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Showing Spotlights 1041 - 1048 of 2055 in category (newest first):

 

A magnetic leaf

biotemplated_leafNature can provide very useful templates for technical applications. A group of scientists have devised a new process involving the almost complete conversion of a leaf skeleton into magnetic iron carbide. To do this, they treated the leaf with iron acetate, nitrogen and heat. This technique can be used to recreate all natural carbonaceous structures with metal carbides. The result is not just beautiful, but also very useful. The new technique enables the conversion of metal carbides into intricate microstructures in just one step. Biology's intricate forms provide a wide range of templates for a variety of applications. Wide-ranging biological forms can be used as templates for filigree metal carbide structures using this method.

Posted: Sep 22nd, 2010

Carbon dioxide capture with nanometric thin-film membranes

carbon-dioxide-emissionOne possible option for reducing CO2 emissions from power plants is to capture them before they hit the atmosphere and store the gas underground. This technique is called Carbon dioxide Capture and Storage. However, before CO2 can be stored, it must be separated from the other waste gases resulting from combustion or industrial processes. Most current methods used for this type of filtration are expensive and require the use of chemicals. Nanotechnology techniques to fabricate nanoscale thin membranes could lead to new membrane technology that could change that. Current membranes are in many cases not competitive for large scale applications, because their permeance for carbon dioxide is not high enough. Researchers in Germany have now reported the development and manufacturing of nanometric thin film membranes with record performance.

Posted: Sep 21st, 2010

Pinning neurons in place with nanopillars

nanopillar_pinning_neuronStudies of the interface between nanostructures and live cells have been increasing rapidly in the past few years. Because the size of nanostructures is often comparable to internal organelles inside the cell, those nanostructures are very useful in serving as sensors to detect biological events inside a live cell. For neuroscientists, monitoring the electrical signaling within neural networks is a fundamental issue. It has proven to be very challenging to monitoring individual neuron activities in a neuronal network for an extended time, which demands stable and specific neuron-electrode correspondence. Unfortunately for the scientists, neurons tend to migrate as far as hundreds of micrometers. With a new techniques, researchers have managed to engineer unique nanostructures that foster, rather than impose, residence of neuron cell bodies atop the electrode of interest.

Posted: Sep 16th, 2010

Photoconductive Atomic Force Microscopy for understanding nanostructures and device physics of organic solar cells

Plastic solar cells are emerging as alternative energy sources for the future because of their potential for cheap roll-to-roll printing, ease of processing, light-weight and flexibility. However, their current performance is still low for practical applications which partially originate from the poor understanding of device physics and nanoscale morphology of the photoactive layer. Photoconductive atomic force microscopy (pcAFM)is a powerful characterization tool to better understand the complex optoelectronic and morphological phenomena of organic solar cells at the nanoscale. This article briefly described the applicability of the pcAFM technique for analyzing solution-processed, polymer and small molecule bulk heterojunction solar cells. Due to the nature of charge generation, transport and collection occurring at the nanometer scale, the useful information on device operation can be lost from macroscopic measurements.

Posted: Sep 15th, 2010

The supersensitive detection of explosives by nanowire nano-nose arrays

nanonoseSemiconducting 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.

Posted: Sep 14th, 2010

Detecting signs of early-stage cancer with graphene oxide and carbon nanotubes

grapheneCurrent 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.

Posted: Sep 13th, 2010

Novel optical procedure greatly facilitates nanotube characterization

carbon_nanotubesProgress 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.

Posted: Sep 10th, 2010

A novel single electron pump based on a carbon nanotube

single_electron_pumpElectron 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.

Posted: Sep 9th, 2010