Archive for bone regeneration
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Lot’s of good stories here:
The Indian Prime Minister was forced to cancel his planned visit to Japan this month after the Japanese government dissolved the lower house of parliament and announced early elections. An important trade pact in respect of rare earth materials was proposed to be signed during the visit. Fortunately, the cancellation of the Indian Prime Minister’s visit has not come in the way of the realisation of this pact. On Nov. 16, a trade pact allowing the import of 4,100 tons of rare earth elements material (amounts to roughly 10 to 15 percent of Japan’s peak annual demand) from India has been signed by the two countries. India is known to be the second largest producer of REEs. According to one estimate made in 2010, China produced 1.3 lakh tons of REEs while India’s output was 2,700 tons. India, in spite of being a small player in comparison with China, has been in the business of REEs since the 1950s when Indian Rare Earths Ltd. was established. The recent agreement between Japan and India on REEs could also be viewed as a continuation of their existing relationship in the field of REEs. Japan has already made investments in this regard in India. The most interesting aspect of India and Japan coming together is that they are also proposing to engage with other states where REEs are available for excavation. India and Japan want to develop a joint venture in third countries, particularly in underdeveloped states, such as Afghanistan and Kazakhstan.
(R&D News) Providing protection against impacts from bullets and other high-speed projectiles is more than just a matter of brute strength. While traditional shields have been made of bulky materials such as steel, newer body armor made of lightweight material such as Kevlar has shown that thickness and weight are not necessary for absorbing the energy of impacts. Now, a new study by researchers at MIT and Rice University has shown that even lighter materials may be capable of doing the job just as effectively. The key is to use composites made of two or more materials whose stiffness and flexibility are structured in very specific ways-such as in alternating layers just a few nanometers thick. The research team produced miniature high-speed projectiles and measured the effects they had on the impact-absorbing material. The team developed a self-assembling polymer with a layer-cake structure: rubbery layers, which provide resilience, alternating with glassy layers, which provide strength. They then developed a method for shooting glass beads at the material at high speed by using a laser pulse to rapidly evaporate a layer of material just below its surface. Though the beads were tiny-just millionths of a meter in diameter-they were still hundreds of times larger than the layers of the polymer they impacted: big enough to simulate impacts by larger objects, such as bullets, but small enough so the effects of the impacts could be studied in detail using an electron microscope.
Although widespread rebuilding in the hard-hit New York metro region from Super Storm Sandy has not yet begun, New Jersey Institute of Technology Assistant Professor Mohamed Mahgoub says when the hammers start swinging, it’s time to look at autoclaved aerated concrete. The material, best known as AAC, has been heralded as the building material of the new millennium. It’s a lightweight, easily-crafted manufactured stone, strong enough to withstand earthquakes and hurricanes when reinforced with steel. The material is used widely worldwide, says Mahgoub. Mahgoub is also the coordinator of the NJIT Concrete Industry Management program, which is only one of a select few programs of its kind across the United States. This semester CIM students are testing and analyzing AAC. “It is an environmentally-friendly solution for future building problems and it is also an extremely efficient, specialty fabrication material,” he says. “Cuts can easily be factory controlled. AAC is available throughout the U.S. and Canada. There is currently one U.S. manufacturer in Florida with plans to open another manufacturing operation in New Jersey.” AAC is workable and lightweight like wood. It can provide outstanding thermal insulation, is resistant to fire, termites and decay. A concrete product, AAC consists of finely ground sand, cement, quick lime, gypsum, aluminum and water. “Most sand is too coarse for the manufacturing of AAC,” notes Mahgoub.
(BBC) A concrete that contains limestone-producing bacteria, which are activated by corrosive rainwater working its way into the structure, could potentially increase the service life of the concrete—with considerable cost savings as a result. The work is taking place at Delft Technical University, Netherlands. It is the brainchild of microbiologist Henk Jonkers and concrete technologist Eric Schlangen. If all goes well, Jonkers says they could start the process of commercializing the system in 2-3 years. Bacterial spores and the nutrients they will need to feed on are added as granules into the concrete mix. But water is the missing ingredient required for the microbes to grow. So the spores remain dormant until rainwater works its way into the cracks and activates them. The harmless bacteria, belonging to the Bacillus genus, then feed on the nutrients to produce limestone. The bacterial food incorporated into the healing agent is calcium lactate—a component of milk. The microbes used in the granules are able to tolerate the highly alkaline environment of the concrete. ”In the lab we have been able to show healing of cracks with a width of 0.5 mm, 2-3 times higher than the norms state,” Jonkers explained. ”Now we are upscaling. We have to produce the self-healing agent in huge quantities and we are starting to do outdoor tests, looking at different constructions, different types of concrete to see if this concept really works in practice.” The main challenge is to ensure the healing agent is robust enough to survive the mixing process. But, in order to do so, says Jonkers, “we have to apply a coating to the particles, which is very expensive”. The team is currently trying to reduce the cost this adds to the process. But he expects an improved system to be ready in about six months. The outdoor tests should begin after this; the team is already talking to several construction firms that could provide help. The concrete will then have to be monitored for a minimum of two years to see how it behaves in this real-world setting.
