Showing Spotlights 1785 - 1792 of 2791 in category All (newest first):
Semiconducting nanowires are known to be extremely sensitive to chemical species adsorbed on their surfaces. For a nanowire device, the binding of a charged analyte to the surface of the nanowire leads to a conductance change, or a change in current flowing through these tinny wires. Their one-dimensional nanoscale morphology and their extremely high surface-to-volume ratio make this conductance change to be much greater for nanowire-based sensors versus planar field-effect transistors, increasing the sensitivity to a point that single molecule detection is possible. In the last decade, it has been demonstrated that these new nanostructures can be used for the detection of multiple biomolecular species of medical diagnostic relevance, such as DNA and proteins. In recent work, researchers have used the ultrasensitive recognition properties of semiconducting silicon nanowires to demonstrate the most sensitive ever published sensing of explosives reported so far.
Sep 14th, 2010
Current protein detection approaches are mainly dominated by heterogeneous immunological (or separation) assay methods. These assays are usually low-throughput and frequently require multiple steps including multiple incubation and careful washing of a surface onto which the labeled reagent has bound. In contrast, homogenous immunoassays can overcome these problems. In these assays, the signal is affected by binding and can often be run without a separation step. Such assays can frequently be carried out simply by mixing the reagents and sample and making a physical measurement. Researchers in China and Japan have now developed a graphene oxide based fluorescence assay for fast, ultra-sensitive, and selective detection of protein and demonstrated its use for detection of a prognostic indicator in early-stage cancer, cyclin A2.
Sep 13th, 2010
Progress towards SWCNT-based technology has commenced slowly even though the remarkable potential has been realized soon after their discovery in 1991. A first major drawback is related to the characterization of functionalized SWCNTs. Since carbon nanotubes are intrinsically insoluble in common organic solvents and water, their surface needs to be modified by covalent or noncovalent functionalization in order to increase their poor processeability. Accordingly, the successful derivatization needs to be analyzed, usually by cumulating evidence from a variety of independent spectroscopic and microscopic techniques. However, it is exactly this diversity that renders nanotube characterization highly challenging, as no standard protocol for the precise analysis has yet been established. Taken as individual methods, every characterization technique has its own limitations and restrictions so that the precise analysis can only be achieved by combining the information from the different techniques. Researchers in Germany have presented significant progress towards reaching this goal by describing a readily accessible and low-cost methodology towards correlating spectroscopic and microscopic information by the aid of the optical visualization of one dimensional nano-scaled objects such as SWCNTs.
Sep 10th, 2010
Electron pumps are devices that can transfer a certain number of electrons during each pumping cycle. Besides being of fundamental interest to physicists, single-electron pumps have a potential for practical application in metrology, acting as an accurate frequency-current converter. The general goal of this field is to build a current standard based on the electrical charge of a single electron in order to achieve high accuracy for current measurement. A device called single-electron transistor (SET) can confine charges down to single electron level and hence is applicable for quantized current generation. Attempts to generate quantized current in nanotubes have been made with various methods over the past few years, but were not very successful in obtaining a high degree of current quantization. A research team in Germany has now demonstrated the feasibility of using a single molecule - in this case, a single-walled carbon nanotube - for the generation of quantized electric current.
Sep 9th, 2010
Single-walled carbon nanotube (SWCNT) based thin film transistors (TFTs) could be at the core of next-generation flexible electronics - displays, electronic circuits, sensors, memory chips, and other applications that are transitioning from rigid substrates, such as silicon and glass, to flexible substrates. What's holding back commercial applications is that industrial-type manufacturing of large scale SWCNT-based nanoelectronic devices isn't practical yet because controlling the morphology of single-walled carbon nanotubes is still causing headaches for materials engineers. In an effort to develop a new and effective solution process of isolated SWCNTs, researchers in Japan have now demonstrated a novel solution process to fabricate high-performance TFTs of individual SWCNTs using DNA.
Sep 7th, 2010
Unlike most biological membranes, polymeric, nanometer-thin membranes are very stable and can withstand considerable pressure. This is an essential requirements for separation processes such as in water purification and desalination. Because their mechanical stability can be combined with flexibility and chemical functionality, polymer nanomembranes are also intensely researchers as materials for actuators and microsensors. They have also entered the biomedical field as artificial nacre and as a novel material used in surgery. Crosslinking of a spin-coated precursor solution, a common fabrication technique, reduces the interactions between the polymer chains and the environment and thus impairs the sensitivity and flexibility of the films. Researchers in Germany have now developed the first freestanding polymer brush, grafted from a crosslinked monolayer (nanosheet) that provides mechanical stability and structural integrity.
Sep 2nd, 2010
Australian researchers have introduced the Nanopatch - a new way of delivering vaccines to the skin and potentially a safer, cheaper alternative to traditional needle vaccines. The Nanopatch comprises arrays of densely packed projections with a defined geometry and distribution designed to physically target vaccines directly to thousands of epidermal and dermal antigen presenting cells. These miniaturized arrays are two orders of magnitude smaller than standard needles and are also much smaller than current microneedle arrays. The core idea is to achieve improved vaccine efficiency and effectiveness - over the needle and syringe - through precise targeting of vaccines to skin strata, achieved by device miniaturization utilizing micro- and nanotechnologies.
Aug 31st, 2010
Improvements in the design of medical equipment for better streamlined functionality and performance is influenced by a number of critical factors. The research, design, modeling, testing, prototyping, and FDA and EU approvals of new mechatronic devices, or the integration of changes to existing designs, usually represents a sizable capital investment of resources well before the equipment goes into serial production. Factored into the medical device's product development are considerations such as size of the equipment, speed of operation, heat generation, portability, handling of static or kinetic loads, power sources, measuring systems, vacuum and nonmagnetic requirements, sensors, machine controls, component part wear and diagnostics. A key impetus for medical and bioresearch companies to engage upon these involved product development cycles is the opportunity to capitalize on advances in technology for the manufacture of better operating, lower cost and more efficient equipment and devices.
Aug 27th, 2010
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