Volume 3 Issue 7, July 2008

It is difficult to be definitive about certain aspects of nanotechnology, especially the use of nanoparticles in medical applications. Chris Toumey looks at two views.

Nanoparticles can improve the spatial resolution of mass spectrometry imaging of mammalian tissues.

Hybrid devices that rely on the movement of both electrons and ions might one day challenge conventional silicon electronics by exploiting both classical and quantum electron transport.

Direct injection of long multiwalled carbon nanotubes into the abdominal cavity of mice produces asbestos-like pathogenic behaviour. What does this finding mean for nanotube safety?

A stencilling technique for depositing arrays of nanoscale ferroelectric capacitors on a surface could be useful in data storage devices.

Electron interferometry can be used to measure strain with nanoscale resolution in electronic devices by exploiting a simple idea found in physics textbooks.

It will take a concerted effort for nanomachines to express themselves on a macroscopic scale. Could self-organizing helical polymers help?

The performance of metal electrodes used for studying brain function and relieving the symptoms of medical conditions can be significantly improved by coating them with carbon nanotubes.

Single-walled carbon nanotubes tend to be produced in polydisperse mixtures with different lengths, diameters and electronic properties. This review article surveys the various techniques that have been developed for producing monodisperse samples from these mixtures. Selective growth techniques are also covered.

A lithographic method using a scanning tunnelling microscope can etch graphene nanoribbons in graphite sheets with nanometre precision. The electronic properties of these ribbons can be engineered by controlling their width and crystallographic orientation.

Ferroelectric oxides have emerged as candidate materials for non-volatile data-storage applications, but they can be difficult to process. Researchers have now used a high-temperature deposition process to fabricate arrays of metal–ferroelectric–metal nanocapacitors with a density of 176 gigabits per square inch.

On the basis of first-principles computer simulations, theorists have predicted that zigzag graphene nanoribbons should display magnetoresistance values that are thousands of times higher than previously reported experimental values, and also should be able to generate highly spin-polarized currents.

A number of optical techniques can produce subwavelength features on surfaces, but they tend to be limited in speed and expensive to implement. Researchers have now shown that a microsphere can be trapped near a surface by a specially shaped laser beam and used as a lens to focus another laser beam that writes subwavelength patterns directly onto the surface.

DNA tiles can be used as a platform to display two different aptamers — short sequences of nucleotides that bind to proteins — with high spatial control, to systematically study the distance dependence of multivalent interactions.

A pilot study in a small number of mice shows that long multiwalled carbon nanotubes introduced into the abdominal cavity can cause asbestos-like pathogenic behaviour. The results suggest the need for further research and caution before introducing nanotube products into the market.

Nanoscale metal/oxide/metal devices that are capable of fast non-volatile switching have been built from platinum and titanium dioxide. The devices could have applications in ultrahigh density memory cells and novel forms of computing.

Coating conventional tungsten and stainless steel electrodes with carbon nanotubes improves their performance in research involving the implantation of electrical devices into the nervous system. The results could have an impact on electrophysiology and the development of brain–machine interfaces.