Researchers have figured out how to recreate the bright, beautiful colors of butterfly wings, as well as their ability to strongly repel water. The colors of a butterfly’s wings are the result of an unusual trait-the way they reflect light is fundamentally different from how color works most of the time. A team of researchers at the University of Pennsylvania has found a way to generate this kind of “structural color.” Shu Yang, associate professor in the department of materials science and engineering, led the research. She and colleagues report their findings in the journal Advanced Functional Materials. The two qualities-structural color and superhydrophobicity-are related by structures. Structural color is the result of periodic patterns, while superhydrophobicity is the result of surface roughness. While trying to combine these traits, engineers have to go through complicated, multi-step processes, first to create color-providing 3D structures out of a polymer, followed by additional steps to make them rough in the nanoscale.
(GigaOm) A Chicago startup is ready to commercialize an electric motor that presents an alternative to the conventional motors that require the use of rare earth materials. HEVT hopes to raise money to scale up production. Political battles over rare earth materials - which are crucial for many energy components, like lighting, batteries and motors - have spawned efforts to create technologies free of these materials. A startup called HEVT (or Hybrid Electric Vehicle Technologies), which recently won the national Cleantech competition, has developed a rare earth-free electrical motor and is looking to deliver its technology to market first in electric bicycles. The Chicago-based company has engineered a high-performance “switched reluctance motor” and says it has solved the noise and vibration problem that has crippled efforts in the past to commercialize it, according to Heidi Lubin, CEO of HEVT. The motor presents an alternative to conventional induction and magnet motors, which require rare earth elements that can be hard to secure. HEVT is part of a team, led by the University of Texas at Dallas, to design a switch reluctance motor with nearly $3 million from the ARPA-E program. Rare earth mining and processing also can be environmentally unfriendly. HEVT was founded in 2005 within the Illinois Institute of Technology to target electric hybrids and plug-in electric cars and trucks. But that market is hard to crack. The pace of electric car adoption hasn’t taken off as quickly as some proponents would’ve liked to see, and some battery makers in particular have had trouble meeting their sales projections. So HEVT wants to tackle the more established electric bicycle market first.
For work toward a safer approach to treating cancer, electrical engineering PhD student Inanc Ortac from the University of California, San Diego has won first prize in the graduate student category at the 2012 Collegiate Inventors Competition. Ortac’s winning entry offers a new approach for delivering cancer drugs just to the areas where the drugs are needed. This kind of targeted drug delivery minimizes collateral damage to non-cancerous cells. “With our nano-wiffle-ball technology, we expect that the lethal side effects to chemotherapy can be greatly reduced, the efficacy of the therapy can be increased, and the quality of life of patients can be improved,” said Ortac. The proposed nano-wiffle-ball approach for the treatment of solid tumors and metastatic cancers would involve multiple steps. First, the nano-wiffle-balls, which are nano-scale capsules made of silica, are filled with foreign enzymes. The nano-wiffle-balls encapsulate the enzymes and effectively hide them from the body’s immune system. Trillions of nano-wiffle balls loaded with foreign enzymes would then travel through the blood stream and accumulate at the cancer sites. Next, a doctor would administer a non-toxic, inactive drug precursor (prodrug) that enters these nanocapsules reacts with the enzyme cargo. These reactions activate the prodrug, turning it into an active cancer-fighting drug. Preclinical trials for a number of cancer types including colorectal cancer, pancreatic cancer, acute lymphoblastic leukemia, and metastatic breast cancer are under way and clinical studies will follow, according to Ortac.
Coating a bone graft with an inorganic compound found in bones and teeth may significantly increase the likelihood of a successful implant, new research from Penn State shows. Natural bone grafts need to be sterilized and processed with chemicals and radiation before implantation into the body to make sure disease isn’t transmitted by the graft. Human bones have a rough surface. However, once a graft is sterilized the surface changes and doesn’t work as well at stimulating bone formation in the body. Researchers developed a way to create a rough surface on bone grafts that is similar in texture to the surface of an untreated bone that promotes healing. By coating a bone with hydroxyapatite using physical vapor deposition, they could closely mimic the rough surface of an untreated bone. To find the optimum thickness of hydroxyapatite, the group sterilized the graft samples. After sterilization, physical vapor deposition layered different amounts of hydroxyapatite on the grafts.
The University of the Basque Country (Universidad del País Vasco) reports that one of its Ph.D. students has developed a new porous, biodegradable nanocompound support for the regeneration of bone tissue. According to UPV, Beatriz Olalde, in her doctoral thesis, reported on her approach that combines polylactic acid, hydroxyapatite and carbon nanotubes to form a material that could be used instead of bone grafts. Her material interacts chemically and electrically with bone cells and adjoining tissue to speed bone replacement and recovery.
