. This also did not affect their stability. Carstensen emphasised: "Our connections are extremely robust and weather-resistant." A beneficial side-effect of the process is that the etching makes the surfaces of metal water-repellent. The resulting hook structure functions like a closely-interlocked 3D labyrinth, without holes which can be penetrated by water. The metals therefore possess a kind of built-in corrosion protection. "We actually don't know this kind of behaviour from metals like aluminium. A lotus effect with pure metals, i.e. without applying a water-repellent coating, that is new," said Adelung. Potentially limitless applications "The range of potential applications is extremely broad, from metalworking industries such as ship-building or aviation, to printing technology and fire protection, right through to medical applications," said Gerngross. Because the "nanoscale-sculpturing" process not only creates a 3D surface structure, which can be purely physically bonded without chemicals, the targeted etching can also remove harmful particles from the surface, which is of particularly great interest in medical technology. Titanium is often used for medical implants. To mechanically fix the titanium in place, small quantities of aluminium are added. However, the aluminium can trigger undesirable side-effects in the body. "With our process, we can remove aluminium particles from the surface layer, and thereby obtain a significantly purer surface, which is much more tolerable for the human body. Because we only etch the uppermost layer on a micrometer scale, the stability of the whole implant remains unaffected," explained Carstensen. The researchers have so far applied for four patents for the process. Businesses have already shown substantial interest in the potential applications. "And our specialist colleagues in materials sciences have also reacted enthusiastically to our discoveries," said a delighted Adelung. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | January 14, 2016
Site: phys.org

Investigations using an atomic force microscope showed that the cell adhesion can be turned on and off in a controlled manner. In the photo (from the left): Christine Selhuber-Unkel, Laith Kadem and Rainer Herges. Credit: Denis Schimmelpfennig, Kiel University A cell is rarely on its own, because cells require good contacts to communicate with one another, to differentiate from others and to multiply. For this, cells have developed sophisticated mechanisms, the details of which are still widely unknown. In order to get a little closer towards unravelling the mystery of cell adhesion, the two chemists, Michelle Holz and Grace Suana, inserted a light-sensitive switch into molecules which cells like to adhere to, and then attached these to a glass surface. If this surface is then exposed to even a few seconds of UV light, the 'adhesion molecules' pull back and the cells can only attach themselves with difficulty. Irradiation with visible light reverses the process and the cells join together with the molecules again. "In our model system we are able to control when and where cells adhere to in an extremely precise way", says Professor Rainer Herges from the Otto Diels Institute of Organic Chemistry. The scientists used an atomic force microscope to test the system. This device is so sensitive that it is possible to determine the minute adhesive power of a single cell with great precision. Professor Christine Selhuber-Unkel and her doctoral candidate, Laith Kadem, from the Institute for Materials Science attached living connective tissue cells to a tiny, movable metal needle and detected its adhesive power to the switchable surfaces. This enabled them to verify the surfaces' switching function. These research findings from Kiel could help us to optimise the use of cell cultures in future. After they have grown on the surfaces, the cells are often mechanically 'harvested'. This rough treatment often causes lots of cells to die, making the culture useless for medical application. This more gentle removal using light could help solve this problem. Precisely controllable, non-invasive procedures are particularly advantageous in cell breeding in computer-controlled biochips. This work results from the Collaborative Research Centre (CRC) 677 ''Function by Switching'', funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG). Over 100 scientists worked on this showcase project in Kiel to develop switchable molecular machines. More information: Laith F. Kadem et al. Rapid Reversible Photoswitching of Integrin-Mediated Adhesion at the Single-Cell Level, Advanced Materials (2015). DOI: 10.1002/adma.201504394


Avasthi D.K.,Inter University Accelerator Center | Mishra Y.K.,Institute for Materials Science | Singh F.,Inter University Accelerator Center | Stoquert J.P.,Institute of Electronics of Solids and Systems
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

