Researchers at the Cidetec-IK4 Research Centre at San Sebastian in Spain have developed a new type of electrochemical nanobiosensor capable of detecting mutations in DNA much more rapidly than before. The sensor technology also offers the possibility to be extended to the detection of other types of molecule.

The nanobiosensor comprises a nanotransistor, the cable of which is a carbon nanotube modified by a polymer that enables DNA to anchor. High selectivity can be achieved without the need to modify the DNA and the sensor is capable of detecting sequences, such as those implicated in particular genetic diseases directly.

Source: Basque Research

Journal reference: Nano Letters, 2009; 9 (2): 530

Cidetec-IK4

Posted: March 10th, 2009 under Advanced medtech, Nanomedicine, Nanotechnology.
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Researchers at Sandia National Laboratories, Livermore, California have succeeded in developing a device based on carbon nanotubes that can detect the entire visible spectrum of light and which may find potential uses in artificial retinas and other light gathering applications such as solar cells and miniature cameras for use in low light conditions. Earlier attempts at similar devices were only able to detect specific wavelengths.

The device utilizes carbon nanotubes decorated with three different types of chromophores, which are molecules that change shape in response to particular wavelengths of light… in the case of the Sandia research red, green and blue wavelengths. This change in shape alters the orientation of the chromophores in relation to the nanotube which, in turn, alters the conductivity of the nanotube to give a signal that can be measured. Because of their size, the nanotubes have intrinsically high resolution… around the diameter of each nanotube or 1nm.

The researchers believe that the process of manufacturing such devices could be scaled up and are also working on versions of the device that can detect infrared light, and which are more sensitive.

Source: MIT Technical Review

Posted: March 10th, 2009 under Advanced materials, Physics, Advanced medtech, Nanomedicine, Nanotechnology.
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Researchers in South Korea have recently constructed nanotubular structures from branched hydrocarbon chains with attached pyrene groups. By adding cyclodextrins the branches rearrange from a vesicular structure to nanoscale tubes with cyclodextrin “cuffs”. The development is interesting in that the pyrene groups fluoresce and the cyclodextrin “cuffs” can be further linked with a variety of functional groups that “dangle” from the tubes into solution and can thus form useful surfaces for biosensing.

The team, led by Chulhee Kim and Chiyoung Park at Inha University, demonstrated this biosensing ability by attaching biotin to the surfaces of the nanotubes. Biotin binds specifically to the proteins avidin and streptavidin. By adding streptavidin bound to gold nanoparticles, the gold was brought into the vicinity of the pyrene groups “switching them off”. If a mixture of avidin and gold-bound streptavidin are added, the avidin binds preferentially to the biotin allowing the gold-streptavidin only to bind to sites not occupied by the avidin. The level of fluorescence is, therefore, related to the avidin concentration.

The team also suggest that the ability of the nanotubes to bind metal nanoparticles could also have potential applications in nanoelectronics. 

Source: Nanowerk

Abstract

Posted: November 18th, 2008 under Nanomedicine, Nanotechnology.
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Researchers at Gothenburg’s Chalmers University of Technology have succeeded in making self-assembling DNA strands capable of guiding light along their length. The team, led by Bo Albinsson, used a mixture of DNA and light-sensitive molecules called YO chromophores to make strands with a light absorbing molecule at one end and a light emitting molecule at the other. In testing the assembled strands, the team found that they transmitted around 30% of the light received by the absorbing chromophore to the emitting chromophore. The system resembles the photonic mechanisms that organisms such as algae use to transport light to parts of the cell where the energy can be converted.

While it is currently impossible to know exactly where the chromophores insert themselves into the DNA strands during self assembly, researchers believe that the scale distances involved may offer opportunities to develop the system for use in nanoscale electronics interconnects, molecular computers and artificial photosynthetic systems.

Source: New Scientist

Paper: Journal of the American Chemical Society

Posted: November 18th, 2008 under Advanced materials, Nanomedicine, Nanotechnology.
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One of the great challenges in designing very small implants and devices to work inside the human body is finding a suitable source of power. Now researchers at the US National Institute of Standards and Yale University inspired by the mechanisms of electrical energy production in the electric eel, Electrophorus electricus, have described a method for producing artificial cells that can utilise the body’s biological ion concentration gradients.

Jian Lu from the Department of Chemical Engineering, Yale University, and David Lavan of NIST calculated the conversion of ion concentration gradients into action potentials across different nanoscale conductors in a model electrogenic cell and, using parameters extracted from their numerical model, designed an artificial cell based on the optimum selection of these conductors. They suggest that the level of power output attainable from the system could be sufficient to power novel miniaturised medical devices such as retinal implants.

