Showing Spotlights 1841 - 1848 of 2140 in category (newest first):
Scientists involved in cancer research are showing a lot of interest in carbon nanotubes (CNTs) to be used in basically three cancer-fighting areas. CNTs are being developed as targeted delivery vehicles for anticancer drugs right into cancer cells - think of really, really tiny injection needles. They are also used as the therapeutic agent itself; there is research that shows that CNTs can act as nanoscale bombs that literally blow apart a cancer cell. A third area of application is using CNTs as imaging agents. Particularly single-walled CNTs (SWCNTs) are under active development for various biomedical applications. One of the issues in using CNTs for therapeutic applications is the question of how to get them to the desired place within the organism, say a tumor cell. Another significant problem in applying CNTs for biological applications is that the nanotubes do not stay suspended as discrete nanotubes in aqueous solutions. Coupling the CNT with biomolecules, such as proteins, is a good method for targeting specific sites but has the disadvantage of either reducing protein activity or CNT absorption or both. A novel method demonstrates that it is possible to achieve complete retention of enzymatic activity of adsorbed proteins as well as retention of a substantial fraction of the near-infrared (NIR) absorption of SWCNTs.
Jun 6th, 2007
In 2005, the Project on Emerging Nanotechnologies released a report by Dr. J. Clarence Davies (Managing the effects of nanotechnology) that found that U.S. legislation was inadequate. Davies concluded that nanotechnology is difficult to address using existing regulations and a new regulatory framework was needed in order to take the unique properties and risks of nanomaterials into account. This was in somewhat contradiction to what the EU Commission had found after its preliminary risk assessment workshop in 2004. The European Commission concluded that the European Union could protect health and environment by using an incremental approach and adapt existing legislation. Although there are cultural and legal differences between the EU and U.S., some people had a hard time understanding how the conclusions of the two reports could be so different. Among them, a group of scientists in Denmark and Italy decided to take a very product-specific approach and analyze the existing legislation along the life-cycle of three different commercially available products containing nanomaterials. They conclude that the 'incremental approach' could work effectively, provided due explanations and amendments are taken where necessary.
Jun 5th, 2007
To achieve the full benefits of the amazing properties of carbon nanotubes (CNTs) researchers are exploring all kinds of CNT composite materials. Material engineers are interested because this will lead to lighter,stronger and tougher materials. Another fascinating area involves CNT/polymer composite structures that will lead to a vast range of improved and novel applications, from antistatic and EMI shielding to more efficient fuel and solar cells, to nanoelectronic devices. One particular area of CNT/polymer composites is dealing with DNA-CNTs hybrids. Although researchers expect a plethora of new applications, the fact that even the formation mechanism of these complexes is not yet clear shows how early in the game this research still is. This might be due to the fact that in spite of the quite large number of experimental investigations on the interaction between DNA and CNTs, the number of theoretical studies is limited. Researchers in Germany now present, for the first time, the results of a systematic quantum mechanical modeling of the stability and the electronic properties of complexes based on single-walled carbon nanotubes, which are helically wrapped by DNA molecules.
Jun 4th, 2007
Diesel-burning engines are a major contributor to environmental pollution. They emit a mixture of gases and fine particles that contain some 40, mostly toxic chemicals, including benzene, butadiene, dioxin and mercury compounds. Diesel exhaust is listed as a known or probable human carcinogen by several state and federal agencies in the United States. Wouldn't it be nice if we could render diesel soot harmless before it gets released into the environment? Wouldn't it even be nicer if we could use this soot to manufacture something useful? Japanese scientists have come up not only with a unique technique for effectively collecting diesel soot but also a method for using this soot as a precursor for the production of single-walled carbon nanotubes. How is that as a practical example for green nanotechnology?
May 30th, 2007
One of the problems nanoscientists encounter in their forays into the nanoworld is the issue of accurate temperature measurement. Ever since Galileo Galilei invented a rudimentary water thermometer in 1593, accurate temperature measurement has been a challenging research topic and thermosensing technologies have become a field in their own right. Now, that technology has reached the nanoscale, temperature gradients are becoming essential in areas such as thermoelectricity, nanofluidics, design of computer chips, or hyperthermal treatment of cancer. Currently there is no established method how to measure the temperature gradients at the nanoscale. Most of today's probes are traditional bulk probes, the kind that gets inserted into a sample and measures the temperature. Liquid crystal films which change colors depending on temperature also have at least microscale thickness and lateral dimensions. A recent review addresses these issues and gives an overview of current and future developments for nanoscale temperature measurement technologies.
Jun 1st, 2007
One of the most common methods of film manufacture is Blown Film Extrusion. The process, by which most commodity and specialized plastic films are made for the packaging industry, involves extrusion of a plastic through a circular die, followed by "bubble-like" expansion. The resulting thin tubular film can be used directly, or slit to form a flat film. Nanoscientists now have found a way to use this very common and efficient industrial technology to potentially solve the problem of fabricating large-area nanocomposite films. Currently, the problems with making thin film assemblies are either the production cost of using complex techniques like wet spinning or the unsatisfactory results of unevenly distributed and lumping nanoparticles within the film. The new bubble film technique results in well-aligned and controlled-density nanowire and carbon nanotubes (CNTs) films over large areas. These findings could finally open the door to affordable and reliable large-scale assembly of nanostructures.
May 31st, 2007
The human body so far is the ultimate 'wet computer' - a highly efficient, biomolecule-based information processor that relies on chemical, optical and electrical signals to operate. Researchers are trying various routes to mimic some of the body's approaches to computing. Prominent among them is DNA computing, a form of computing which uses DNA and molecular biology instead of the traditional silicon-based computer technologies (see our Spotlight: "Molecular automaton plays tic-tac-toe"). Not limited to DNA, "gooware" computer scientists attempt to exploit the computational capabilities of molecules. In doing so, they expect to realize faster (massively parallel), smaller (nanoscale), and cost efficient (energy-saving) information processing devices that are very distinct from today's silicon-based computers.
May 29th, 2007
It has been 25 years since the scanning tunneling microscope (STM) was invented, followed four years later by the atomic force microscope, and that's when nanoscience and nanotechnology really started to take off. Various forms of scanning probe microscopes based on these discoveries are essential for many areas of today's research. Scanning probe techniques have become the workhorse of nanoscience and nanotechnology research. Given the 25-year development timeframe, it is surprising that even today there is no generally accepted standard for scanning probe microscopy (SPM). There is no unified SPM terminology, nor is there a standard for data management and treatment, making access and processing of SPM data collected by different types of instruments an error-prone exercise. SPM standardization has only recently begun as part of an effort by the International Organization for Standardization (ISO) the largest developer of industrial standards. Meanwhile the development of SPM instruments and analysis software continues, increasing the already large family of scanning probe microscopy.
May 25th, 2007