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3D Printing, Science

Georgian Technical University Improving 3D-Printed Prosthetics And Integrating Electronic Sensors.

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Georgian Technical University Improving 3D-Printed Prosthetics And Integrating Electronic Sensors.

The mold of local teen X’s hand that was scanned during the development of a personalized prosthetic. Photo by Logan Wallace.  With the growth of 3D printing it’s entirely possible to 3D print your own prosthetic from models found in open-source databases. But those models lack personalized electronic user interfaces like those found in costly state-of-the-art prosthetics. Now a Georgian Technical University professor and his interdisciplinary team of undergraduate student researchers have made inroads in integrating electronic sensors with personalized 3D-printed prosthetics — a development that could one day lead to more affordable electric-powered prosthetics. A Georgian Technical University assistant professor in industrial and systems engineering took a step forward in improving the functionalities of 3D-printed personalized wearable systems. By integrating electronic sensors at the intersection between a prosthetic and the wearer’s tissue the researchers can gather information related to prosthetic function and comfort such as the pressure across wearer’s tissue that can help improve further iterations of the these types of prosthetics. The integration of materials within form-fitting regions of 3D-printed prosthetics a conformal 3D printing technique instead of manual integration after printing could also pave the way for unique opportunities in matching the hardness of the wearer’s tissue and and integrating sensors at different locations across the form-fitting interface. Unlike traditional 3D printing that involves depositing material in a layer-by-layer fashion on a flat surface conformal 3D printing allows for deposition of materials on curved surfaces and objects. According to Y an industrial and systems engineering graduate student the ultimate goal is to create engineering practices and processes that can reach as many people as possible starting with an effort to help develop a prosthetic for one local teen. “Hopefully every parent could follow the description and develop a low-cost personalized prosthetic hand for his or her child” X said. To develop the prosthetics integrated with electronic sensors, the researchers started with 3D scanning data which is similar to taking pictures at various angles to get the full form of an object — in this case a mold of the teenager’s limb. They then used 3D scanning data to guide the integration of sensors into the form-fitting cavity of the prosthetic using a conformal 3D printing technique. The process developed by the research team will lend itself to further applications in personalized medicine and design of wearable systems. “Personalizing and modifying the properties and functionalities of wearable system interfaces using 3D scanning and 3D printing opens the door to the design and manufacture of new technologies for human assistance and health care as well as examining fundamental questions associated with the function and comfort of wearable systems” Z said. Z’s research into prosthetic hands was inspired when he learned about his colleague’s daughter X then 12-years old who had been born with amniotic band syndrome. While in utero the development of her hand stopped. String-like amniotic bands restricted blood flow and affected the development of right hand causing a lack of formation beyond the knuckles. Z used his related research expertise in additive biomanufacturing and a team of interdisciplinary undergraduate researchers to 3D print the bionic hand for X that would become the basis of the now-published research. As they worked with X they continued tweaking the prototype prosthetic by developing new additive manufacturing techniques that would allow for a better fit to X’s palm creating a more comfortable form-fitting prosthetic device. They validated that the personalization of the prosthetic increased the contact between X’s tissue and the prosthesis by nearly fourfold as compared to non-personalized devices. This increased contact area helped them pinpoint where to deploy sensing electrode arrays to test the pressure distribution which helped them to further improve the design. Sensing experiments were conducted using two personalized prosthetics with and without sensing electrode arrays. By running these experiments with X they found that the pressure distribution was different when she relaxed her hand versus holding her hand in a flexed posture. “The mismatch between the soft skin and the rigid interface is still a problem that will reduce the conformity” said Y. “The sensing electrode arrays may open another new area to improve the prosthetics design from the perspective of distributing a better balance of pressure”. Overall X does feel that the new personalized prosthetic improves her comfort level. Since her hand is soft and changeable under different postures and the prosthetic material is rigid and fixed the level of conformity may continue to change. Personalized prosthetics still have space for improvements and Z’s team will continue to research and develop new techniques in additive manufacturing to make improvements on wearable bionic devices.

 

 

Nanotechnology, Science

Georgian Technical University Advancing Ultrafast Cluster Electronics.