Swift heavy ions have unique feature of creating ion tracks in insulators of dimension from a few nm to about 10 nm. This particular feature of the swift heavy ions is used to engineer the size and shape of the nanoparticles embedded in silica matrix. On the basis of several experiments, it is evidenced that the embedded nanoparticles either grow in size or reduce in size, if they are smaller than or comparable to the ion track size. The shape transformation from spherical to elongated along the beam direction occurs, when the nanoparticle size is larger than the ion track diameter in silica. The reduction, growth and elongation of Au nanoparticles embedded in silica matrix under swift heavy ion irradiation have been discussed in the frame work of thermal spike model. © 2010 Elsevier B.V. All rights reserved.


« Ricardo supplying single-cylinder diesel research engine with TVCS to DongFeng Commercial Vehicles | Main | Jaguar unveils Formula E team’s official name, title sponsor, driver line-up and electric racing livery » Researchers at the University of Kiel (Germany) have developed a new process—which they call “nanoscale-sculpturing”—for the surface preparation of metals. Nanoscale-sculpturing, which is based on knowledge from semiconductor etching, turns surfaces of everyday metals into their most stable configuration, but leaves the bulk properties unaffected. Thus, nanoscale-sculpturing ensures stronger, reliable joints to nearly all materials, reduces corrosion vastly, and generates a multitude of multifunctional surface properties. An open-access paper on their work is published in the RSC journal Nanoscale Horizons. In strong contrast to nearly all relevant technical surface treatments on metals and semiconductors, the sculpturing approach utilizes the intrinsic features of the surface-near grain structure on the nanoscale. The (electro-)chemistry is tuned to selectively etch out entire or at least large parts of grains on the nanolevel in a coordinated manner introducing an intrinsic micro 3D-character into the resulting surfaces. Deep cavities with undercuts allowing for mechanical interlocking are thus an intrinsic feature of sculpturing. Due to the 3D-character the preserved grains, plains, and facets, i.e., the bulk structure is extremely stable, since, e.g., no grain boundaries are widened weakening the surface microstructure. The surfaces of metals consist of many different crystals and grains, some of which are less chemically stable than others. These unstable particles can be specifically removed from the surface of a metal by a targeted etching. The top surface layer is roughened by the etching process, creating a three-dimensional surface structure. This changes the properties of the surface, but not of the metal as a whole. This is because the etching is only 10 to 20 micrometers deep—a layer as thin as a quarter of the diameter of human hair. The research team has therefore named the process “nanoscale-sculpturing”. To use this process in such a way is completely new, said Dr. Jürgen Carstensen, co-author of the publication. As such, we have developed a process which—unlike other etching processes—does not damage the metals, and does not affect their stability. In this way, we can permanently connect metals which could previously not be directly joined, such as copper and aluminium. —Professor Rainer Adelung, head of the Functional Nanomaterials team at the Institute for Materials Science The change due to etching is visible to the naked eye: the treated surface becomes matt. Through the etching process, a 3D-structure with tiny hooks is created. If a bonding polymer is then applied between two treated metals, the surfaces inter-lock with each other in all directions like a three-dimensional puzzle. Even a thin layer of fat, such as that left by a fingerprint on a surface, does not affect the connection. The researchers even smeared gearbox oil on metal surfaces, and found that the connection still held, said Baytekin-Gerngroß. Laborious cleaning of surfaces, such as the pre-treatment of ships’ hulls before they can be painted, could thus be rendered unnecessary. Extreme heat and moisture also did not affect the joins. A beneficial side-effect of the process is that the etching makes the surfaces of metal water-repellent. The resulting hook structure functions like a closely-interlocked 3D labyrinth, without holes which can be penetrated by water. The metals therefore possess a kind of built-in corrosion protection. Because the nanoscale-sculpturing process not only creates a 3D surface structure which can be purely physically bonded without chemicals, the targeted etching can also remove harmful particles from the surface, which is of particularly great interest in medical technology. The researchers have so far applied for four patents for the process. Businesses have already shown substantial interest in the potential applications.


