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[Sandia Lab News]

Vol. 54, No. 18        September 6, 2002
[Sandia National Laboratories]

Albuquerque, New Mexico 87185-0165    ||   Livermore, California 94550-0969
Tonopah, Nevada; Nevada Test Site; Amarillo, Texas

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Sandia president reflects on Sept. 11 Miniaturized lipid biosensor PROTECTing facilities from chem-bio attack CAMU begins on-site treatment of chemical waste landfill material



Personal reflections on September 11: A year later -- by C. Paul Robinson

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It is said that we can never know how momentous the times are until afterward when we pause and look back on them.

Undoubtedly the past year was as momentous as any of us ever want to experience. One year later, the tragedies of September 11 still loom large. Although the sites have been cleared, the memories never will be. Nor will the bereaved ever be the same.

We have had the first taste of victory since that awful day as US soldiers in Afghanistan, with some support from close allies and the Afghans themselves (especially the Northern Alliance), have now routed the Tali- ban from power. We similarly have killed or captured a great many of the Al Qaeda terrorists. Yet a large and unknown number are still out there. The fate of their leader, Osama bin Laden, is also still unknown to us.

President George Bush, in a joint session of Congress, pronounced to world leaders that "you are either with us or you are with the terrorists." That simple maxim is still operating in a powerful way around the world, and enough time has now passed that I believe we know the choices that have been made. Quite surprising, but nonetheless important, we learned that the first leader to call the President and commit his nation to stand with the US was Vladimir Putin, President of the Russian Federation. Our two nations have taken major first steps to try and change the relationship that had persisted for more than five decades, and are examining in serious ways how we can seek a new strategic relationship.

Within Sandia, we have done much to support the Afghan war, as well as to begin the task of building better protections for our citizens here at home. Our work has included both highly classified projects, as well as some that have been revealed to the public. These contributions have been truly significant. I decided not to try and list them here, because I cannot yet talk about many of the most important accomplishments. For those of you who trust my word, please know that Sandia has been leaving a legacy of achievements of which we can all be proud. But, unfortunately, our work is far from over.

One consequence of the September 11 events has been the larger number of government agencies that have sought out Sandia's assistance. This gave testament that we might well have realized our "highest goal" -- adopted well before September 11 -- to become the lab that the nation turns to first for solutions to the problems that threaten peace and freedom for our nation and the world. Indeed, in a larger sense the aftermath of 9/11 has helped us to realize our vision of becoming "true national laboratories" -- supporting every part of the US government that needs the help that our technologies can provide. We have suggested that this is the way our government should operate for the future, and we have championed this view in the impending formation of a new Department of Homeland Security.

We did prove to ourselves, once again, that for research and development to pay the biggest dividends in solving important problems, we must do the work in advance of the need. Our past efforts in strategic planning have never seemed more valuable than now, but the challenge is even greater to be ready to provide relevant technologies for whatever the future brings. We took a major step in recreating our Advanced Concepts Group to focus nearly exclusively on helping us understand how we can continue to contribute to the protection of the nation against terrorist threats.

Our lives have been changed by September 11 in nearly every corner. We deal daily with extra fences and barriers, more security guards, increased airport security, and yet that nagging sense of unease remains. Today, it is still important for each of us to hug our loved ones a little harder, to give thanks for our freedoms a little more fervently, and to continue to use every power within us to help our nation through these troubled times.

Often when I am in Washington, D.C., I get my exercise by walking the Mall between the Capitol building and the Lincoln Memorial. Just above the Lincoln Memorial and across from the Vietnam War Memorial is the Korean War Memorial. As you see the oversized statues of soldiers laboring under the weight of their heavy packs and armaments, they converge on a small wall on which are etched the words "Freedom is not free." This has always been true and will forever be so. The significant difference for all of us since September 11 is that today and every day ahead has now become our day to contribute.

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New miniaturized lipid biosensor has promise of rapidly detecting biological agents

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By Chris Burroughs

Ultrathin double layers of self-assembled fat molecules -- resembling and acting much like soap bubbles -- are at the heart of a new, dime-size biosensor being developed at Sandia by a team of researchers led by Bob Hughes (1744).

The biosensor has the promise of rapidly detecting a variety of biological agents, including viruses, anthrax, and other bacteria, in the field with the same sensitivity and specificity as standard laboratory procedures.