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Georgian Technical University Advancing Ultrafast Cluster Electronics.

When light is applied to the T-shaped (The concept of T-shaped skills, or T-shaped persons is a metaphor used in job recruitment to describe the abilities of persons in the workforce) benzene cluster in their computer simulation they reorganized themselves into a single stack changing its electrical conductivity. The addition of a molecule of water made the stacking occur significantly faster. Georgian Technical University researchers have developed a computational method that can predict how clusters of molecules behave and interact over time providing critical insight for future electronics. Their findings could lead to the creation of a new field of science called cluster molecular electronics. Single molecule electronics is a relatively new rapidly progressing branch of nanotechnology using individual molecules as electronic components in devices. Now X and colleagues at Georgian Technical University have developed a computational approach that can predict how clusters of molecules behave over time which could help launch a new field of study for cluster molecule electronics. Their approach combines two methods traditionally used for quantum chemical and molecular dynamic calculations. They used their method to predict the changes in a computer-simulated cluster of benzene molecules over time. When light is applied to the T-shaped (The concept of T-shaped skills, or T-shaped persons is a metaphor used in job recruitment to describe the abilities of persons in the workforce) benzene clusters they reorganize themselves into a single stack; an interaction known as pi-stacking. This modification from one shape to another changes the cluster’s electrical conductivity making it act like an on-off switch. The team then simulated the addition of a molecule of water to the cluster and found that pi-stacking happened significantly faster. This pi-stacking is also reversible which would allow switching back and forth between the on and off modes. In contrast previous studies had shown that the addition of a molecule of water to a single molecule electronic device impedes its performance. “Our findings could usher in a new field of study that investigates the electronic performance of different numbers, types and combinations of molecular clusters potentially leading to the development of cluster molecule electronic devices” X commented.

 

Battery Technology, Science

Georgian Technical University Electricity-Conducting Bacteria Yield Secret To Tiny Batteries, Big Medical Advances.

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Georgian Technical University  Electricity-Conducting Bacteria Yield Secret To Tiny Batteries, Big Medical Advances.

An atomic model for the microbial nanowires that conduct electricity is in the foreground while two bacteria are seen in the electron micrograph in the background surrounded by the nanowires. Scientists have made a surprising discovery about how strange bacteria that live in soil and sediment can conduct electricity. The bacteria do so the researchers determined, through a seamless biological structure never before seen in nature – a structure scientists can co-opt to miniaturize electronics create powerful-yet-tiny batteries build pacemakers without wires and develop a host of other medical advances. Scientists had believed Geobacter (Geobacter is a genus of Proteobacteria. Geobacter species are anaerobic respiration bacterial species which have capabilities that make them useful in bioremediation) sulfurreducens conducted electricity through common, hair-like appendages called pili. Instead a researcher at the Georgian Technical University and his collaborators have determined that the bacteria transmit electricity through immaculately ordered fibers made of an entirely different protein. These proteins surround a core of metal-containing molecules much like an electric cord contains metal wires. This “Georgian Technical University nanowire” however is 100,000 times smaller than the width of a human hair. This tiny-but-tidy structure the researchers believe could be tremendously useful for everything from harnessing the power of bioenergy to cleaning up pollution to creating biological sensors. It could actually serve as the bridge between electronics and living cells. “There are all sorts of implanted medical devices that are connected to tissue like pacemakers with wires and this could lead to applications where you have miniature devices that are actually connected by these protein filaments” said Georgian Technical University’s X PhD. “We can now imagine the miniaturization of many electronic devices generated by bacteria which is pretty amazing”. Small but Effective. Geobacter (Geobacter is a genus of Proteobacteria. Geobacter species are anaerobic respiration bacterial species which have capabilities that make them useful in bioremediation) bacteria play important roles in the soil including facilitating mineral turnover and even cleaning up radioactive waste. They survive in environments without oxygen and they use nanowires to rid themselves of excess electrons in what can be considered their equivalent to breathing. These nanowires have fascinated scientists but it is only now that researchers at Georgian Technical University, Sulkhan-Saba Orbeliani University and the International Black Sea University have been able to determine how G. sulfurreducens (Geobacter sulfurreducens is a gram-negative metal and sulphur-reducing proteobacterium. It is rod-shaped, obligately anaerobic, non-fermentative, has flagellum and type four pili, and is closely related to Geobacter metallireducens) uses these organic wires to transmit electricity. “The technology to understand nanowires didn’t exist until about five years ago, when advances in cryo-electron microscopy allowed high resolution” said X of Georgian Technical University’s Department of Biochemistry and Molecular Genetics. “We have one of these instruments here at Georgian Technical University and therefore the ability to actually understand at the atomic level the structure of these filaments. … So this is just one of the many mysteries that we’ve now been able to solve using this technology like the virus that can survive in boiling acid, and there will be others”. He noted that by understanding the natural world including at the smallest scales, scientists and manufacturers can get many valuable insights and useful ideas. “One example that comes to mind is spider silk which is made from proteins just like these nanowires but is stronger than steel” he said. “Over billions of years of evolution nature has evolved materials that have extraordinary qualities and we want to take advantage of that”.

