Showing Spotlights 449 - 456 of 530 in category All (newest first):
Nature is truly a brilliant nano engineer and has been so for billions of years. There is an abundance of 'smart' biological materials with hierarchical nanostructures - built from proteins - that are capable of adapting to new tasks, are self-healing, and can self-assemble autonomously simply out of a solution of building blocks. The performance and capability of these natural materials is something engineers can only dream of today. But by unlocking nature's secrets tiny step by tiny step, one day we will be able to not only duplicate but surpass the performance of natural materials. Only in recent years have scientists begun to understand the underlying principles and mechanisms of these materials - Why is spider silk stronger than steel? Why can cells be stretched reversibly several times of their original length? What kinds of molecular flaws lead to malfunctions in cells and tissues, as it occurs in Alzheimer's, rapid ageing disease progeria or muscle dystrophies, diseases in which the cell or tissue fails mechanically? Scientists at MIT have, for the first time, revealed the fundamental fracture and deformation mechanisms of biological protein materials, clarifying some long-standing issues about the deformation behavior of cells and Alzheimer's pathogens. The researchers report that the fracture mechanisms of two abundant nanoscopic building blocks of many proteins and protein materials exhibit two distinct fracture modes, depending on the speed of deformation. This is a surprising observation with far-reaching implications for the development of novel self-assembled protein materials and possibly the cure of certain genetic diseases
Oct 10th, 2007
There is a huge demand for medical implants for almost every body part you can think of. As we have reported here before, the market for medical implant devices in the U.S. alone is estimated to be $23 billion per year and it is expected to grow by about 10% annually for the next few years. Implantable cardioverter defibrillators, cardiac resynchronization therapy devices, pacemakers, tissue and spinal orthopedic implants, hip replacements, phakic intraocular lenses and cosmetic implants will be among the top sellers. Current medical implants, such as orthopedic implants and heart valves, are made of titanium and stainless steel alloys, primarily because they are biocompatible. Unfortunately, in many cases these metal alloys with a life span of 10-15 years may wear out within the lifetime of the patient. With recent advances in industrial synthesis of diamond and diamond-like carbon film bringing prices down significantly, researchers are increasingly experimenting with diamond coatings for medical implants. On the upside, the wear resistance of diamond is dramatically superior to titanium and stainless steel. On the downside, because it attracts coagulating proteins, its blood clotting response is slightly worse than these materials and the possibility has been raised that nanostructured surface features of diamond might abrade tissue. That's not something you necessarily want to have in your artificial knee or hip joints (although some of the currently used implant materials cause problems as well). Researchers have now run simulations that show that thin layers of ice could persist on specially treated diamond coatings at temperatures well above body temperature. The soft and hydrophilic ice multilayers might enable diamond-coated medical devices that reduce abrasion and are highly resistant to protein absorption.
Sep 18th, 2007
You might have come across the acronym NBIC, which stands for Nanotechnology, Biotechnology, Information technology and new technologies based on Cognitive science. Initially introduced in the U.S. National Science Foundation's 'Converging Technologies for Improving Human Performance' report this acronym is often used to describe the basic idea that scientific and technological innovation can be stimulated through the convergence of two, three, or all four fields. At its most radical (and most controversial), proponents of convergence suggest that nanotechnologies will promote the unification of most branches of science and technology, based on the unity of nature at the nanoscale, including cognitive sciences. We'll keep you posted on this over the next few decades and see how it all works out. For the time being, though, it would be nice to be able to report on something more hands-on and - dare I write it - even practical. As it happens, scientists at the University of Toronto have done exactly that. They have demonstrated, for what appears to be the first time, the convergence of nanotechnology, microtechnology, microfluidics, photonics, signal processing, and proteomics to build a medical device that could lead to the development of fast, portable point-of-care diagnostics for infectious disease (IDs) such as HIV, SARS and many others.
Aug 31st, 2007
In the medical field there is a huge demand for tissue regeneration technologies, which covers a wide range of potential applications in such areas as cartilage, vascular, bladder and neural regeneration. Just consider the need for bone and dental implants: Each year, almost 500,000 patients receive hip implants worldwide, about the same number need bone reconstruction due to injuries or congenital defects and 16 million Americans loose teeth and may require dental implants. The market for medical implant devices in the U.S. alone is estimated to be $23 billion per year and it is expected to grow by about 10% annually for the next few years. Unfortunately, medical implant devices have been associated with a variety of adverse reactions, including inflammation and fibrosis. It has been suggested that poor tissue integration is responsible for loosening of implants and mechanical damage to the surrounding host tissues. Based on an expanding body of biomedical nanotechnology research work, there is a growing consensus among scientists that nanostructured implant materials may have many potential advantages over existing, conventional ones. The key, as indicated in a number of findings, seems to be that physical properties of materials, especially with regard to their surface's nanostructure, affect cell attachment and eventually the tissue response to the implant. Although nanotopography mediated cell responses have been shown in previous work, the mechanism of these responses is mostly undetermined. New research has now been conducted to determine the influence of nanopore size on cellular responses. Interestingly, these studies have revealed that larger nanopores (200 nm) trigger DNA replication and cell proliferation via various signal transduction pathways.
