Showing Spotlights 1889 - 1896 of 2340 in category All (newest first):
Pipettes (from the French: little pipe) are one of those ubiquitous tools you find in every chemical, medical or biology lab. The original pipette is made of glass and it works by creating a vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. With the advance of molecular biology, researchers required pipettes that were able to confine smaller and smaller amounts of specimen, not only for probing but also for injecting drugs, DNA etc. into cells - without damaging the cells, of course. Just a few months ago, researchers at the Brookhaven National Laboratory have developed what is thought to be the world's smallest pipette: made of a carbon-coated germanium nanowire it can hold a volume of only a few zeptoliters (a billionth of a trillionth of a liter, or one thousand cubic nanometers). Although today it even is possible to process the tip of a glass pipette to have an inner diameter as small as several tens of nanometers, this involves considerable problems in terms of the processing accuracy and the operability of the pipette, particularly in terms of locating the tip. It is generally considered that probes made from carbon nanotubes (CNTs) and nanoscale carbon pipes offer an attractive alternative to glass pipettes because of their small size, high mechanical strength, and high electrical conductivity. Researchers at the University of Pennsylvania have developed a manufacturing technique for carbon nanopipettes (CNPs) that does not require cumbersome nanoassembly and is amenable to mass production.
Dec 7th, 2007
Molecular bioelectronics is a rapidly progressing research field that is concerned with the movement of electrons and ions within living systems. This field brings together the strengths of biological reactions and biochemical interactions from nature with electronic signal detection and amplification of human electronics technology. The result will be new applications in medicine, diagnostics and therapeutics that would never be imaginable within the limitations of each separated domain. One day, bioelectronic devices could even be be directly involved in electrical communication with signal producing or controlling molecules, organelles or structures within our bodies. A more short-term goal, though, is the development of biosensors (such as enzyme-based sensors and DNA sensors) to combine the extraordinary specificity of biochemical receptors with general purpose microelectronics to develop selective probes for diagnostics, drug screening, and toxin detection. An example of recent advances in the field is the work of researchers in the U.S. who have designed an integrated nanobioelectronic system, exploiting the distinct properties of nanowires and carbon-nanotubes, for triggering reversibly and on-demand bioelectrocatalytic transformations of alcohols. Such an adaptive magneto-switchable nanobioelectronic system exploits the distinct properties of its individual nanomaterial components, can be extended to a wide range of biocatalytic systems, and offers great promise for regulating the operation of biofuel cells, bioreactors, and biosensing devices in response to specific needs.
Dec 6th, 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. Especially research related to molecular logic gates is a fast growing and very active area. Already, common logic gates, which are used in conventional silicon circuitry, can be also mimicked at the molecular level. Chemists have reported that a molecular logic gate has the potential for calculation on the nanometer scale, which is unparalleled in silicon-based devices. The general character of the concept of binary logic allows the substitution of electrical signals by chemical and optical signals, which for example opens access to a vast pool of photoactive molecules to be used for the purpose of molecular logic. Molecular logic gate structures using fluorescence changes have been studied intensively using various inputs, such as pH, metal ions, and anions. Now, South Korean scientists using solutions of fluorescent sensor molecules - and, for the first time, proteins - have developed the first soluble molecular logic gates. By using a microfluidic device, input solutions are routed into a central loop, which is filled with a fluorescent sensor solution. There the solutions mix and, in certain combinations, switch the fluorescence 'output' on or off.
Dec 5th, 2007
Machines usually require various components such as bearings, gears, couplings or pistons. As machines shrink to the micro- and ultimately nanoscale, their components of course need to shrink with them. One of the major obstacles to the realization of intricate nanomachines like nanorobots is the lack of effective processes for building freestanding nanocomponents with specific shapes and sizes. Self-assembly methods produce both organic and inorganic nano-objects with high yields through 'bottom-up' approaches. The shapes, however, in most cases are confined to rather simple forms such as spheres, rods, triangles and cubes etc. and are not suitable for the elementary components of intricate nanomachines. Meanwhile, the 'top-down' approaches including electron beam lithography and micro-contact printing etc. focus on surface patterning or fabrication of suspended objects, although they can fabricate sophisticated nanostructures. So far, the fabrication and assembly of nano-objects with specific shapes and sizes that can act as elementary components for movable nanoelectromechanical systems (NEMS) is only at the conceptual stage. New research results coming from South Korea now offer the first step toward the realization of sophisticated nanomachines, designed to perform specific tasks, with overall dimensions comparable to those of biological cells.