Read more at Science Daily

Posted: November 17th, 2008 under Nanomedicine, Nanotechnology.
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One of the problems with implanting material into the human body is that proteins tend to build up on the surfaces of the implanted material. In the case of applications like biosensing surfaces, e.g. for glucose monitoring in diabetes, and membranes this can cause significant problems.

Now a new study by researchers at North Carolina State University led by Dr Roger Narayan, has found that nanoporous ceramic membranes can avoid both protein build-up and rejection by the body. The researchers hope that this may open up new possibilities in developing dialysis membranes, as well as other implant surfaces, where poor biocompatibility has proved a problem in the past.

Source: PhysOrg.com

Posted: November 11th, 2008 under Chemistry, Nanomedicine, Nanotechnology.
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There are a number of current approachs that are evaluating the potential of carbon nanotubes as potential delivery vehicles for drugs but Dr Balaji Panchapakesan at the
University of Delaware has come up with a new approach.

His idea is to hydrate them before injecting them into a tumour site and then target them with carefully tuned laser light which causes the trapped water to absorb energy and boil, causing the nanotubes to “explode”, heating and destroying the surrounding cancer tissue. The nanotubes can, additionally, be labelled with antibodies that bind to specific cancer cells and anticancer drugs added to the water.

Read the patent application.

Source: New Scientist

Posted: November 11th, 2008 under Nanomedicine, Nanotechnology.
Comments: 1

It’s well-known that a gecko can cling to almost any surface, including smooth glass, due to the anatomy of its feet. Each toe is covered in microscopic hairs called setae which have yet smaller branches, called spatulae, at the tips. These present a large surface area to the substrate maximising the effect of van der Waals forces.

Researchers, led by Liming Dai at the University of Dayton in Ohio and Zhong Lin Wang at the Georgia Institute of Technology, have now made a material from carbon nanotubes that is up to 10 times stickier than gecko feet. They grew the carbon nanotubes on a silicon wafer to form a “forest” of vertical nanotube trunks with a canopy of tangled ends at the canopy level, mimicking the gecko’s spatulae and presenting a large surface area to any surface in contact. The new material is superior to some earlier competitors in that it can be easily loosened by varying the angle of pull.

Liming sees some potential applications for the sticky material… as carbon nanotubes are excellent conductors the material could replace solder in electronics in some situations or traditional adhesives in space where vacuum causes the adhesives to dry out and fail quickly.

Source: New Scientist

Posted: October 30th, 2008 under Advanced materials, Physics, Chemistry, Nanotechnology.
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Nanotechnology is producing a wealth of new products based on utilising features and characteristics at the nanoscale including microelectronics and micromachines with moving parts. One problem at such a tiny scale is how to switch them on and off or control them as needed.

In a new study, Dr Harold Zandvliet and colleagues at the University of Twente in the
Netherlands have developed a nanoscale mechanical device, grown on a wafer of germanium, that can respond to a tiny electrical current from the tip of a scanning tunneling microscope to make two atom pairs move like the flippers of a nanoscale pinball machine. The researchers state that understanding the mechanism can provide insights into the opportunities for future atomic-scale devices.

Paper published in Nano Letters

Source: Nanotechnology Now

Posted: October 30th, 2008 under Advanced materials, Physics, Chemistry, Advanced medtech, Nanotechnology.
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Scientists from the John Innes Centre (UK), Institut Pasteur (France) and Scripps Research Institute (California, USA) have shown that a virus that withstands extreme conditions and that can infect bacteria living in temperatures of up to 80⁰C and pH 2-3, may be used as a stable nanobuilding block.

The virus, a rod-shaped rudivirus called SIRV2, infects the thermoacidiphilic bacterium Sulfolobus islandicus which is found in hot volcanic springs. The team subjected the virus to a variety of harsh environments within the laboratory and found that the viral capsule was able to withstand such conditions which make it a promising candidate as a viral nanoparticle (VNP), a form of particle that can self-assemble with high precision. To be suitable as a VNP, however, the particles must be amenable also to chemical or genetic modification and the team was able to successfully target modifications to both the ends and the body of the virus enabling it to be built up into layers or arrays.

The team thinks that the new VNP, by virtue of its stability under extreme conditions and possibility for alignment in different ways, may find useful applications in liquid crystal assembly, nanoscale templates, nanoelectronics, and biomedical applications.

Source: PhysOrg

Posted: October 28th, 2008 under Advanced materials, Advanced medtech, Nanotechnology.
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