A major concern in microbiology is to determine whether a bacterium is dead or alive. This crucial question has major consequences in food industry, water supply or health care. While culture-based tests can determine whether bacteria can proliferate and form colonies, these tests are time-consuming and work poorly with certain slow-growing or non-culturable bacteria. They are not suitable for applications where real-time results are needed, e.g. in industrial manufacturing or food processing. A team of scientists in France has now discovered that living and dead cells can be discriminated with a nanotechnology technique on the basis of their cell wall nanomechanical properties.
A recent report gives an overview of how five jurisdictions (US, UK, EU, Australia and Canada) reacted to the recent emergence of nanotechnology-based products in the marketplace and it describes how this triggered activities in three domains: (a) public and stakeholder debate, (b) development of initial policy options, and (c) the management of regulatory development in a situation of scarce data. The bulk of the report describes the current situation (up to March 2009) in the five jurisdictions and this part doesn't contain information that hasn't already been covered elsewhere. In analyzing this data, however, the authors make some interesting observations and attempt to develop a set of six key regulatory governance principles that they propose for consideration by regulators.
In a previous Nanowerk Spotlight we have reported about the work of Chinese scientists who demonstrated that a sheet of carbon nanotube (CNT) thin film could be a practical magnet-free loudspeaker simply by applying an audio frequency current through it . The team has now reported that their CNT films can also work as an incandescent display, driven by a simple addressing circuit with response times faster than that of liquid crystal displays (LCDs). At the same time, the incandescent light of the CNT film is almost nonpolarized, and will not have the viewing-angle problem of LCDs. The CNT films in vacuum can be heated to incandescence and cooled down in about 1 millisecond by turning on and shutting off the heating voltage.
The prospect of stretchable electronics opens some exciting possibilities - for instance, think about artificial skin with an integrated, stretchable touchscreen display. To get there, researchers have begun developing elastic electrical wiring that is both highly conductive and highly stretchable. Currently existing stretchable materials do already exhibit excellent conductivity and mechanical stretchability but they have one major disadvantage: their manufacturing processes are not readily scalable, which means it is difficult or cost-prohibitive to apply them to large-area electronics. A research team in Japan has now successfully fabricated, for the first time, novel elastic conductors that can be directly patterned by printing processes. This novel, printable elastic conductor comprises single-walled carbon nanotubes uniformly dispersed in a highly elastic fluorinated copolymer rubber.
Proteins that bind to specific sites of DNA are essential to all biological functions of DNA. These DNA-binding proteins include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging in the cell nucleus. Developing methods to precisely determine the locations and occupancy of DNA-binding proteins is instrumental to scientists' understanding of cellular processes like gene expression and regulation. Motivated by the desire to overcome some of the inherent limitations of existing biochemical techniques for mapping protein binding sites on DNA, scientists at UCLA have now demonstrated the viability of a single molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots, allowing multicolor, nanometer-resolution localization.
Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents. These materials are also known as molecular sieve - they contain tiny pores of a precise and uniform size that are useful as adsorbent for gases and liquids. Due to these characteristics, zeolite has found wide applications in adsorption, catalysis, and the removal of heavy metal ions from industrial wastewaters. The zeolites commonly used to remove heavy metal ions from industrial effluent are in the form of fine powders and must be recovered by solid-liquid separation subsequent to the purification process. Although the separation is possible for single-phase liquid or gas detoxification processes, the practical application of fine zeolite powders to complex multiphase systems is rather limited. Researchers in Canda have now devised a new technology to separate the spent sorbent powders from treated streams. This could extend the application of zeolites to a much wider range of systems.
One of the key issues in building implantable neural interfaces is the guidance of axons, the individual nerve fibers that act as the primary transmission lines of the nervous system. The ability to control the connections between neurons by guiding their axons on a chip surface offers several advantages. Among them is the possibility to address axons from different types of neurons, e.g., motor neurons from sensory neurons. This is a prerequisite condition for bidirectional neural implants such as brain machine interfaces. Axonal guidance has been achieved before, and there are various chemical and topographical modification techniques to do so. However, scientists only managed to control the orientation of the nerve fibers. In new work, a Swedish team shows that it is possible to impose a growth direction at a specific location on a substrate, something which is very important for neural chip construction for example. The first application for this research would be in neural network design.
New work at the University of Arkansas has, for the very first time, demonstrated that Raman spectroscopy can be used to detect and monitor circulating carbon nanotubes in vivo and in real time. These findings could have a significant impact on the knowledge of how nanomaterials interact with living biological systems. Carbon nanotubes can be used for various advanced bio-medical applications. Before any clinical application of nanoparticles, it is imperative to determine critical in vivo parameters, namely pharmacological profiles including nanoparticle clearance rate from the circulation and their biodistribution in various tissue and organs. Until now, their distribution was only monitored by collecting samples after various time intervals, but this new research shows the ability of monitoring their concentration in vivo and in real time, while the animal is alive. Moreover, this work can be extended to the detection of circulating cancer cells that have been tagged by carbon nanotubes.