Sandia researchers, using off-the-shelf equipment in a chemistry lab, have been working on ways to improve amputeesí control over prosthetics with direct help from their own nervous system.
Organic materials chemist Shawn Dirk (1821) focuses a projector during work on neural interfaces, which are aimed at improving amputeesí control over prosthetics with direct help from their own nervous systems. Focusing prior to exposing polymers ensures that researchers pattern the desired feature sizes for the interfaces. (Photo by Randy Montoya)
Organic materials chemist Shawn Dirk (1821), robotics engineer Steve Buerger (6533), and fellow researchers are creating biocompatible interface scaffolds. The goal is improved prosthetics with flexible nerve-to-nerve or nerve-to-muscle interfaces through which transected nerves can grow, putting small groups of nerve fibers in close contact to electrode sites connected to separate, implanted electronics.
Neural interfaces operate where the nervous system and an artificial device intersect. Interfaces can monitor nerve signals or provide inputs to let amputees control prosthetic devices by direct neural signals, the same way they would control parts of their own body.
Sandia’s research focuses on biomaterials and peripheral nerves at the interface site. The idea is to match material properties to nerve fibers with flexible, conductive materials that are biocompatible so they can integrate with nerve bundles.
“There are a lot of knobs we can turn to get the material properties to match those of the nerves,” Shawn says.
Researchers are looking at flexible conducting electrode materials using thin evaporated metal or patterned multiwalled carbon nanotubes.
The work is in the early stages and it would be years before such materials could be used. Studies must confirm they function as needed; then they would face a lengthy Food and Drug Administration approval process.
But the need is there. The Amputee Coalition estimates 2 million people in the United States are living with limb loss. The Congressional Research Service reports more than 1,600 amputations involving US troops between 2001 and 2010, more than 1,400 of them associated with the fighting in Iraq and Afghanistan. Most were major limb amputations.
Before joining Sandia, Steve worked with a research group at MIT developing biomedical robots, including prosthetics. Sandia’s robotics group was developing prosthetics before his arrival as part of DOE-sponsored nonproliferation projects dealing with humanitarian programs.
The crux of the problem
Robotics approached the problem from a technical point of view, looking at improving implantable and wearable neural interface electronics. But Steve says that didn’t deal with the central issue of interfacing with nerves.
Working with Shawn’s team “goes after the crux of the problem,” he says.
The challenges are numerous. Interfaces must be structured so nerve fibers can grow through. They must be mechanically compatible so they don’t harm the nervous system or surrounding tissues, and biocompatible to integrate with tissue and promote nerve fiber growth. They also must incorporate conductivity to allow electrode sites to connect with external circuitry, and electrical properties must be tuned to transmit neural signals.
Shawn presented a paper on potential neural interface materials at the recent Boston meeting of the Materials Research Society, describing Sandia’s work in collaboration with the University of New Mexico and MD Anderson Cancer Center in Houston. Co-authors are Steve, UNM assistant professor Elizabeth Hedberg-Dirk, UNM graduate student and Sandia contractor Kirsten Cicotte, and MD Anderson’s Patrick Lin and Gregory Reece.
The researchers began with a technique first patented in 1902 called electrospinning, which produces nonwoven fiber mats by applying a high-voltage field between the tip of a syringe filled with a polymer solution and a collection mat. Tip diameter and solution viscosity control fiber size.
Collaborating with UNM’s Center for Biomedical Engineering and department of chemical engineering, Sandia researchers worked with polymers that are liquid at room temperature. Electrospinning these liquid polymers does not result in fiber formation, and the results are sort of like water pooling on a flat surface. To remedy the lack of fiber formation, they electrospun the material onto a heated plate, initiating a chemical reaction to crosslink the polymer fibers as they were formed, Shawn says. Researchers were able to tune the conductivity of the final composite with the addition of multiwalled carbon nanotubes.