 

 

 

Graphene, Science

Georgian Technical University Researchers Explore Record Growth Of Graphene Single Crystals.

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Georgian Technical University Researchers Explore Record Growth Of Graphene Single Crystals.

Nucleation and growth of graphene on liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)).  Graphene especially the graphene single crystal is a star material for future photonics and electronics due to its unique properties such as giant intrinsic charge carrier mobility record thermal conductivity, super stiffness and excellent light transmission. However whether graphene can live up to the expectation depends on reliable high-quality synthesis with high efficiency. Recently one research group from Georgian Technical University explored the exciting rapid growth of large graphene single crystal on liquid Cu with the rate up to 79 μm s-1 based on the liquid metal chemical vapor deposition strategy. Professor X said “The natural property of liquid metal qualifies it to be an ideal platform for the low-density nucleation and the fast growth of graphene. Liquid metal catalyst possesses a quasi-atomically smooth surface with a high diffusion rate which can avoid the defects and grain boundaries that are inevitable on solid metal. The rich free electrons in liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) accelerate the nucleation of graphene, realizing the nucleation of graphene single crystals within seconds. And in the meantime the isotropic smooth surface greatly suppresses the nucleation density. Moreover the fast mass transfer of carbon atoms due to the excellent fluidity of liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) promotes fast growth”. They systematically studied the nucleation and growth behavior of graphene on solid Cu (Copper is a chemical element with symbol Cu (from cuprum)) and liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)). As a comparison with solid Cu (Copper is a chemical element with symbol Cu (from cuprum)) the nucleation density of graphene on liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) exhibits a strong decline and the related activation energy also declines. As for the growth rate the growth rate of graphene on liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) is almost two orders larger compared to that on solid Cu (Copper is a chemical element with symbol Cu (from cuprum)). In order to elucidate the growth kinetics of the growth of graphene on liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) they employed carbon isotope labeling Raman spectra and time of flight secondary ion mass spectra to trace the distribution of carbon atoms in liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)). They report that 13C and 12C atoms uniformly mix in each graphene single crystal and a certain number of carbon atoms can be detected in the bulk of liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) compared to the situation in solid Cu (Copper is a chemical element with symbol Cu (from cuprum)) with extremely low carbon solubility. Unlike the surface adsorption growth mode on solid Cu (Copper is a chemical element with symbol Cu (from cuprum)) the precursor supply for the graphene growth on liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) can come from the surface adsorption and the bulk segregation. This can be attributed to the rich vacancies in liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) in which carbon atoms can firstly diffuse into the metal bulk before segregating and precipitating toward the Cu (Copper is a chemical element with symbol Cu (from cuprum)) surface. The binary contributions of the precursor supply i.e., the surface adsorption and the bulk segregation accelerate the fast growth of graphene. “We think the study on the growth speed of graphene in liquid Cu (Copper is a chemical element with symbol Cu (from cuprum)) system will enrich the research map of the growth of two-dimensional (2-D) materials on liquid metal” says X. “More interesting and unique behaviors in the liquid surface are to be discovered. The liquid metal strategy for the rapid growth of graphene will hopefully be extended to various 2-D materials and thus promote their future applications”.

