NANOSCALE OPTICAL FIBERS FOR DETECTION OF BIOTERRORIST AGENTS

In an age when bacterial agents may be intentionally released as method of terrorist attack, there is an increased need for quick diagnostic methods that require limited resources and personnel. Thomas Inzana, the Tyler J. and Frances F. Young Chair of Bacteriology in the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech, has been awarded a grant from the National Institutes of Health to develop such a diagnostic test.

He and his co-investigators, James “Randy” Heflin, a professor in the Department of Physics in the university’s College of Science, and Abey Bandera, a research assistant professor in the veterinary college, are working to develop nanoscale optical fiber biosensor tests, or assays, for detection of Francisella tularensis, Burkholderia mallei, and B. pseudomallei.

Currently, testing involves either the use of cultures in Biosecurity Level-3(BSL-3) laboratories, or since facilities do not have BSL-3 capabilities -- serology or antibody-based testing. Both require extensive materials and training, and the results can take days or weeks.

“This assay will be rugged, portable, inexpensive, and rapid,” said Inzana, who is also the associate vice president for research programs at the university. All of these are critical to minimizing the affect on an intentionally introduced biological weapon.

The increased speed of detection allowed by this new, optical fiber assay will also increase the speed of treatment for those affected, according to Inzana.

The optical fiber is coated with antibodies or DNA that will bind to antigens or DNA in the specimen. When this happens, the light that normally passes through the fiber will be decreased, indicating the presence of a biological agent.

According to Inzana, there are advantages and disadvantages to both. Antigens are more abundant and closer to the surface of the agent, but aren’t always very specific. DNA, however, is very specific, but is less plentiful and resides deep within the cell.

NEW METHOD PRESENTED FOR SYNTHESIS & GROWTH OF CARBON NANOTUBES

Researchers at the Plasma Physics Research Center of Iran's Islamic Azad University devised a new method to improve the synthesis and growth of carbon nanotubes. Carbon nanotubes synthesized in this new way can be used in manufacturing electron emitters and solid devices with high thermal conductivity.

Since 1991, along with the discovery of carbon nanotubes, researchers have always attempted to optimize their production and to utilize them in different industries. Majid Mojtahedzadeh Larijani, one of the researchers, undertook this study with the aim of synthesizing carbon nanotubes by a novel method, which is the growth on the beds with catalytic base by means of ionic bombardment.

The bed used in this study was steel. First in the process, sub-layer underwent surface was treated by argon ionic bombardment at different ion energies and doses. Then by Chemical Vapor Deposition method carbon nanotube growth on bombarded samples using hydrogen and steel gases was accomplished.

The results showed that ion energy and dose in which sub-layer surface turns into fine grains are very appropriate for the growth of dense and adhesive carbon nanotubes. These nanotubes could be applied for manufacturing electron emitters and solid devices with high thermal conductivity in electronics industry.

PARTICLE LENGTH CONTROLS THE TOXICITY AND BIOACTIVITY OF TITANIUM DIOXIDE NANOMATERIAL

Titanium dioxide (TiO2) nanomaterials have considerable beneficial applications varying from additives in paint, paper, plastics and cosmetics to uses in photocatalysts, solar cells and medical materials and devices. It has been established for many years that pigment-grade TiO2 (200 nm sphere) is relatively inert when internalized into a biological model system (in vivo or in vitro).

For this reason, TiO2 nanomaterials are an attractive alternative in applications where biological exposures will occur. Unfortunately, metal oxides on the nanoscale (one dimension <100 nm) may or may not exhibit the same toxic potential as the original material. A further complicating issue is the effect of modifying or engineering of the nanomaterial to be structurally and geometrically different from the original material. TiO2 nanospheres, short (<5 µm) and long (>15 µm) nanobelts were synthesized, characterized and tested for biological activity using primary murine alveolar macrophages and in vivo in mice. This study demonstrates that alteration of anatase TiO2 nanomaterial into a fibre structure of greater than 15 µm creates a highly toxic particle and initiates an inflammatory response by alveolar macrophages.

These fibre-shaped nanomaterials induced inflammasome activation and release of inflammatory cytokines through a cathepsin B-mediated mechanism. Consequently, long TiO2 nanobelts interact with lung macrophages in a manner very similar to asbestos or silica.

These observations suggest that any modification of a nanomaterial, resulting in a wire, fibre, belt or tube, be tested for pathogenic potential.

LIGHTWEIGHT POLYMER COMPOSITE MATERIALS IN ROAD NOW

CSIRO (Commonwealth Scientific and Industrial Research Organization, Australia's national science agency) researchers have set themselves the goal of producing a new generation of super-strong, lightweight polymer composite materials for use in aircraft, road vehicles, trains and ferries.

Aerospace manufacturers have already embraced weight-reducing composites, but until recently they were used in only a limited range of applications. However, in the new generation of aircraft being developed and built today, polymer composites are used extensively.

A team led by Dr Stuart Bateman at CSIRO Materials Science and Engineering is designing and testing even lighter and stronger polymer composites that will out-perform the conventional materials currently used in the transportation sector.

Composites with improved mechanical properties allow greater design flexibility. Nano-technology provides the scope to improve the mechanical performance of conventional composite materials.

These kind of improved properties are created by dispersing low concentrations of specially chosen additives within the polymer matrix. By this means the CSIRO team is producing polymers with unprecedented properties, such as strength, stiffness, impact resistance, fire resistance, and heat reflectance.

The design of the additive and controlling its dispersion are both crucial to producing the mix of properties required.

Some of the new functional additives are effective at trace concentrations, below one per cent. This low content is a bonus because it avoids unwanted changes in the material's processing ability and end properties such as surface finish, while still improving mechanical properties.

Many traditional halogenated compounds are falling out of favor with health and environmental agencies, creating a pressing need for alternatives. Super-light composites with enhanced flame retardant properties are expected to find uses in transportation, infrastructure and in defence applications.