News Article | December 20, 2016
Site: phys.org

Irradiation with green light from below induces a vibration of the signalling molecules (RGD). This mechanical stimulus causes the cells to adhere to the surface. Credit: Rainer Herges Everyone is made up of approximately 100 trillion cells – if they were laid end to end, they would circle the globe 60 times. Most of these cells arise from mitosis and differentiation of a single egg cell. To orientate themselves, they constantly explore their environment and communicate with their neighbours while they adhere to other cells or surfaces. Two working groups from the fields of chemistry and biophysics at Kiel University have discovered a new method for stimulating cells, thereby increasing their adhesion. The results now appear in the renowned journal Angewandte Chemie. Cells are permanently under attack by bacteria that are attempting to infiltrate them. By contrast, useful bacteria aid digestion or live peacefully on human skin. Cells must communicate continuously and probe their environment to identify friend or foe, or to differentiate themselves from their neighbouring cells. This is why they seek out direct contact with other cells or to their environment. 'If individual cells are floating in a solution and encounter a surface, they first probe the area to determine whether it is a suitable location to settle. If this is the case, they extend protein sensors to attach themselves. Other cells follow suit, which creates cellular tissue,' explains Rainer Herges, professor at the Institute of Organic Chemistry. Cells adhere faster if they are stimulated Research has long shown that cells respond selectively to certain surface structures and their chemical composition. There are indications that, in addition to static stimuli, dynamic processes such as movements and mechanical forces also have an attracting effect on cells. If, for example, a fine needle is used to tug at cells, this stimulates them to increase their adhesion. 'However, this is not a very subtle, controlled method, since a large number of different cellular processes are affected,' reports Christine Selhuber-Unkel, professor for biocompatible nanomaterials at the Institute for Materials Science at Kiel University. The method that Selhuber-Unkel and Herges now have discovered for stimulating cells is much more sophisticated. They bind chemical recognition structures (so-called RGDs), which are recognised by cells, to surfaces. However, these signalling molecules do not stand stiff on the surface; instead, they can be moved with light. Tiny molecular switches are incorporated into the tether that binds the RGDs to the surfaces. These molecules bend back and forth approximately 1,000 times per second when they are irradiated with green light. 'This vibration is transferred to the RGDs, which in turn "pluck" at the cells. The cells appear to perceive this type of stimulation: they adhere faster and more strongly to the surface,' explains Selhuber-Unkel. This adhesion strength is measured using an atomic force microscope. The fact that there is increased production of adhesion proteins also indicates that the cells react to this stimulus. The discovery by the researchers in Kiel could trigger a multitude of potential applications. The molecular vibrators can be directly incorporated into cell membranes, which would allow cells to be controlled with light. 'Use of light as a type of "nanoscalpel" is also conceivable in the long-term; light could be employed to perform extremely precise, microscopic, surgical interventions', Herges continues. Research on how to use light to indirectly stimulate cells via molecular switches has been a topic at the Collaborative Research Centre 677 'Function by Switching' since several years. 'Using light for stimulation has a number of advantages. Firstly, it can be switched on and off in a controlled way,' explains Herges, the head of the SFB. 'Moreover, using a laser cells can be irradiated with a resolution of 300 nanometres to detect which areas on the cell are responsible for adhesion. Thereby, we can elucidate the mechanisms of cellular adhesion.' Interdisciplinary cooperation was initiated by the framework of the CRC 677. Michelle Holz and Grace Suana from Rainer Herges' working group in the organic chemistry institute synthesised the switching molecules and surfaces. Laith F. Kadem from Christine Selhuber-Unkel's working group conducted the cell experiments. More information: Laith F. Kadem et al. High-Frequency Mechanostimulation of Cell Adhesion, Angewandte Chemie International Edition (2016). DOI: 10.1002/anie.201609483