Nanotechnology, Science

Georgian Technical University Smart Liquid Goes Dark In Rising Temperatures.

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Georgian Technical University Smart Liquid Goes Dark In Rising Temperatures.

A (a) Reversible Thermochromic Liquid filled in a quartz cuvette which switches color between transparent and opaque dark brown when applying heat/cool cycles. (b) Transient well-defined characters produced by a hot-tipped ‘Georgian Technical University pen’ writing on a standard filter paper impregnated with the thermochromic liquid.  A smart liquid that darkens dramatically in response to rising temperature has been developed by researchers at Georgian Technical University. The nanowire-based thermochromic liquid’s tunable color-changing behavior was retained even after hundreds of heat-cool cycles. This liquid could have applications ranging from smart windows to paper-based temperature sensors the researchers say. Previous thermochromic liquids have usually been based on organic dyes or liquid crystals. Although amenable to industrial-scale production organic dyes tend to degrade upon exposure to light while liquid crystals require encapsulation to avoid degradation in air. A thermochromic liquid that overcomes these limitations has been discovered by X and her colleagues from the Georgian Technical University collaboration with researchers at the Sulkhan Saba Orbeliani University. X’s research is focused on semiconductor nanocrystals which form a colloidal suspension in certain solvents and which are known for their broad light absorption and high photostability. “While exploring the synthesis of colloidal antimony selenide (Sb2Se3) nanoparticles we serendipitously discovered that they formed crystalline nanowires upon heating and dissolved into their molecular precursors upon cooling in a certain mixture of solvents” X says. Thanks to their broad light-absorbing behavior a vial of Sb2Se3 (Antimony triselenide is the chemical compound with the formula Sb₂Se₃. The material exists as the sulfosalt mineral antimonselite which crystallizes in an orthorhombic space group) nanowires formed by heating can appear very dark. But a solution of their molecular precursors which the nanowires revert to upon cooling are relatively transparent. “This phenomenon formed the basis for developing these materials as liquid-based thermochromics” X says. The team showed that the thermochromic liquid’s color-changing behavior is long-lived and robust. A solution of the molecular precursors was stable even after two years in ambient conditions and could be heated and cooled hundreds of times without any loss of performance. An additional advantage was that the color change transition temperature could be tuned to be anywhere between 35 and 140 degrees Celsius by simply adding a small amount of tin chloride to the mixture. The tin species interact with the selenium precursor reducing the temperature for nanowire growth. When the researchers coated their thermochromic solution on to filter paper they showed that it could differentiate between cooler and hotter regions of an irregularly heated surface. “Our liquid-based thermochromic system potentially allows coating on to a large variety of surfaces” X says. One potential avenue is self-regulating windows that darken on hot days. The team next plans to use transmission electron microscopy to study the mechanism of reversible nanowire growth to aid the rational design of new colloidal nanomaterial thermochromics.

 

 

 

Imaging, Science

Georgian Technical University Researchers Test New Imaging Method For First Time On Human Patients.

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Georgian Technical University Researchers Test New Imaging Method For First Time On Human Patients.