"This biosensor is part of Sandia's biostrategy, driven in one context by our role in defending against the biothreat on the battlefield or at home," says Sandia VP 1000 Al Romig. "One aspect of this defense is prompt and accurate detection of the threat. Our biosensor work, such as what Bob and his team are doing, is directed at such detection. Again, our unique contribution is the application of microsystems, materials science, and information technology to solving a problem in biotechnology with national security relevance."

To this end Bob is adapting electrical impedance detection technology, which he has used for chemical sensors such as the chemiresistor, to biological sensing. Developing biosensors is a natural growth of Sandia's chemiresistor program -- coupling the exquisite sensitivity and selectivity of biological systems to the simple measurement of change in electrical resistance. Sensors with electrical detection, like chemiresistors, are integrated with other electronic components in a microsystem and typically operate at very low power.

The chemiresistor has a base of wirelike electrodes on a specially designed microfabricated circuit. In past experiments Bob focused on volatile organic compounds (VOCs), depositing thin polymer films that detect specific VOCs by absorption. When the VOC molecules appear, the polymer absorbs them, causing the polymer to swell. The swelling changes the electrical resistance that then is measured and recorded, providing information to determine VOC type and concentration present.

Similarly, Bob's new sensor, the lipid chip, has a base of wirelike electronics. However, instead of using polymers as the sensing materials, the new sensor uses organic lipid bilayers -- self-assembled double layers of lipid molecules.

"Scientists have studied lipids, fatlike molecules, for many years and have a good understanding of their characteristics," Bob says. "What is new is integrating them into a rugged biosensor that can detect biological agents."

Tricky work

Working with the lipid bilayers is tricky, Bob says. They are very fragile, like soap bubbles, and have a characteristic that sets them apart from other organic molecules -- their dual oil/water solubility. One part of a lipid molecule is hydrophilic, water-soluble; another part is hydrophobic, oil-soluble. The hydrophilic/hydrophobic characteristics allow the lipids to line up spontaneously (self-assemble). This layer of lipids, about five nanometers thick, is assembled across the electrodes.

"One of the first things we had to do was deal with the fragile nature of lipid bilayers," Bob says. "We had to come up with a way to make them rugged enough to last through experiments and for use in the field."

Bob and his fellow researchers attacked the robustness dilemma by several methods. One uses a thin film of sol-gel to act as a scaffold for the bilayers. The sol-gel scaffold containing the lipid bilayers are placed on top of the electrodes.

Templated sol-gel films are very thin (less than one micron), but very durable -- much like glass, but formed from a jellylike mass of water, alcohol, and metal oxides. The films used in the lipid bilayer sensor were provided by Hongyou Fan and Darren Dunphy in Jeff Brinker's (1846) material science group.

Another method, developed by Darren Branch (1744), uses a hybrid bilayer in which the layer next to the metal electrode is actually not a lipid but an organic silane that attaches to the metal, but still supports the upper lipid monolayer.

'Gated channels'

Another challenge was to create "channels" -- pores formed by proteins in the lipid bilayers that could open and close repeatedly in response to the presence of a specific biological agent. The interaction of the agent with the ion channels in the lipid bilayers is key to the sensor. In the presence of the biological agent, the ion channels can change the electrical impedance of the bilayer by allowing the conduction of ions through the bilayer. In this way the type and concentration of the agent can be identified by a measurement of electrical resistance.

The ion conduction property of these channels, when inserted in lipid bilayers, closely mimics their activity in living cells. The basic structure of the cell wall is a lipid bilayer, although there are many other complex structures also found in the cell wall. Gated ion channel proteins in the cell walls are often involved in exquisitely sensitive chemical detection (often a single molecule can cause the opening or closing of an ion channel).

The study of membrane-bound proteins is an active area of research including protein structure and function in bilayer assemblies and the potential applications in biotechnology, medicine, and biosensing. Sandia is actively involved in this area of research in the Interfacial Bioscience (IBIG) Grand Challenge (Lab News, July 12).

The challenge facing biosensor developers is how to trigger the proteins to recognize when to "open" or "close" their channels in response to a target agent. The ion channels don't work at all if they are not bathed in the relatively fluid lipid bilayer, so it is not possible to use them as sensors in rugged polymer matrixes like the chemiresistors for VOCs.

Use of antibodies

The solution will ultimately be to attach antibodies or other molecular recognition molecules to capture the desired molecules on the ion channels. Bob uses anthrax to explain.

