The 2007 NASA Tech Briefs National Nano Engineering Conference (NNEC), to be held November 14-15 at the Boston Marriott Copley Place, is produced for design engineers who want to know what’s real, what’s close, and what might be coming in the world of nanotechnology. The NNEC will help you keep pace with the engineering and technology innovations behind the latest nanotech breakthroughs. Included will be technical presentations and exhibits from companies leading the nanotech industry in application areas such as biomedical, electronics, advanced materials, energy and the environment, and business. You’ll also find networking opportunities, and the expert insight you’ll need to stay ahead of the small-tech curve.

The NNEC also features the presentation of the Nanotech Briefs® Nano 50™ Awards. This year’s third annual awards recognize the top 50 innovators, technologies, and products that have significantly impacted — or are expected to impact — the state of the art in nanotechnology. The Nano 50 will be presented at a special awards dinner held on Wednesday, November 14. For a complete list of 2007 winners, visit here .

A number of this year’s Nano 50 winners will present their award-winning technologies in panel sessions, including those featured here. Visit here for more information and to register for the NNEC.

Carbon Nanotubes Detect Chemical Vapors

The U.S. Naval Research Laboratory (NRL) is developing a chemical sensor technology based on single-walled carbon nanotubes (SWNTs). Dr. Eric Snow is head of the Electronic Materials Branch at the NRL, and is a 2007 Nano 50 winner in the Innovator category.

SWNTs possess many unique properties that make them well suited for the direct electronic detection of trace chemical vapors. These properties include the structure of SWNTs in which every atom is a surface atom. This infinite surface-to-volume ratio produces a high sensitivity to its local chemical environment. SWNTs also exhibit near-ballistic electron transport along the nanotube axis, which provides an efficient electrical conduit to transmit changes in electrical properties caused by the presence of a molecular adsorbate. Finally, the chemically inert graphitic structure of SWNTs provides reliable operation in harsh environments.

But in order to take advantage of these properties, there are a number of technical challenges that must be overcome before one can incorporate SWNTs into a commercial chemical detection system. These include the development of an inexpensive, high-yield fabrication procedure; reduction of 1/f noise; optimization of the electronic transduction mechanism; and providing chemical specificity. Dr. Snow’s presentation will describe the NRL’s approach to addressing each of these issues. He also will provide an update on the NRL’s progress toward developing a SWNT-based vapor detection system for trace levels of toxic industrial chemicals, chemical warfare agents, and explosives.

Learn more about the Naval Research Laboratory’s work in SWNT-based chemical detection sensors from Dr. Snow during the Nanodevice Fabrication Session at 2:00 pm on Wednesday, November 14.

Helium Ion Microscopy

Helium Ion Microscopy (HIM) is a new, potentially revolutionary imaging and particle beam measurement methodology. The first commercial HIM has been installed at the National Institute of Standards and Technology in Maryland. Dr. Michael T. Postek is the Chief of the Precision Engineering Division and Program Manager of the Nanomanufacturing Program in the Manufacturing Engineering Laboratory (MEL) at NIST, and is a 2007 Nano 50 winner in the Innovator category. A research program within MEL will study the imaging mechanisms, modeling, analytical capabilities, and uncertainties regarding dimensional measurements made with this microscope.

This methodology presents an potentially revolutionary approach to measurements that has several potential advantages over the traditional scanning electron microscope (SEM) currently in use in research and manufacturing facilities across the world. The HIM is unique but also complimentary to the traditional SEM. Due to the very high source brightness, and the shorter wavelength of the helium ions, it is theoretically possible to focus the helium ion beam into a smaller probe size relative to that of an electron beam of an SEM, so higher resolution is possible. In an SEM, an electron beam interacts with the sample and a variety of signals is generated, collected, and imaged. This interaction zone may be quite large, depending upon the electron energy and sample material. Conversely, when the helium ion beam interacts with the sample, it does not have as large an excitation volume and thus, the image collected contains more surface-related information and can potentially provide atomic resolution images on a wide range of materials.

The current suite of HIM detectors can provide information on topographic, material, crystallographic, and electrical properties of the sample. Compared to an SEM, the secondary electron yield is quite high, allowing for imaging at extremely low beam currents. The relatively low mass of the helium ion, in contrast to other ion sources such as gallium, results in no discernable damage to the sample.

Learn more about NIST’s Helium Ion Microscope from Dr. Postek in the Advances in Imaging/Microscopy Session at 11:00 am on Thursday, November 15.

Novel Method for Creating Carbon Nanotubes

Dr. Jeanette Benavides, a researcher at NASA’s Goddard Space Flight Center in Maryland, has developed a simpler, safer, and much less costly process to make single-walled carbon nanotubes (SWCNTs) without a metal catalyst. For her discovery, Dr. Benavides is a Nano 50 winner in the Technology category.

Nanotubes can be either semiconductors or conductors, depending on how they are made. The key to Dr. Benavides’ process was understanding how to produce bundles of nanotubes without using metal, which reduced the costs tremendously and made a better-quality product.