The team electrospun scaffolds with two types of material — PBF, or poly(butylene fumarate), a polymer developed at UNM and Sandia for tissue engineering, and PDMS, or poly(dimethylsiloxane).
PBF is a biocompatible material that’s biodegradable so the porous scaffold would disintegrate, leaving the contacts behind. PDMS is a biocompatible caulk-like material that is not biodegradable, meaning the scaffold would remain. Electrodes on one side of the materials made them conductive.
Patents applied for
Sandia’s work was done under a late-start Laboratory Directed Research & Development (LDRD) project in 2010; afterward, the researchers partnered with MD Anderson for implant tests. Sandia and MD Anderson now are seeking funding to continue the project, Shawn says.
Steve says they are using their proof-of-concept work to obtain third-party funding “so we can bring this technology closer to something that will help our wounded warriors, amputees and victims of peripheral nerve injury.”
Sandia and UNM have applied for a patent on the scaffold technique. The Labs also filed two separate provisional patent applications, one in partnership with MD Anderson and the other with UNM, and expects to submit full applications this year.
The MD Anderson collaboration came about because then-Sandian Dick Fate, an MD Anderson patient who’d lost his left leg to cancer, thought the hospital and the Labs were a natural match. He brokered an invitation from Sandia to the hospital, which led to the eventual partnership.
Dick, who retired in 2010, views the debilitating effect of rising health care costs on the nation’s economy as a defense- and security-related issue.
“To me it seems like such a logical match, the best engineering lab in the country working with the best medical research institution in the country to solve some of these big problems that are nearly driving this country bankrupt,” he says.
After Sandia researchers came up with interface materials, MD Anderson surgeons sutured the scaffolds into legs of rats between a transected peroneal nerve. After three to four weeks, the interfaces were evaluated.
Getting the feature size down
Samples fabricated from PBF turned out to be too thick and not porous enough for good nerve penetration through the scaffold, Shawn says. PDMS was more promising, with histology showing the nerve cells were beginning to penetrate the scaffold. The thickness of the electrospun mats, about 100 microns, were appropriate, Shawn says, but weren’t porous enough and the pore pattern wasn’t controlled.
The team’s search for a different technique to create the porous substrates led to projection microstereolithography, developed at the University of Illinois Urbana Champaign as an inexpensive classroom outreach tool. It couples a computer with a PowerPoint image to a projector whose lens is focused on a mirror that reflects into a beaker containing a solution.
Sandia researchers set up the system with a Dell laptop and an Epson projector. Shawn says they initially tried using a mirror and a 3X magnifying glass, but abandoned that because it produced too much distortion. They now use the magnifying glass to focus UV light onto the PDMS-coated silicon wafer to form thin porous membranes.
While the lithography technique is not new, “we developed new materials that can be used as biocompatible photo-crosslinkable polymers,” Shawn says.
The technique allowed the team to create a regular array of holes and to pattern holes as small as 79 microns. Now researchers are using other equipment to create more controlled features.“It’s exciting because we’re getting the feature size down close to what is needed,” Steve says. - Sue Major Holmes
Nearly two-thirds of the oil we use comes from wells drilled using polycrystalline diamond compact (PDC) bits, originally developed nearly 30 years ago to lower the cost of geothermal drilling. A recent demonstration project by Sandia and the US Navy brings the technology full-circle, potentially helping geothermal drillers reap the benefit of the original technology, as well as decades of subsequent oil and gas industry R&D.
Elton Wright (6916) shows a torsional spring thatís used to simulate the rotational vibration of the drill string in a Sandia experiment. (Photo by Randy Montoya)
Sandia and the Navy’s Geothermal Program Office (USN GPO) conducted the Phase One demonstration tests as part of a geothermal resources evaluation at the Chocolate Mountains Aerial Gunnery Range (CMAGR) in Imperial Valley, Calif.