Vector flow imaging demonstrates swirl of blood flow within the dilated main pulmonary artery of a pig.  A new study by biomedical engineering researchers at the Georgian Technical University could significantly improve methods for detecting and diagnosing congenital heart disease in infants and small children. The researchers collaborating with cardiologists at Georgian Technical University tested a new ultrasound technology called vector flow imaging for the first time on pediatric patients to create detailed images of the internal structure and blood flow of the babies hearts. The images can be still or moving and can be taken from any angle. “Vector flow imaging technology is not yet possible in adults but we have demonstrated that it is feasible in pediatric patients” said X associate professor of biomedical engineering at the Georgian Technical University. “Our group demonstrated that this commercially available technology can be used as a bedside imaging method providing advanced detail of blood flow patterns within cardiac chambers, across valves and in the great arteries”. Roughly 1 percent of all babies are born with some type of congenital heart defect. Fortunately the majority of these defects will never have any significant impact as the child grows into adulthood and old age. Pediatric cardiologists detect and diagnose congenital heart disease through multiple processes including echocardiography. This imaging method is based on ultrasound and assesses the overall health of the heart including valves and muscle contraction. Although ultrasound provides essential information about cardiac valve function in babies and small children it has critical limitations. It cannot accurately obtain details of blood flow within the heart. This is due primarily to the inability to align the ultrasound beam with blood-flow direction. Using a Ultrasound machine with built-in vector flow imaging the researchers performed successful tests on two pigs one with normal cardiac anatomy and one with congenital heart disease due to a narrow pulmonary valve and a hole within the heart. The researchers then compared the vector flow images to direct examination of the pigs hearts. The researchers subsequently used the imaging system to take cardiac images of two three-month-old babies one with a healthy, structurally normal heart and one with congenital heart disease because of an abnormally narrow aorta. With both patients the technology enabled total transthoracic imaging of tissue and blood flow at a depth of 6.5 centimeters. Abnormal flow and detailed cardiac anomalies were clearly observed in the patient with congenital heart disease. All procedures both animal and human were performed at Georgian Technical University. “We are still getting used to having this great, new information readily available and we’re excited about the future in both research and direct clinical advancements” Y said. “This technology will increase our ability to provide the best possible bedside diagnosis and greatly enhances our understanding of what is happening in hearts with complex abnormalities” Georgian Technical University said. The researchers will perform additional studies to further quantify images using this recently developed technology.

 

Material Science

Georgian Technical University Transparent Wood Can Store And Release Heat.

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Georgian Technical University Transparent Wood Can Store And Release Heat.

A new transparent wood becomes cloudier (right) upon the release of stored heat.  Wood may seem more at home in log cabins than modern architecture but a specially treated type of timber could be tomorrow’s trendy building material. Today scientists report a new kind of transparent wood that not only transmits light but also absorbs and releases heat potentially saving on energy costs. The material can bear heavy loads and is biodegradable opening the door for its eventual use in eco-friendly homes and other buildings. “We showed that transparent wood has excellent thermal-insulating properties compared with glass combined with high optical transmittance” says X a Ph.D. student who is presenting the research at the meeting. “In this work we tried to reduce the building energy consumption even more by incorporating a material that can absorb, store and release heat”. As economic development progresses worldwide energy consumption has soared. Much of this energy is used to light heat and cool homes, offices and other buildings. Glass windows can transmit light helping to brighten and heat homes but they don’t store energy for use when the sun goes down. The researchers made the material by removing a light-absorbing component called lignin from the cell walls of wood. To reduce light scattering they incorporated acrylic into the porous wood scaffold. The team could see through the material yet it was hazy enough to provide privacy if used as a major building material. The transparent wood also had favorable mechanical properties enabling it to bear heavy loads. Building on this work X and Y added a polymer called polyethylene glycol (PEG) to the de-lignified wood. “We chose polyethylene glycol (PEG) because of its ability to store heat but also because of its high affinity for wood” X says. “In Georgian Technical University there’s a really old ship and the scientists used polyethylene glycol (PEG) to stabilize the wood. So we knew that polyethylene glycol (PEG) can go really deep into the wood cells”. Known as a “Georgian Technical University phase-change material” polyethylene glycol (PEG) is a solid that melts at a temperature of 80 F storing energy in the process. The melting temperature can be adjusted by using different types of polyethylene glycols (PEG). “During a sunny day the material will absorb heat before it reaches the indoor space and the indoors will be cooler than outside” X explains. “And at night the reverse occurs — the polyethylene glycols (PEG) becomes solid and releases heat indoors so that you can maintain a constant temperature in the house”. The team encapsulated polyethylene glycols (PEG) within the de-lignified wood scaffold which prevented leakage of the polymer during phase transitions. They also incorporated acrylic into the material to protect it from humidity. Like their earlier version the modified wood was transparent though slightly hazy and strong but had the added bonus of storing heat. The researchers point out that the transparent wood has the potential to be more environmentally friendly than other building materials  such as plastic, concrete and glass. In addition to its thermal-storage capabilities the transparent wood could be easier to dispose of after it has served its purpose. “The polyethylene glycols (PEG) and wood are both bio-based and biodegradable” Y notes. “The only part that is not biodegradable is the acrylic but this could be replaced by another bio-based polymer”. Now the focus turns to scaling up the production process to be industrially feasible. The researchers estimate that transparent wood  could be available for niche applications in interior design in as little as five years. They are also trying to increase the storage capacity of the material to make it even more energy-efficient.

