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Showing Spotlights 1089 - 1096 of 2050 in category (newest first):

 

Titanium dioxide powers light-driven micro- and nanomotors

microfireworksFor nanotechnology researchers, movement at the nanoscale is a challenging problem and there is much to be learned from nature's motor systems. There are various approaches to creating self-propelled micro- and nanosized motors and one promising approach rests on catalytic conversion of chemical to mechanical energy - a process that is ubiquitous in biology, powering such important and diverse processes as cell division, skeletal muscle movement, protein synthesis, and transport of cargo within cells. Self-propelled motion of synthetic materials can be useful in applications such as bottom-up assembly of structures, pattern formation, drug delivery at specific locations, etc. Researchers have now presented a novel and versatile light-driven catalytic micromotor system, which is the cleanest and simplest of its kind.

Posted: Jun 2nd, 2010

Biorefinery concept shows a way out of a world dominated by petrochemicals

algae-FuelDeveloping chemicals, molecular precursors, and industrial products from petroleum resources is a conventional practice. Plastics, detergents, even pharmaceuticals are derived from petrochemicals. With an increasing focus on the economic and environmental issues associated with the processing of petroleum-based chemicals, scientists are seeking for alternative routes to develop molecules from naturally available plant or crop-based raw materials. Particularly interesting for the fields of nanotechnology is the design and development of soft nanomaterials from renewable sources. Generating these materials from renewable resources could have a significant impact on production technologies and economies.

Posted: Jun 1st, 2010

Bottom-up fabrication of carbon nanosystems by trapping single metal atoms

graphene_sheetAmong the various production methods for carbon nanotubes and graphene, currently only chemical vapor deposition techniques demonstrate a significant opportunity for mass production of CNT material. Using the CVD process, which is based on the catalytic action of metals, manufacturers can combine a metal catalyst such as iron with reaction gases such as hydrogen to form carbon nanotubes inside a high-temperature furnace. In order to optimize the synthesis process, a detailed understanding of the interaction between nanotubes or graphene and metal atoms is required - something that has been missing so far. Researchers in France have now shown that it is possible to create atomic-scale defects in carbon nanotubes and in graphene in preselected positions with a focused electron beam and to use these defects as trapping centers for foreign atoms.

Posted: May 31st, 2010

Microbubble scavengers can remove carbon nanotubes from the body

microbubble_cnt_scavengerCarbon nanotubes' interesting structural, chemical, electrical, and optical properties are explored by numerous nanomedicine research groups around the world with the goal of drastically improving performance and efficacy of biological detection, imaging, and therapy applications. In many of these envisaged applications, CNTs would be deliberately injected or implanted in the body, for instance as intercellular molecular delivery vehicles. One of the issues researchers have been exploring is how - once the primary role of CNTs in a therapeutic application is fulfilled - they can promote the rapid removal of CNTs from the body, or the dispersal of aggregated clusters to sub-micron size in order to mitigate the harmful effects. Researchers in India have now demonstrated a novel, optical tweezers based approach to scavenge CNTs from biological fluids such as blood.

Posted: May 27th, 2010

New findings about the activity of graphene oxide sheets at interfaces

graphene_oxideGraphite oxide sheet, now being named graphene oxide - a compound of carbon, oxygen, and hydrogen obtained by treating graphite with strong oxidizers - has attracted substantial interest as a possible intermediate for the manufacture of graphene. It has been largely viewed as hydrophilic - having a strong affinity for water illustrated by its excellent colloidal stability in water. In what should help to better understand and improve the solution processing of graphite oxide-based graphene materials and open up opportunities to design new functional graphite oxide-based hybrid materials, researchers have now reported that graphite oxide is amphiphilic - possessing both hydrophilic and lipophilic (fat-liking) properties - and can adsorb onto air-water, oil-water and solid-water interfaces.

Posted: May 26th, 2010

Novel aberration correction opens up new perspectives for optical micromanipulation

aberration_correctionAberrations in optical systems, which leads to blurring of the image, and their elimination using adaptive optics have been studied in astronomical research for quite a long time. Aberrations occur when light from one point of an object after transmission through the optical system does not converge into a single point. The complicated part in correcting this error usually lies in identifying the aberrations that need to be eliminated from the system. With the emergence of nanoscale applications, aberrations in modern microscopy have become a severe limitation on the optimal performance in imaging, nanosurgery, nanofabrication and micromanipulation, just to name a few. Researchers have now demonstrated a powerful method for aberration correction with a simple implementation that typically requires minimal changes in the particular geometry.

Posted: May 25th, 2010

Excessive use of toxic materials in medical nanotechnology could be avoided

nanoparticlesMetal nanomaterials are often synthesized using the toxic reagent formaldehyde at concentrations thousands of times higher than necessary. Many of these same nanomaterials are being investigated for use in cancer treatment - however, there is a risk that they could do more harm than good. The large excess of formaldehyde that is used originates from methods developed 100 years ago. Because these methods work well, they have stood the test of time. By better understanding the role that formaldehyde plays in nanomaterial synthesis it will become possible to reduce or eliminate this toxic reagent. By eliminating formaldehyde it will become safer to prepare these nanomaterials and safer to use them in cancer treatment.

Posted: May 24th, 2010

Stretchy and conductive nanotechnology composite for robot skin and strain sensors

nanotube_forestElectrically conductive composite materials capable of substantial elastic stretch and bending - conductive rubbers - is an industrially important field. The composites are needed for such applications as smart clothing, flexible displays, stretchable circuits, strain gauges, implantable devices, high-stroke microelectromechanical systems, and actuators. A variety of approaches involving carbon nanotubes and elastic polymers have been suggested for the fabrication of conductive elastic composites. Various studies indicated that high loading of CNTs or other conductive additives into the polymer was necessary to obtain a highly conducting composite. A research team has now demonstrated that a combination of high stretchability and high electrical conductivity can be obtained for composites prepared from three-dimensional CNT structures.

Posted: May 21st, 2010