Sandia has a long history of involvement with both geothermal and drill bit technology development. Three decades ago Sandia geothermal researchers played a large role in the development of PCDs for drilling applications. That work focused on resolving material issues, laboratory testing, and development of data and design codes that now form the basis of the bit industry. Since then, Sandia has received geothermal funding to improve PCD bits. The work was intended to increase access to geothermal resources in the continental US by enabling the drilling of deep, hot resources in hard, basement rock formations.
Geothermal drilling more demanding
Because oil and gas drilling is easier than geothermal drilling, PCDs were appropriated for oil and gas resources.
“Because of the greater challenges associated with geothermal drilling, drilling for oil and gas has been traditionally easier than drilling for geothermal resources,” says principal investigator David Raymond (6916).
“Oil and gas drilling is normally done in softer and less-fractured rock, resulting in fewer problems with fluid circulation to remove debris and cool the bit. Oil and gas drilling also doesn’t usually involve the higher temperatures that geothermal wells exhibit.”
But as the oil and gas industry looks for new sustained resources in deeper reservoirs, it encounters more difficult drilling conditions similar to those found in geothermal drilling.
“Oil and gas drilling must now go deeper into the ground, into harder and sometimes fractured rock types, and in hotter environments,” says David.
He says geothermal resources are typically associated with igneous and metamorphic rocks, which are harder than the sedimentary rocks through which oil and gas wells are drilled. Igneous and metamorphic rocks also can contain large amounts of abrasives such as quartz, which can quickly damage drill bits through vibration and accelerated wear. These types of rocks are also often fractured, which can change the impact loading on drills, causing further drill damage.
“Drilling for geothermal energy is still the most difficult drilling on a cost-per-foot basis,” says David. “You have to go through the hardest rock, sometimes at high temperatures and pressures. The DOE vision for advanced geothermal development is to drill to great depths, up to 30,000 feet, to access heat for geothermal.”
Oil/ gas industry has a bigger appetite for risk
In addition to technical problems, the economic risk profile for oil and gas wells is different. Because many more oil and gas wells are drilled per year, the oil and gas industry has the resources and risk appetite for significant research and testing to improve the ability to drill under increasingly difficult conditions.
The geothermal industry advances far more slowly than the oil and gas industry. Because geothermal drillers create only a small number of new wells each year, the drilling service industry finds it difficult and expensive to support innovation, when each well represents a substantial risk.
The Sandia/Navy demonstration project called for a test hole to evaluate geothermal resources in the Camp Billy Machen/Hot Mineral Spa region that would have been otherwise undetectable at the surface. The basement rock at the Chocolate Mountains includes granite and andesite, typical formations encountered during geothermal drilling.
A key part of the demonstration project was to test and evaluate PDC bits and related technologies in a real-world drilling environment. Sandia worked with PDC bit manufacturer NOV Reed Hycalog to specify PDC bit solutions. NOV provided both commercially available drill bits and knowledgeable on-site personnel to counsel the drilling contractor during drilling runs.
Sandia worked with the USN GPO drilling contractor Barbour Well in evaluating the subject drilling technologies during the production drilling process.
Sandia, Prime Core, and the Barbour Well mud logging company Prospect Geotech fielded instrumentation on the Barbour rig to allow monitoring of drill rig during the drilling process.
In the tests, two test bits drilled 1,291 feet of the overall well depth of 3,000 feet. The two bits were in the well just over four days, penetrating approximately 30 feet per hour throughout their drilling interval, an improvement of nearly a factor of 3 over the standard roller bit that was being used. The downhole data was successfully retrieved from both bits and downloaded for subsequent analysis.
Phase two will evaluate drill performance
The collected data will be compiled and analyzed to provide insight into bit performance at the site.
In a planned second phase of the project, Sandia will continue work with Reed Hycalog to evaluate drill performance and improve the bit design and materials for subsequent demonstration.