Aug 28th, 2007
Vaccination has resulted in the eradication of smallpox and control of measles, rubella, tetanus, diphtheria, and other infectious diseases in many areas of the world (at least where vaccines are available and affordable; providing vaccines to many parts of the developing world still is one of the basic medical needs that is far from being met). The basic idea of vaccination (the word comes from the Latin vacca - cow - because the first vaccine was derived from a virus affecting cows) is to inject weakened or killed forms of pathogens such as bacteria or viruses into the body in order for the immune system to develop antibodies against them; if the same types of microorganisms enter the body again, they will be destroyed by the antibodies. About 25 years ago, the basic idea of vaccination gave rise to bactofection - the technique of using bacteria as non-viral gene carriers into target cells. The DNA cargo is transported inside the bacteria and, once it arrives at the target location, the bacteria is broken up in order to release the therapeutic gene or protein. A novel technique takes advantage of the invasive properties of bacteria for delivery of nanoparticles into cells. Here, the gene or cargo is not carried inside the bacteria, but rather remains on the surface conjugated to nanoparticles. Consequently, this approach does not require bacterial disruption for delivery, or any genetic engineering of the bacteria for different cargo.
Aug 14th, 2007
The question if certain engineered nanoparticles are toxic, and if yes to what degree, is still one of the major issues that hasn't been properly answered yet. Most studies in the literature thus far have focused on the environmental aspects of nanoparticle toxicity, and these studies have been conducted primarily on industrial or natural/incidental nanoparticles. However, engineered nanoparticles are at the forefront of the rapidly developing field of nanomedicine; and here they are deliberately injected into the body to perform a specific medical application: fluorescent agents for imaging; drug delivery vehicles; or therapeutic agents for the destruction of cancer cells (for instance in thermolysis); just to name a few. A brand new review article provides the first comprehensive summary of the properties of engineered nanoparticles which determine their interaction with components of the immune system. It concludes that nanoparticle-based therapeutics are no more intrinsically immunotoxic than traditional pharmaceuticals, such as biotechnology-derived or small molecules. Moreover, incorporation of traditional drugs into nanotechnology formulations frequently results in a decrease in immunotoxicity compared to the native drug. Although many questions still require thorough investigation, the available data suggest that nanoparticles can be engineered to become the next generation of biocompatible drug delivery platforms.
Aug 2nd, 2007
Recent developments in spectroscopic techniques allow highly sensitive image detection both in vitro and in vivo on the individual cell level. These methods depend on nanometer-size particles as detection probes. One class of such particles, so-called nanocrystals or quantum dots (qdots), is very popular for constructing detection probes for biolabeling. Scientists have discovered that these nanocrystals can enable researchers to study cell processes at the level of a single molecule and may significantly improve the diagnosis and treatment of diseases such as cancers. Qdots are either used as active sensor elements in high-resolution cellular imaging, where the fluorescence properties of the qdots are changed upon reaction with the analyte, or in passive label probes where selective receptor molecules such as antibodies have been conjugated to the surface of the dots. Qdots could revolutionize medicine. Unfortunately, most of them are toxic. Ironically, the existence of heavy metals in qdots such as cadmium, a well-established human toxicant and carcinogen, poses potential dangers especially for future medical application, where qdots are deliberately injected into the body. As the use of nanomaterials for biomedical applications is increasing, environmental pollution and toxicity have to be addressed, and the development of a non-toxic and biocompatible nanomaterial is becoming an important issue. Researchers are now proposing the use of nanoscale diamond particles as a non-toxic alternative to heavy metal qdots.
Jul 30th, 2007
Inhalation, or respiratory, therapy is a fairly old discipline of medicine that dates back to ancient times (and not always for purely therapeutic effects; witness the hookah). In the late 18th century, earthenware inhalers became popular for the inhalation of air drawn through infusions of plants and other ingredients and about 50 years ago the first pressurized metered dose inhaler was put on the market. Especially people suffering from asthma are very familiar with inhalers - devices that help deliver a specific amount of medication to the lungs. The delivery of drugs via the pulmonary route is a potentially effective form of therapy not only for asthma but also for for patients with other chronic diseases, including the debilitating hereditary disease, cystic fibrosis, type I diabetes (insulin is absorbed well through the lungs), and recently lung cancer. During inhalation therapy the drugs are delivered in aerosol form, meaning that very small particles of the drug are suspended in air (liquid particles make mist, solid particles make fume or dust). Unfortunately, state the-of-the-art aerosol delivery technologies do not allow to target aerosols to specific regions of the lung. Researchers in Germany now have show that aerosols containing magnetic nanoparticles can be guided inside the lungs and thus offer a potential new route for lung cancer treatment.
Jul 27th, 2007