Showing Spotlights 2249 - 2256 of 2424 in category All (newest first):
Sophisticated biomolecular motors have evolved in nature, where motor proteins actively control the delivery and assembly of materials within cells. In contrast, the development of synthetic nanomotors is in its infancy. Such nanomotors are currently explored for an increasing number of applications in hybrid bionanodevices. Along these lines, gliding motility assays, where reconstituted microtubule filaments are propelled over a substrate by surface-attached motor proteins, have been used to transport micro- and nanosized objects, such as small beads, quantum dots or DNA molecules. However, one prerequisite for controllable nanotransport is the reliable guiding of filament movement along predefined paths, a challenging task that has recently been achieved only via costly and labor-intensive topographical surface modifications. Researchers have now demonstrated a novel approach for the nanostructuring of surfaces with functional motor proteins. In contrast to all other current methods, their approach allows the three-dimensionally oriented deposition of proteins on surfaces, being the result of first binding them to the highly oriented and regulated structures of microtubules and then transferring them to the surface.
Oct 20th, 2006
Nucleoside analogues, which are a class of therapeutic agents, display significant anticancer or antiviral activity by interfering with DNA synthesis. They work by incorporating into the elongating DNA strands and terminating the extension process. However, they also affect normal cell growth, such as bone marrow cells, so there can be significant toxic effects. Further limitations to their use are relatively poor intracellular diffusion, rapid metabolism, poor absorption after oral use, and the induction of resistance. French and Italian researchers have now come up with a completely new approach to render anticancer and antiviral nucleoside analogues significantly more potent. By linking the nucleoside analogues to squalene, a biochemical precursor to the whole family of steroids, the researchers observed the self-organization of amphiphilic molecules in water. These nanoassemblies exhibited superior anticancer activity in vitro in human cancer cells.
Oct 19th, 2006
Paper manufacturing is one of the mainstays of economic infrastructure and paper products influence many aspects of business and personal life. Pulping, process chemistry, paper coating, and recycling are key areas that can benefit from nanotechnology methods. One such method, layer-by-layer (LbL) assembly, is of great interest of its usage in the field of nanocoating. It allows creating nanometer-sized ultrathin films both on large surfaces and on microfibers and cores with the desired composition. Researchers at Louisiana Tech University have developed a simple and cost effective technique to fabricate an electrically conductive paper by applying layer-by-layer nanoassembly coating directly on wood microfibers during paper making process. Nanocoated wood microfibers and paper may be applied to make electronic devices, such as capacitors, inductors, and transistors fabricated on cost-effective lignocellulose pulp. The use of a conductive nanocoating on wood fibers can open the door for the future development of smart paper technology, applied as sensors, communication devices, electromagnetic shields, and paper-based displays.
Oct 18th, 2006
Controlling the shape of nanostructures is one of the challenging issues presently faced by synthetic chemists and materials engineers. Various shapes of nanomaterials, such as sphere-, rod-, wire-, triangle-, cube-, and tube-outlines have been synthesized by various approaches. However, to produce nanostructures with high monodispersity is still one of the major issues to be solved. Most work in this area focused on inorganic or synthetically organic materials. Using pure biomolecules to produce nano- or micro-structures, without the assistance of inorganic materials, is rare. Biocompatible nanospheres have been and remain of intense interest for biosensor, drug delivery, and biomedical contrast imaging. A new research report coming out of China now shows that highly monodispersed nanospheres of cystine (a sulfur-containing amino acid) aggregate were successfully produced by a quite simple method without the assistance of any other inorganic materials. This work could be of great significance in the production of nanomaterials, biosensors, and drug delivery.
Oct 17th, 2006
As the semiconductor industry continues to miniaturize in following Moore's Law, there are some real challenges ahead, particularly in moving deeper and deeper into the nano length scale. In particular, sustaining the traditional logic MOSFET (metal-oxide-semiconductor field-effect transistor) structure, design, and materials composition will be especially difficult, particularly beyond the 22 nm node. Nanocables, consisting of a range of materials, offer potential solutions to these problems and may even be an alternative to today's MOSFET. A group of researchers from several European countries now reports the synthesis of a magnetically tunable nanocable array, combining separate hard and soft magnetic materials in a single nanocable structure. The combination of two or more magnetic materials in such a radial structure is seen as a very powerful tool for the future fabrication of magnetoresistive, spin-valve and ultrafast spin-injection devices with nonplanar geometries.
Oct 16th, 2006
With the advent of nanoscience and technology, a new area has developed in the area of textile finishing called "Nanofinishing". Growing awareness of health and hygiene has increased the demand for bioactive or antimicrobial and UV-protecting textiles. Coating the surface of textiles and clothing with nanoparticles is an approach to the production of highly active surfaces to have UV blocking, antimicrobial, flame retardant, water repellant and self-cleaning properties. While antimicrobial properties are exerted by nano-silver, UV blocking, self-cleaning and flame-retardant properties are imparted by nano-metal oxide coatings. Zinc oxide (ZnO) nanoparticles embedded in polymer matrices like soluble starch are a good example of functional nanostructures with potential for applications such as UV-protection ability in textiles and sunscreens, and antibacterial finishes in medical textiles and inner wears.
Oct 13th, 2006
Semiconductor photonics, electronics and optoelectronics infrastructure is at the core of the information society. As the length scales of electronic devices continue to shrink, the cost of traditional approaches to device fabrication involving lithography is becoming excessive. It is regarded that self-assembled growth methods are a solution to the problem of fabricating smaller devices at a lower cost. Self-assembled quantum dots (QDs) are providing the possibility of new devices for this infrastructure in the short, medium and long term. QDs are ideal for the study of the fundamental properties of nanostructures, which is applicable across the nanotechnology and nanoscience sector. Research in self-assembled semiconductor QDs is therefore characterized by a remarkably well-matched combination of the two main motivations for scientific research, namely academic interest and the potential for industrial applications. As a consequence, there is an intense scientific activity in materials growth, structural characterization, optical and transport spectroscopy, device engineering and computational modeling. The field of self-assembled semiconductor nanostructures started in 1985 in Europe by a French group at the Centre National d'Etudes des Telecommunications - CNET.
Oct 12th, 2006
DNA computing is a form of computing which uses DNA and molecular biology instead of the traditional silicon-based computer technologies. Molecular computation is currently focused on building molecular networks analogous to electrical engineering designs. These networks consist of logic gates, which perform Boolean logical operations such as AND, NOT, and OR on one or more inputs to produce an output. While individual molecular gates and small networks have previously been constructed, these gates are yet to be integrated at higher levels of complexity. Such integration in electrical engineering arises from massive parallelism and interconnections, rather than fundamental component complexity. The ability to truly integrate molecular components remains crucial for the construction of next-generation molecular devices. Researchers have now succeeded in building a medium- scale integrated molecular circuit, integrating 128 deoxyribozyme-based logic gates, 32 input DNA molecules, and 8 two-channel fluorescent outputs across 8 wells.
Oct 11th, 2006