Microelectromechanical based systems

In the fight against cancer, nanotechnology introduces unique approaches to diagnosis and treatment that could not even be imagined with conventional technology. New tools engineered at sizes much smaller than a human cell will enable researchers and clinicians to detect cancer earlier, treat it with much greater precision and fewer side effects, and possibly stop the disease long before it can do any damage.

Take a Video Journey Into Nanotechnology to see how this field of science is changing the way we look at cancer.

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Imagine….Something 80,000 times smaller than the breadth of the ridge on a fingertip unlocking a new frontier into cancer research. Nanotechnology, the science of building small, is changing the way we look at cancer…more importantly the way we look at diagnosis and treatment.

Nanotechnology allows researchers to build new tools that are actually smaller than cells, giving them the opportunity to attack cancer cells at the cellular and genetic level. This technology not only enables health practitioners to detect cancer earlier but also holds the promise of stopping cancer before it even develops.
This revolutionary approach is so precise, doctors will be able to design a unique treatment for an individual’s own medical and genetic profile.

Based on computer chip technology, diagnostic devices such as nanoarrays are thousands of times more sensitive and accurate than current techniques. Because of their size, multiple lab tests can be done more rapidly and at a much lower cost using one nanodevice instead of many.

Nanoshells can be linked to antibodies that recognize tumor cells. Once they are taken up by the cancer cells, near-infrared light is applied, killing only the tumor and leaving neighboring, healthy cells intact.

Scientists are engineering nanoparticles such as dendrimers to seek out and destroy cancer cells. This amazing technology can be customized for targeted drug delivery, improved imaging, and near real-time confirmation of cancer cell death.

Moving research from bench to bedside is an important goal of the National Cancer Institute’s Alliance for Nanotechnology in Cancer. A collaborative plan is underway to share research and development information across scientific disciplines and around the world.

As biomedical applications of nanotechnology evolve, scientists are ensuring that nanodevices are safe for both the body and the environment. The National Cancer Institute is optimistic that through coordinated and responsible development, nanotechnology will dramatically change cancer patient care. The science is at our fingertips.

TEXT CREDIT: NCI Alliance for Nanotechnology in Cancer

VIDEO CREDIT: worldschoiceproducts

3-D nanoparticle in atomic resolution Empa/ETH Zurich study published in Nature

In chemical terms, nanoparticles have different properties from their «big brothers and sisters»: they have a large surface area in relation to their tiny mass and at the same time a small number of atoms. This can produce quantum effects that lead to altered material properties. Ceramics made of nanomaterials can suddenly become bendy, for instance, or a gold nugget is gold-coloured while a nanosliver of it is reddish.

New method developed

The chemical and physical properties of nanoparticles are determined by their exact three-dimensional morphology, atomic structure and especially their surface composition. In a study initiated by ETH Zurich scientist Marta Rossell and Empa researcher Rolf Erni, the 3D structure of individual nanoparticles has now successfully been determined on the atomic level. The new technique could help improve our understanding of the characteristic of nanoparticles, including their reactivity and toxicity.

Gentle imaging processing

For their electron-microscopic study, which was published recently in the journal «Nature», Rossell and Erni prepared silver nanoparticles in an aluminium matrix. The matrix makes it easier to tilt the nanoparticles under the electron beam in different crystallographic orientations whilst protecting the particles from damage by the electron beam. The basic prerequisite for the study was a special electron microscope that reaches a maximum resolution of less than 50 picometres. By way of comparison: the diameter of an atom measures about one Ångström, i.e. 100 picometres.

To protect the sample further, the electron microscope was set up in such a way as to also yield images at an atomic resolution with a lower accelerating voltage, namely 80 kilovolts. Normally, this kind of microscope – of which there are only a few in the world – works at 200 – 300 kilovolts. The two scientists used a microscope at the Lawrence Berkeley National Laboratory in California for their experiments. The experimental data was complemented with additional electron-microscopic measurements carried out at Empa.