The improved production process could increase the prevalence of carbon nanotube technology in many areas, including medical applications such as portable/field equipment, implantable biosensors, artificial limbs and organs, and drug delivery; miniature and consumer electronics; research instruments (e.g., microscopy); fuel cells; radiation shielding; and innovative polymers for a wide range of applications.

Earlier this year, NASA Goddard licensed the patented technique for manufacturing the SWCNTs to Idaho Space Materials (ISM) in Boise. Now the carbon nanotubes based on this creation process are being used by researchers and companies working on new materials with ceramics and polymers.

The steps toward the discovery of this process will be discussed along with a description of the process and properties of the single-walled carbon nanotubes produced. These properties include solubility in acetone and alcohol and assembly into three-dimensional structures. Potential applications will also be discussed.

Learn more about Dr. Benavides’ process for making SWCNTs in the Nanomaterial Fabrication/Manufacturing Session at 11:15 am on Wednesday, November 14.

Nanotube Energy Storage Device

Carbon nanotubes have an important place in nanotechnology. From nanoelectronics to high-strength composites, there is a large effort worldwide in research and development of these materials for uses such as energy storage. Dr. Pulickel Ajayan, Professor of Materials Science and Engineering at Rensselaer Polytechnic Institute (RPI), is a Nano 50 winner in the Innovator category, and is part of an RPI team that has developed a new energy storage device that easily could be mistaken for a simple sheet of black paper.

The nanoengineered battery is lightweight, ultra-thin, completely flexible, and geared toward meeting the trickiest design and energy requirements of tomorrow’s gadgets, implantable medical equipment, and transportation vehicles. It can function in temperatures up to 300°F and down to 100 below zero, is completely integrated, and can be printed like paper. Another key feature is the capability to use human blood or sweat to help power the battery. More than 90% of the device is made up of cellulose, the same plant cells used in paper.

Dr. Ajayan and his team infused this paper with aligned carbon nanotubes, which give the device its black color. The nanotubes act as electrodes and allow the storage devices to conduct electricity. The device can provide the long, steady power output comparable to a conventional battery, as well as a supercapacitor’s quick burst of high energy. It also can be rolled, twisted, folded, or cut into any number of shapes with no loss of mechanical integrity or efficiency. The paper batteries can also be stacked, like a ream of printer paper, to boost the total power output.

The components are molecularly attached to each other: the carbon nanotube print is embedded in the paper, and the electrolyte is soaked into the paper. The end result is a device that looks, feels, and weighs the same as paper. Along with use in small handheld electronics, the paper batteries’ light weight could make them ideal for use in automobiles, aircraft, and even boats. The paper also could be molded into different shapes, such as a car door, which would enable important new engineering innovations.

Learn more about RPI’s nanotube energy storage technology from Dr. Ajayan in the CNT Advances for Nanoelectronics Session at 3:45 pm on Wednesday, November 14.

Nanoparticle Drug Delivery

Dr. Omid Farokhzad is an assistant professor at Harvard Medical School and a practicing physician in the Department of Anesthesiology at Brigham and Women’s Hospital (BWH). Dr. Farokhzad is also a Nano 50 winner in the Innovator category for his work in nanoparticle drug delivery. Dr. Farokhzad and his team have custom designed tiny nanoparticles so they home in on dangerous prostate cancer cells, and then enter the cells to deliver a lethal dose of chemotherapy. Normal, healthy cells remain unscathed.

The experiments were done first on cells growing in laboratory dishes, and then on mice bearing human prostate tumors. The tumors shrank dramatically, and all of the treated mice survived the study, in contrast to the untreated control animals. “A single injection of our nanoparticles completely eradicated the tumors in five of the seven treated animals, and the remaining animals also had significant tumor reduction, compared to the controls,” said Dr. Farokhzad.

The team tailor-made tiny sponge-like nanoparticles laced with the drug docetaxel. The particles are specifically designed to dissolve in a cell’s internal fluids, releasing the anti-cancer drug either rapidly or slowly, depending on what is needed. These nanoparticles were purposely made from materials that are familiar, and approved for medical applications by the U.S. Food and Drug Administration. To make sure only the correct cells are hit, the nanoparticles are “decorated” on the outside with targeting molecules called aptamers, tiny chunks of genetic material (RNA). Like homing devices, the aptamers specifically recognize the surface molecules on cancer cells, while avoiding normal cells. In other words, the bus is

driven to the correct depot.

The team chose nanoparticles as drug delivery vehicles because they are so small that living cells readily swallow them when they arrive at the cell’s surface. Particles larger than 200 nanometers are less likely to get swallowed through a cell’s membrane. The team created particles that are about 150 nanometers in size.

Learn more about nanoparticle drug delivery from Dr. Farokhzad in the Pharmaceuticals/Drug Delivery Session at 9:00 am on Thursday, November 15.


NASA Tech Briefs Magazine

This article first appeared in the October, 2007 issue of NASA Tech Briefs Magazine.

Read more articles from the archives here.