Each of the components in Olalde’s foam-like material plays a specific role. The polylactic acid forms a basic biodegradable scaffold. Hydroxyapatite – a benign, bone-like bioceramic substance that is very compatible with tissues – is added attract cell growth and provide a source of calcium. The CNTs are added to provide strength. The CNTs also provide a material that reacts with an external electric field in a way that stimulates cell growth.
The desire for materials like Olalde’s (alloplastic grafts) stems from problems the medical profession faces when, due to events like large scale physical trauma or tumor removal, a patient loses a significant section of bone. Bone has the ability to regenerate itself to a large extent, but that requires time and support for the injured area.
Typically, bone grafts have been used either from the patient (an autograft), a living donor or a cadaver (allografts). But often a patient isn’t capable of providing the graft and donated bone raises complications due to tissue rejection issues, contamination, etc.
According to Olalde, trials involving both in vitro and in vivo experiments have shown satisfactory results. She says the foam displayed good mechanical properties and bone support. In in vivo trials, bone growth was observed after three weeks, and after 16 weeks this new bone showed mechanical, histomorphometric and densitometric properties similar to those of intact, healthy bone tissue.
Olalde has published before about polylactic acid and carbon nanotubes, and has collaborated with the University of Aberdeen, Scotland, and the Institute of Biomechanics of Valencia (IBV). She was awarded her Ph.D. and is currently working as a researcher in the Department of Biomaterials and Nanotechnologies Unit Tecnalia Health.
Researchers at Fraunhofer’s Institute for Laser Technology say they are getting excellent results from a bone replacement system that uses a paste of polyactide (PLA) and tricalcium phosphate that is melted by a fine laser to build up layers of material that can provide a strong and precise fit.
This new approach was developed under the aegis of federal ministry “Resobone” project in Germany.
Researchers say the laser-treated paste develops precise microchannels in the PLA, creating a lattice structure which the adjacent bones can grow into. “Its precision fit and perfect porous structure, combined with the new biomaterial, promise a total bone reconstruction that was hitherto impossible to achieve,” says Ralf Smeets of the University Medical Center of Aachen.
Both PLA and TCP are tolerated well by the body. Many consumers have unknowingly run into PLA, the major component of biodegradable packaging material and clear disposable cups that are becoming commonplace. While the PLA provides the framework, the TCP resides in more or less a granular form in it and acts as a stimulus for bone growth. The body can catabolize both substances as natural bone grows through the lattice.
Fraunhofer says the PLA/TCP Resobone system isn’t really suitable for bones that experience high stress, such as in limbs or joints. Instead, it is ideal for certain low-stress bony areas such as cranial, facial and maxillary bones. For example, a five-centimeter large replacement piece of cranium can be completed in an overnight process that uses data from CT imaging to guide a thin laser beam to melt the PLA/TCP mix layer by layer. The precise, customize-sized implants that results from this “Selective Laser Melting” process can be as thin as 80 micrometers and as large as 25 square centimeters.
Fraunhofer gives much of the credit for developing the manufacturing process to its Institute for Laser Technology in Aachen.
“No custom-fit, degradable implants ever existed before now. During the operation, the surgeon had to cut TCP cubes, or the patient‘s own previously removed bone material, to size and insert it into the fissure,” explains Simon Höges, project manager at ILT. “We have achieved our project goal: a closed process chain to produce individual bony implants from degradable materials.
Apropos to the new MS&T symposium on materials and the effects of electric and magnetic fields, I received a notice that there will be a paper presented tomorrow (March 17) at the annual meeting of the American Physical Society the explores possible routes for improving bone growth, grafts and implants, and looks at the role these fields could play. Yizhi Meng of Stony Brook University and her colleagues have been studying the very early stages of bone formation. Here is the abstract to her paper:
The induction of bone formation to an intentional orientation is a potentially viable clinical treatment for bone regeneration. Among the many chemical and physical factors, electric and magnetic fields are an essential way to regulate the behavior of cells and matrix fibers. The aims of this study are to investigate the effects of electric and magnetic fields on protein self-organization and osteoblast biomineralization on polymer surfaces in vitro. To this end, we use atomic force microscopy to characterize the morphology of protein fiber and ECM by cells. The mechanical property of protein fibers was investigated by shear modulation force microscopy. The late-stage of mineralization was characterized by scanning electron microscopy and grazing incident x-ray diffraction. The primary data indicated that the magnetic field could enhance the biomineralization of osteoblast.
Meng is actually presenting a series of papers at the meeting regarding bone growth, formation of calcium phosphate and biomineralization.
Lehigh University professor Himanshu Jain discusses the school’s work to lead an international effort to develop biocompatible, dually porous glass that helps damaged human bone to regenerate. Jain, who teaches in the Department of Materials Science and Engineering, was the subject of another post we did about a week ago concerning a project to encourage more African-Americans to adopt science and engineering careers.