Dec 4th, 2007
Talking about the threat of terrorists using bioweapons is a great tool for scaring people. Using any kind of pathogen (bacterium, virus or other disease-causing organism) as a weapon certainly is a terrifying scenario; think about the near-panic the 2001 anthrax attacks in the United States caused. Letters containing anthrax spores were mailed to several news media offices and two U.S. Senators, killing five people and infecting 17 others. Can you image what panic would result from an attack that kills 5,000 people and causes 76 million illnesses? Well, as a matter of fact, foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60,000 hospitalizations, and 1,800 deaths. The Food and Drug Administration's 2005 Food Code states that the estimated cost of foodborne illness is $10-$83 billion annually. So while the U.S. spends billions of dollars securing its borders, it loses many more billions, not to mention thousands of lives, every year by not being able to keep its spinach and hamburgers safe. Apparently, talking about terrorism is much better political theater (and makes for catchier Nanowerk Spotlight titles) than discussing E. coli outbreaks. However, be it because of potential terrorists or actual contaminated food, research in microbial detection and decontamination processes increased significantly over the past years. Traditional methods of identifying and subsequently removing a pathogen are slow and cumbersome. Now, using nanotechnology, researchers have designed a novel biosensing system that can identify E. coli in just five minutes and remove up to 88% of the target bacteria.
Dec 3rd, 2007
An important property of polyaniline (PANi), a polymer, is its electric conductivity. This makes it suitable for the manufacture of electrically conducting fibers. Consequently, PANi and other conductive polymers have been extensively studied for optical and electronic applications and many practical syntheses of one-dimensional (1D) nanostructured PANi have already been developed. However, preparation of water-soluble, conductive PANi nanowires with controllable morphologies and sizes, especially with good processibility, is still a big challenge. A possible solution could lie in the use of self-assembled proteins, such as plant viruses, as nanotemplates for the synthesis of these nanowires. For instance, genetically modified viruses have already been proposed as templates for the assembly of nanometer-scale components of electronic circuits. Researchers now have successfully demonstrated the fabrication of water-dispersible, conductive PANi nanowires using the rod-like tobacco mosaic virus (TMV) as a template. They have also shown that much longer conductive PANi/TMV nanowires (greater than the length of a native TMV particle) can be formed by a hierarchical assembly process.
Nov 30th, 2007
Governments always struggle when faced with regulating highly complex subject matters such as nanotechnologies. Primarily concerned with managing the potential risks to the environment, human health and the safety of workers (EHS), regulators often feel overwhelmed by the complexity and novelty of new technologies, stymied by a lack of data, and confused by conflicting research findings and advice from various interest groups. In the meantime, against a backdrop of a legal environment that ranges from gaping holes to regulatory vacuum, research organizations and early-adopting industry players push ahead with the new technology. Not being able to create any breathing room for lengthy political and legal considerations, the last 15-20 years have seen several governments adopting voluntary environmental programs (VEPs), arguing that this is the only viable proportional option for the time being. It is estimated that there are some 300 VEPs in the European Union and over 200 in the United States, dealing with matters such as climate change, energy, waste, water, toxic materials, agriculture, manufacturing, mining, forestry, hotels, hospitals, and financial institutions. If these voluntary programs work is subject to debate - some apparently do, some less so. In the case of manufactured nanomaterials, the risk properties remain largely unknown and it is unclear what exactly should be regulated. For the VEPs that are in place for nanomaterials, governments are urging companies to submit health and safety information on the nanomaterials they produce or commercialize. In order to investigate whether voluntary government programs will be sufficient to ensure the safety of manufactured nanomaterials, researchers have analyzed a sampling of voluntary programs in the fields of environmental health and safety in the United States over the past 20 years, with a view towards their applicability in the case of manufactured nanomaterials
Nov 29th, 2007
In most mechanical systems, friction or vibration are often considered to be negative attributes because they results in wear and unnecessary energy dissipation. Tribological issues such as friction, wear, and vibration have always plagued developers of small-scale mechanical devices. As devices get smaller and even reach the nanoscale, this problem becomes more acute due to the extreme surface-to-volume ratios these devices have. In nanomachines damage to even a single atom layer could mean disaster. Nanotechnology researchers basically have two ways to address this problem: they either could apply traditional tribological methods by trying to integrate dampers and low-friction materials with their nano- and microdevices - which becomes increasingly complex and costly at the nanoscale - or they could try and develop intrinsic damping materials that have hard, low-fiction surfaces to lower wear yet still maintain high compressibility and elastic properties to provide resistance to vibrations and shocks. Finding materials that address these problems individually is not difficult but fabricating a structure that combines all of them is nearly impossible because of the conflicting nature of these attributes. However, in what researchers have dubbed a 'nanomattress', a unique structure containing aligned carbon nanotubes (CNTs) covered with a hard layer of diamond-like carbon (DLC) results in a carbon-based composite material with outstanding mechanical properties.
Nov 28th, 2007