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Nanotechnology Spotlight – Latest Articles

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Showing Spotlights 1305 - 1312 of 2131 in category (newest first):

 

Cell surface engineering with DNA nanotechnology

cell_surface_engineering"Bionanotechnology researchers are experimenting with techniques for attaching DNA nanoarrays to cell surfaces for various reasons: to label cell surfaces with functionalized micrometer-sized patches; to deliver materials such as nanoparticles or carbon nanotubes to cell surfaces; to deliver nucleic acids into the cell for gene silencing; or to engineer microtissues of cell/cell networks by using self-hybridizing properties of single stranded DNA molecules. A team of scientists in California has now successfully attached self-assembled DNA structures to cancer cells using two different methods. This is one of the first illustrations of the biomedical relevance of DNA arrays.

Posted: Sep 22nd, 2009

Next generation nanotechnology data storage with room temperature AFM lithography

nanopatternsIn developing next generation data storage devices, researchers are employing a variety of nanotechnology fabrication and patterning techniques such as electron-beam lithography, photolithography, microcontact printing, nanoimprinting and scanning probe microscope-based lithography. A decade ago, IBM for instance introduced the Millipede Project, a thermomechanical AFM-based nanopatterning technique that was aimed at data storage systems. While this system required an AFM tip heated to 350 degrees centigrade, researchers in Korea have now demonstrated that the writing, reading, and erasure of nanoscopic indentations on a polymeric film can be achieved by using an AFM tip at room temperature - no heating required.

Posted: Sep 18th, 2009

Truly green paper battery is algae-powered

Cladophora_algaeThe batteries that power our everyday devices, from laptop computers, to mobile phones, watches, toys and flashlights, are a major source of pollution. The average household in the Western world uses about 20 batteries a year, resulting in hundreds of thousands of tons of discarded batteries that end up in landfills. When the battery casing corrodes, toxic heavy metals like mercury and cadmium can leak out and pollute soil and ground water. Researchers have been working on non-metal batteries but so far the performance of the used materials has not been good enough for commercial applications. One way to improve the performance of nonmetal-based energy storage devices is to use composite electrode materials of conductive polymers, deposited as thin layers on a suitable large surface area substrate. Researchers have now developed a novel polypyrrole-cellulose composite electrode material that is mechanically robust, lightweight, and flexible.

Posted: Sep 16th, 2009

This message will self-destruct in five seconds...

self-destructA hallmark of the Mission: Impossible series shows secret agent Phelps receiving his instructions on a tape that then self-destructs and goes up in a cloud of smoke. Existing self-erasing media are much less dramatic, of course. Most of these materials rely on photochromic molecules. One prominent example is an experimental printing technology with reusable paper developed by Xerox and PARC. While writing with light can be both rapid and accurate, photochromic 'inks' are not necessarily optimal for transforming light-intensity patterns into color variations, because they have relatively low extinction coefficients, are prone to photobleaching, and usually offer only two colors corresponding to the two states of photoisomerizing molecules. Researchers at Northwestern University have now developed a new concept that can be used to produce self-erasing pictures. In contrast to previous techniques, their method allows for multicolored pictures.

Posted: Sep 15th, 2009

Nanoparticles' random walk has implications for nanotoxicology

nanotoxicologyThe interest in exploring the use of noble metal nanoparticles for diagnostic and therapeutic imaging stems from the drawbacks of current in vivo probes. Fluorescent probes, such as fluorescent dyes and proteins, are not photostable and therefore are useful only for a limited time during the probing event. Besides imaging agents, especially gold nanoparticles are also intensely researched as target-specific vehicles for drug delivery. Due to its inert chemical properties, gold has been widely considered as one of the most stable and biocompatible materials. But studies of the biocompatibility and toxicity of gold nanoparticles in various types of cells have yielded inconclusive results: some studies show a toxic effect and high-dependence of toxicity on nanoparticle size and surface functional groups, while other studies report no significant cytotoxicity. Many of these studies did not use purified gold nanoparticles, or examine any other chemicals present in the gold nanoparticle solutions, or well characterize the physical properties, leading to these inconclusive results. Researchers have now synthesized and characterized stable, nearly monodisperse, and highly purified gold nanoparticles, and utilized them to study cleavage-stage embryos in real-time and to probe their effects on embryonic development at the single-nanoparticle level in real time.

Posted: Sep 11th, 2009

Library of 'nanobits' makes for a flexible 3D nanotechnology construction kit

NanoBitsThe folks at the European NanoHand project, whose nanogripper design we have covered in a previous Nanowerk Spotlight, seem to have loved playing with their plastic toy kits as kids. At least that's the impression you get when watching their latest video explaining their proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. They have prefabricated nanoscale needles, to be picked up by nanogrippers inside a scanning electron microscope. They then use these nanobits as ultralong tips in atomic force microscopes. The researchers call the needles 'nanobits' because they are a reminder of drill bits - you can have a library of different nanobits and then pick the one you want, and mount it where you want it.

Posted: Sep 9th, 2009

Nanotechnology researchers add fast laser printing to their nanofabrication tool box

nanopen_printingA few years ago it was discovered that the process of thermal inkjet printing can be applied to fabricate hard tissue scaffolds and, just recently, soft tissue with liquid biomaterials. Research is also underway to use inkjet printing for the fabrication of organic semiconductors, opening a route to the fabrication of high-performance and ultra low-cost electronics such as transparent electronics and thin film solar cells. As a matter of fact, the installation of the world's first silicon-ink based solar cell pilot production was completed this January. In your office, though, you have a choice between inkjet printers and (usually much faster) laser printers. And soon, nanotechnologists might have this choice, too. Researchers in California have demonstrated a novel technique for rapidly 'printing' various nanoparticles such as gold nanoparticles, carbon nanotubes, and semiconducting and metallic nanowires, on a photoconductive surface by light, much like a laser printer prints toner powder on paper.

Posted: Sep 8th, 2009

Piezoresponse force microscopy: Quantitative analysis of ferroelectric domain depth

crystal_surfaceFerroelectric domain patterns attract increasing attention owing to their potential for integrated optical and novel electronic applications. Lately, Piezoresponse Force Microscopy (PFM) has become a standard technique for the investigation of such domain patterns due to the high lateral resolution of only about 10 nm even - so no specific sample preparation is needed. In addition, due to the frequency modulated PFM technique for recording ferroelectric domains, topography and domain patterns can be recorded simultaneously and independently. Piezoresponse force microscopy is based on the deformation of the sample due to the converse piezoelectric effect. Generally, all scanning force microscopes are suited for PFM operation as long as they allow application of voltages to the tip and separate readout of the cantilever movement.

Posted: Sep 7th, 2009