"If, for example, you want to know if anthrax is present, you would attach anthrax antibodies to the ion channel protein in the bilayer," Bob says. "When an anthrax spore comes along, it would attach to the anthrax antibodies connected to the ion channel protein. The protein would change the bilayer's electrical properties in response to the binding."

Bob says the research team has come a long way in the short time it's been working on the lipid bilayer sensor.

"We've accomplished many of our goals," Bob says. "We've been able to build rugged lipid bilayers that last as long as three weeks. We've figured out how to introduce ion channels into the lipid bilayers. We've proven you can make ion channels selective to certain ions in the solution. Now we have to attach antibodies to the ion channels to show we can detect different biological agents. The antibody work may be our most difficult yet." - - Chris Burroughs

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Sandia researches ways to PROTECT facilities from chem/bio terror

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By Nancy Garcia

Preparedness for a chem/bio terrorist attack has been an area of active research at Sandia since well before 9/11.

"The trends in terrorism toward large-scale, high-visibility, high-casualty attacks have been recognized for at least five years," says systems analyst Susanna Gordon (8112).

She has helped lead a five-year program, PROTECT (Program for Response Options and Technology Enhancements for Chemical/Biological Terrorism), that focuses on safeguarding enclosed public facilities such as subway stations and airport terminals. PROTECT aims to demonstrate near-term improvements in response plans, and mid-term improvements using existing or state-of-the-art technology.

PROTECT, a collaboration between Sandia, Argonne National Laboratory, and participating transit authorities, began in 1998, three years after the deadly sarin attack in the Tokyo subway. The chemical-agent release by members of the Aum Shinrikyo cult left 12 dead and 5,500 injured, even though the dispersal through 15 stations was deemed ineffectual, Susanna says.

Due to that precedent and the desire of the Washington Metropolitan Area Transit Authority to work with the labs on this issue, PROTECT initially focused on a possible chemical agent release in a subway.

"We wanted to try to understand how an agent would spread, model it, and then see if reasonable measures could be taken to minimize casualties," says Duane Lindner, deputy director of Advanced Technologies Dept. 8101. "We're discovering there are some things you can start to do today that won't take a lot of money, but will help."

Theatrical smoke and tracer gases have been used to track air flow through transit facilities, such as the Washington Metro.

An integrated, prototype chemical early-warning system has been installed in a Metro station (Lab News, July 28, 2000), where for nearly two years Greg Foltz (8112) has been leading the evaluation of a sensor array for its ability to operate properly in a subway station environment under real-world conditions of rail dust and grime. The sensors have proven capable of fulfilling this need, and a new generation of sensors is being designed for future installations based on the data gathered in this field test.

In the event of a sensor alarm, sensor readings will be analyzed by Argonne-developed software, the Chem/Bio Emergency Management Information System (CB-EMIS), which is designed to map the concentration and direction of a plume. Video images supplement the readings, to confirm whether an attack is taking place. The information, along with recommended response options, is sent first to the Operations Control Center for initial evaluation of the alarm. The control center also receives information with recommendations of "safe zones" and advice to shelter in place or evacuate. If an incident is declared, CB-EMIS provides the same information to the Incident Commander on the scene so emergency personnel will know what they may encounter, and if they should suit up in protective gear before entering.

In addition, Sandia is providing a second software package to the Metro to allow access-controlled, web-based monitoring of the sensor system on a routine basis by Metro maintenance staff and police. This tool displays alarms as well as maintenance faults, and so could be modified to facilitate the rapid deployment of similar sensor systems in other facilities even in the absence of more sophisticated information systems such as CB-EMIS, which may take more time to modify for each facility.

"Nine-eleven really drove home the point for us that a lot of these things are in the operational details," says 8100 Center Director John Vitko.

Since minimizing exposure is key, Susanna adds, "Time really is of the essence. We have found in our analyses that facility response in the first few minutes after an attack is critical."

Emergency response to a chemical incident in the Metro was tested in a field demonstration in December 2001 when the station was closed for the night. A fictitious perpetrator spilled water (simulating an agent) in the station, dashed out and collapsed as a train carrying event "players" pulled up. The plume was modeled by Argonne, and the response of the detectors was simulated by Greg Foltz.

"We are, in part, supposed to determine if the commercial equipment is ready," Greg said. "The technology is here and will clearly improve. We'll be able to integrate next-generation devices as they become available into the operational response system."

The team also plans to implement Sandia's gas-phase ÁChemLab for chemical agent detection in the demonstration program, he says. Two subway systems and an airport authority are now involved in the program.