News Article | September 14, 2016
Site: www.materialstoday.com

How metals can be used depends on the characteristics of their surfaces. A research team at Kiel University’s Institute for Materials Science in Germany has now developed a way to change these surface characteristics without affecting the mechanical stability of the metals or changing the metal characteristics themselves. This fundamentally new method utilizes an electro-chemical etching process to roughen the uppermost layer of a metal on a micrometer scale in a tightly-controlled manner. Through this ‘nanoscale-sculpturing’ process, metals such as aluminum, titanium or zinc can permanently be joined with nearly all other materials, and can also be made water-repellent or more biocompatible. This process, which is described in a paper in Nanoscale Horizons, could thus have a broad range of applications, from metalwork in industry right through to safer implants in medical technology. “We have now applied a technology to metals that was previously only known from semiconductors. To use this process in such a way is completely new,” said Jürgen Carstensen, co-author of the paper. “As such, we have developed a process which – unlike other etching processes – does not damage the metals, and does not affect their stability,” explained Rainer Adelung, head of the Functional Nanomaterials team at the Institute for Materials Science. “In this way, we can permanently connect metals which could previously not be directly joined, such as copper and aluminum.” The surfaces of metals consist of many different crystals and grains, some of which are less chemically stable than others. These unstable particles can be specifically removed from the surface of a metal by targeted etching, which roughens the top surface layer of the metal to create a three-dimensional (3D) surface structure. This changes the properties of the surface, but not of the metal as a whole. This is because the etching is only 10–20µm deep, leading the research team to name the process ‘nanoscale-sculpturing’. The change due to etching is visible to the naked eye: the treated surface becomes matt. “If, for example, we treat a metal with sandpaper, we also achieve a noticeable change in appearance, but this is only two-dimensional and does not change the characteristics of the surface,” explained Mark-Daniel Gerngroß, another co-author of the paper. The etching process produces a 3D structure with tiny hooks. If a bonding polymer is then applied between two treated metals, their surfaces inter-lock with each other in all directions like a 3D puzzle. “These 3D puzzle connections are practically unbreakable. In our experiments, it was usually the metal or polymer that broke, but not the connection itself,” said Melike Baytekin-Gerngroß, lead author of the paper. Even a thin layer of fat – such as that left by a fingerprint on a surface – does not affect the connection. “In our tests, we even smeared gearbox oil on metal surfaces. The connection still held,” explained Baytekin-Gerngroß. Laborious cleaning of surfaces, such as applied to ships' hulls before they can be painted, could thus be rendered unnecessary. In addition, the research team exposed the puzzle connections to extreme heat and moisture, in order to simulate weather conditions; this also did not affect their stability. “Our connections are extremely robust and weather-resistant,” said Carstensen. A beneficial side-effect of the process is that the etching makes the metal surfaces water-repellent. The resulting hook structure functions like a closely-interlocked 3D labyrinth, without holes that can be penetrated by water, giving the metals a kind of built-in corrosion protection. “We actually don't know this kind of behavior from metals like aluminum. A lotus effect with pure metals – i.e. without applying a water-repellent coating – that is new,” said Adelung. “The range of potential applications is extremely broad, from metalworking industries such as ship-building or aviation, to printing technology and fire protection, right through to medical applications,” said Gerngroß. Not only can the ‘nanoscale-sculpturing’ process create a 3D surface structure that can be physically bonded without chemicals, but it can also remove harmful particles from the surface, which could be of particular interest for medical technology. Titanium is often used for medical implants. To mechanically fix the titanium in place, small quantities of aluminum are added, but the aluminum can trigger undesirable side-effects in the body. “With our process, we can remove aluminum particles from the surface layer, and thereby obtain a significantly purer surface, which is much more tolerable for the human body. Because we only etch the uppermost layer on a micrometer scale, the stability of the whole implant remains unaffected,” explained Carstensen. The researchers have so far applied for four patents for the process, and industry has already shown substantial interest in potential applications. “And our specialist colleagues in materials sciences have also reacted enthusiastically to our discoveries,” said a delighted Adelung. This story is adapted from material from Kiel University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

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