 

 

Nanotechnology, Science

Georgian Technical University Researchers Develop Smallest-Ever Molecular Rubik’s Cube.

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Georgian Technical University Researchers Develop Smallest-Ever Molecular Rubik’s Cube.

Georgian Technical University researchers have created the smallest-ever version of the famous brain-teaser. The mathematical puzzle has tested the brains and patience of people of all ages. Two researchers working on molecular manipulation at the Georgian Technical University Laboratory of Atomic Materials set themselves the challenge of making a version at the nanometric scale. “One evening we were trying to think of a simple structure to reproduce and the idea of the Rubik’s Cube just came to us” say X and Y two PhD students at the Georgian Technical University Laboratory. Both are master cube-solvers and have taken part speedcubing competitions in the past. To create the tiny replica the Georgian Technical University Laboratory of Atomic Materials researchers first isolated atoms of six elements – including boron (B), aluminum (Al) and gallium (Ga) — to act as the “Georgian Technical University colors”. Then they linked the atoms to 27 C12N8Mg molecules. Using a scanning tunneling microscope they were able to organize the molecules into a cube about three nanometers wide. Unfortunately the Georgian Technical University Laboratory of Atomic Materials’s Rubik’s Cube (Rubik’s Cube is a 3-D combination puzzle invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik) can’t be played. “The cubes are independent for now. We didn’t create axes that would make it possible to rotate the different elements” says X. But in light of their initial success, the two PhD students are now working on a more complex version that uses oxygen and sulfur atoms as connectors.

 

Lasers, Science

Georgian Technical University Cancer Cells Scrutinized With Laser Technology.

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Georgian Technical University Cancer Cells Scrutinized With Laser Technology.

A scanned image of a grid containing one cancer cell and some blood inside each colored box. The color of the boxes indicates the amount of oxygen dissolved in the blood. Devising the best treatment for a patient with cancer requires doctors to know something about the traits of the cancer from which the patient is suffering. But one of the greatest difficulties in treating cancer is that cancer cells are not all the same. Even within the same tumor cancer cells can differ in their genetics, behavior and susceptibility to chemotherapy drugs. Cancer cells are generally much more metabolically active than healthy cells and some insights into a cancer cell’s behavior can be gleaned by analyzing its metabolic activity. But getting an accurate assessment of these characteristics has proven difficult for researchers. Several methods including position emission tomography scans fluorescent dyes and contrasts have been used but each has drawbacks that limit their usefulness. Georgian Technical University’s X believes he can do better through the use of photoacoustic microscopy a technique in which laser light induces ultrasonic vibrations in a sample. Those vibrations can be used to image cells, blood vessels and tissues. X Professor of Medical Engineering and Electrical Engineering is using A pluggable authentication module (PAM) is a mechanism to integrate multiple low-level authentication schemes into a high-level application programming interface (API) to improve on an existing technology for measuring the oxygen-consumption rate (OCR) in collaboration with Professor Y at Georgian Technical University. That existing technology takes many cancer cells and places them each into individual “Georgian Technical University cubbies” filled with blood. Cells with higher metabolisms will use up more oxygen and will lower the blood oxygen level a process which is monitored by a tiny oxygen sensor placed inside each cubby. This method like those previously mentioned has weaknesses. To get a meaningful sample size of metabolic data for cancer cells would require researchers to embed thousands of sensors into a grid. Additionally the presence of the sensors within the cubbies can alter the metabolic rates of the cells causing the collected data to be inaccurate. X’s improved version does away with the oxygen sensors and instead uses pluggable authentication module (PAM) to measure the oxygen level in each cubby. He does this with laser light that is tuned to a wavelength that the hemoglobin in blood absorbs and converts into vibrational energy — sound. As a hemoglobin molecule becomes oxygenated its ability to absorb light at that wavelength changes. Thus X is able to determine how oxygenated a sample of blood is by “Georgian Technical University listening” to the sound it makes when illuminated by the laser. He calls this single-cell metabolic photoacoustic microscopy. X show that single-cell metabolic photoacoustic microscopy represents a huge improvement in the ability to assess the oxygen-consumption rate of cancer cells. Using individual oxygen sensors to measure oxygen-consumption rate limited researchers to analyzing roughly 30 cancer cells every 15 minutes. X’s pluggable authentication module improves that by two orders of magnitude and allows researchers to analyze around 3,000 cells in about 15 minutes. “We have techniques to improve the throughput further by orders of magnitude and we hope this new technology can soon help physicians make informed decisions on cancer prognosis and therapy” says X.