The airport environment, Greg says, should be more conducive to testing biological detectors, which are being added as the program evolves to include defense against biological agents.

One of the concerns, Susanna points out, is that neither threat -- chemical nor biological -- would necessarily be immediately apparent (unlike fires or earthquakes). It is well known by the public that a biological attack would likely go unnoticed; however, it is less well recognized that some chemical agents can be similarly insidious. For instance, mustard, a chemical weapon of World War I, can be odorless and cause no symptoms for several hours even after exposure to a lethal dose. Detectors that are sensitive to such agents add great value by informing a facility of a threat that may otherwise not be noticed. Detection of faster-acting agents is also quite valuable, because hastening facility response can have an enormous benefit. -- Nancy Garcia

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CAMU begins on-site treatment of soil from Labs' Cold War-era Chemical Waste Landfill

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By Bill Murphy

When the front-end loader last week thudded its first load -- the very first load -- of soil from the Chemical Waste Landfill into the hopper of the low temperature thermal desorption (LTTD) soil treatment unit, members of Sandia's Corrective Action Management Unit (CAMU) team didn't so much as exchange high-fives.

Instead, assistant CAMU task leader Bob Helgesen (6134) simply nodded across the way to the action at the treatment unit and said, almost casually, "That's a historic moment there. It took a lot of years to turn that [LTTD unit] on."

The LTTD unit, brought on site and operated for the CAMU by URS Group Inc., heats contaminated soil to from 400 to 700 degrees F to cook off volatile organic compounds. The special machine, the size of a couple of Peterbuilts with their reefers on, captures the resulting particulates and scrubs and neutralizes (through a catalytic process) the acidic gases produced. The final emission coming out of the unit's exhaust stack contains water vapor, CO2, and CO. The LTTD can handle some 10 tons of contaminated soil per hour. At that rate, says CAMU task lead Mike Irwin (6134), it'll likely be operating on site 20 hours a day for the next three to six months treating soil from the Chemical Waste Landfill.

Sandia's Chemical Waste Landfill, tucked away on a bit less than 2 acres in the far southeast corner of Tech Area 3, was the repository of chemical wastes from 1962 till 1985. In the midst of waging the Cold War, Sandia's -- indeed, the nation's -- attention was focused not so much on environmental concerns as on countering the Soviet nuclear threat. As such, sites like the Chemical Waste Landfill weren't designed or operated with the same level of care for the environment that would apply today. The chemical residue of Sandia's weapons work went into the landfill. Now, some 9,000 cubic yards of bulk soil from the landfill will be treated with the LTTD unit. An additional 24,000+ yards of soil, contaminated with metals, will be treated via soil stabilization. Among organic compounds in the soil are:

"It was a different era, a different world," says ER for Landfills and Test Areas Dept. 6134 Manager David Miller, explaining the origins of the Chemical Waste Landfill and its less-than-enlightened (by 2002 standards) approach to chemical waste control.

In 1989, as the urgencies and expediencies of the Cold War began to be looked at in a different light, attention turned to environmental restoration. Along with several other sites -- the Mixed Waste landfill, the Classified Waste landfill, and others, the Chemical Waste Landfill was identified early on for remediation. After initial soil sampling, it was estimated that to excavate the Chemical Waste Landfill and move the contaminated soil -- some 37,000 cubic yards of it (that's enough dirt to bury a football field 30 or so feet deep) -- would cost in the neighborhood of $280 million. That cost seemed prohibitively expensive, even for as worthy a task as environmental restoration.

Fortunately, at the time these decisions were being made, the US EPA had approved the establishment of an on-site waste management approach -- the CAMU. The CAMU option, which turned out to be perfectly appropriate for Sandia's Chemical Waste Landfill, will have an estimated lifetime cost of $30 million (the lifetime cost is based on 30 years of EPA-mandated oversight of the CAMU facility).

A series of public hearings about the proposed CAMU has indicated strong public support, David says. "They're very much behind us on this."

Mike, who assumed the role of task leader after previous leader Scott Schrader passed away after a long bout with cancer (Lab News, Aug. 11, 2000), says the latest CAMU milestone is the culmination of "a lot of work by a lot of people over the past few years."

Despite the palpable sense of accomplishment and satisfaction among the CAMU team as the switch on the LTTD unit is thrown in earnest for the first time, Mike says there won't be a team celebration just yet.

"We've still got a lot of work to do," he says. -- Bill Murphy

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Last modified: September 18, 2002


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