Sharper images

On the basis of these microscopic images, Sandra Van Aert from the University of Antwerp created models that «sharpened» the images and enabled them to be quantified: the refined images made it possible to count the individual silver atoms along different crystallographic directions.

For the three-dimensional reconstruction of the atomic arrangement in the nanoparticle, Rossell and Erni eventually enlisted the help of the tomography specialist Joost Batenburg from Amsterdam, who used the data to tomographically reconstruct the atomic structure of the nanoparticle based on a special mathematical algorithm. Only two images were sufficient to reconstruct the nanoparticle, which consists of 784 atoms. «Up until now, only the rough outlines of nanoparticles could be illustrated using many images from different perspectives», says Marta Rossell. Atomic structures, on the other hand, could only be simulated on the computer without an experimental basis.

«Applications for the method, such as characterising doped nanoparticles, are now on the cards», says Rolf Erni. For instance, the method could one day be used to determine which atom configurations become active on the surface of the nanoparticles if they have a toxic or catalytic effect. Rossell stresses that in principle the study can be applied to any type of nanoparticle. The prerequisite, however, is experimental data like that obtained in the study.

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Literature Van Aert S, Batenburg KJ, Rossell MD, Erni R & Van Tendeloo G: Three-dimensional atomic imaging of crystalline nanoparticles, Nature (2011), doi: 10.1038/nature09741 Author: Simone Ulmer/ETH Life

Further information
Dr. Rolf Erni, Empa, Electron Microscopy Center, +41 44 823 40 80, rolf.erni@empa.ch
Dr. Marta D. Rossell, ETH Zurich, Laboratory for Multifunctional Materials, +41 44 633 67 07, rossell@mat.ethz.ch

Contact: Dr. Rolf Erni rolf.erni@empa.ch 41-448-234-080 Swiss Federal Laboratories for Materials Science and Technology (EMPA)

Exposing ZnO nanorods to visible light removes microbes, Photocatalysis for immobilizing bacteria in water using solar light on ZincOxide nanorods

The practical use of visible light and zinc oxide nanorods for destroying bacterial water contamination has been successfully demonstrated by researchers at the Asian Institute of Technology (AIT). Nanorods grown on glass substrates and activated by solar energy have been found to be effective in killing both gram positive and gram negative bacteria – a finding that has immense possibilities for affordable and environmentally friendly water purification techniques.

“Most studies so far either work on the use of ultraviolet light or involve a suspension of nanoparticles,” revealed Prof. Joydeep Dutta, director of the Center for Excellence in Nanotechnology at AIT. The AIT research group has dispensed with both. Instead of using a suspension of nanoparticles, which have to be removed later after the water purification process, or relying on UV light, the group demonstrated a system featuring visible light and ZnO nanorods. “The key concept was to incorporate deliberate defects in ZnO nanorods by creating oxygen vacancies and interstitials, which then allows visible light absorption,” he explained.

Environmentally friendly approach

Researchers at AIT’s Center of Excellence in Nanotechnology.

Such ZnO nanorods grown on glass were tested on Escherichia coli and Bacillus subtilis bacteria, which are commonly used as model microbes. In the dark, ZnO dissolves slowly releasing zinc ions, which have anti bacterial properties, as it penetrates the bacterial cell envelope thereby thwarting the growth of microbes. Under well lit conditions, the effect is doubled with both photocatalysis and zinc ions playing their part in killing the microbes.

The implications of these experiments are enormous. “Since ZnO has now been tested under solar light, instead of the traditionally used UV light, the potential for commercial applications is huge, particularly since the levels of zinc ions removed from the rods to the water are safe for human consumption,” added Dutta.

The team, which also includes Dr. Oleg V Shipin, Ajaya Sapkota, Dr. Alfredo J Anceno, Mr. Sunandan Baruah and Ms. Mayuree Jaisai, is continuing its work on photocatalysis for use in water decontamination.

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Contact: Prof. Joydeep Dutta nano@ait.ac.th WEB: Asian Institute of Technology