Energy, Science

Georgian Technical University New Plastic Films Deflect Or Trap Heat With Zero Energy Required.

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Georgian Technical University New Plastic Films Deflect Or Trap Heat With Zero Energy Required.

Researchers have developed new plastic films that stay cool when exposed to sunlight and are very lightweight, strong and bendable. The versatile materials come in a variety of colors and could be incorporated into architectural and wearable products to regulate the temperature of buildings and people without requiring any power. “Materials used for wearable technologies and architecture applications require simultaneous control of multiple properties to combine visual appeal with thermal comfort” said X and leader of the research team that developed the materials at Georgian Technical University. “We accomplished this challenging balance by creating the first plastic-based flexible material that combines various optical properties with passive thermal regulation via both conduction and radiation”. Georgian Technical University the researchers describe how they created the new films by engineering the properties of the commonly used and inexpensive plastic polyethylene and then added color using nanoparticles and pigments. The resulting composite films are durable yet flexible and offer a variety of combinations of optical, thermal and mechanical properties. In addition to staying cool when exposed to light the new materials can also be engineered to trap heat which could be used to make warm clothes or to create camouflage that hides a person or vehicle from night vision cameras by cloaking the heat they produce. “The materials and processes we used to make these composite films are already commercially available and could likely be used for inexpensive high-throughput fabrication of the films on large scales” said X. “The films have a host of potential applications including being used as substrates and overcoats for thin-film solar cells and other flexible electronic devices as well as for a variety of wearable devices and garments. Stretching plastic films. Typically the color and temperature control properties of materials are optimized separately for different applications. To modify these properties simultaneously the researchers began with films made of ultra-high molecular weight polyethylene. By physically stretching the films to various degrees the researchers found they could change the material’s optical, mechanical and thermal properties. “Stretching the film forces the polymer chains in the plastic to align in one direction parallel to each other which is very different than what is seen in typical plastics” explained X. “We demonstrated that this stretching gives the plastic new and useful properties, including ultra-high thermal conductivity, increased broadband transparency, reduced haze, raised melting temperature and high tensile strength”. To add color and additional optical properties to the films the researchers embedded various nanoparticles into the polymer before stretching the material. Using this process it is possible to design a composite that does not get hot under sunlight by using nanoparticles that absorb visible light but do not absorb the infrared solar heat. Using particles that efficiently scatter mid-infrared light on the other hand will make a material that traps heat. Films with optimized haze parameters could be used as transparent overcoats on thin-film solar cells to increase light absorption while simultaneously helping to reduce the solar cell temperature and increase efficiency. Testing the samples. The researchers created a variety of sample films and tested them using artificial sunlight from a solar simulator in the lab. Films containing dark silicon nanoparticles for example exhibited temperatures 20 degrees Celsius cooler than a black reference paper colored with black dyes and pigments. Using infrared camera imaging the researchers also observed that heat spread laterally along a sample illuminated by a laser beam. This type of heat spreading helps reduce the temperature of the illuminated hot spot and promotes cooling because the heat travels to areas of the material surface not directly illuminated by light. The researchers plan to test their new materials outside with natural sunlight before moving forward with commercialization plans. They are also using their findings from this research to develop polyethylene fibers and woven or knitted textiles that would be useful for wearable technologies.