Sandia personnel include David Raymond, Steve Knudsen (6916), Jiann Su (6916), Dennis King (6916) and Keith Barrett (6916). Elton Wright (06916), a technologist in the geothermal research department, has supported laboratory testing of PCD technology for nearly two decades.
Cooperative work between the USN GPO and Sandia was covered by a Memorandum of Understanding between the Department of Defense and the Department of Energy addressing collaborative development of renewable energy resources.
Phase one and two of this work are funded an ARRA project, “Technology Development and Field Trials of EGS Drilling Systems,” under the supervision of DOE. -- Stephanie Holinka
By Nancy Salem
Sandia spent close to $1 billion overall on the procurement of goods and services in fiscal year 2011, and small businesses across the nation were awarded more than half those dollars, $540 million or 59 percent, according to the Lab’s latest economic impact report.
Click image at aleft to download a full PDF version of the economic impact report
The 2011 Sandia National Laboratories Economic Impact on the State of New Mexico report breaks down Sandia’s spending and spotlights its role in the state’s economy. The annual report shows New Mexico companies secured nearly $400 million in business with Sandia in fiscal year 2011.
“Sandia National Laboratories is committed to strengthening our relationships with the New Mexico business community and, in particular, to be a strong advocate for New Mexico’s diverse, small business suppliers,” says Don Devoti, manager of Small Business Utilization Dept. 10222.
Sandia reaches out to local businesses through a variety of programs. It holds public forums with the supplier community and civic leaders to discuss contracting opportunities, and lists contracts on its Business Opportunities website, http://supplier.sandia.gov/
opportunities/selection.aspx. It supplies small business owners with information on doing business with Sandia and seeks qualified potential suppliers.
“Sandia’s Small Business team and all of the Procurement organization work diligently to seek out qualified, capable small businesses that Sandia can partner with to achieve our national security mission,” Don says. “We continue to make ourselves available to the community, to be as transparent as possible with our procurement processes, to provide maximum contracting opportunities to small businesses, and to be creative and innovative in our work approaches.”
Here are some numbers showing Sandia’s overall economic impact in 2011:
• $1.4 billion was spent on labor and non-contract-related payments.
• $921 million went to contract-related payments.
• $65.6 million was sent to the state of New Mexico for corporate taxes.
• $73 million was spent through procurement card purchases, in which Sandia employees use credit cards to buy low-priced commercial goods and services necessary to conduct business.
Sandia employs 9,948 people, 8,856 of them in Albuquerque, according to the report.
The 2011 data is based on Sandia’s fiscal year beginning Oct. 1, 2010, and ending Sept. 30, 2011. The report reflects Sandia’s continued commitment to small business. Labs advocates encourage buyers to do business with small companies.
The Small Business Act mandates that federal contractors use small businesses, including those that are small disadvantaged, owned by women or veterans and service-disabled veterans, and small businesses in impoverished areas — called Historically Underutilized Business (HUB) zones. Sandia’s Small Business Utilization Department oversees the mandate and negotiates small business subcontracting goals with NNSA.
Sandia President and Laboratories Director Paul Hommert has expressed his full understanding and support of the Small Business Act. “Sandia National Laboratories has a long and distinguished record of encouraging and partnering with highly qualified, diverse small business suppliers who assist us in achieving our national security mission,” he says. “We are fully committed to continuing this track record.”
Sandia’s total small business expenditures for fiscal year 2011 and New Mexico breakouts:
|Total small businesses:||$540,428,000||$296,112,000|
|Woman-owned small businesses:||$142,505,000||$115,016,000|
|Businesses in impoverished areas (HUBZone)||$20,998,000||$11,212,000|
|Business owned or co-owned by sociallyand economically disadvantaged person 8(a):||$65,604,000||$55,089,000|
|Veteran-owned small businesses:||$30,130,000||$13,395,000|
|Service-disabled, veteran-owned sm. businesses (SDVOSB)||$11,168,000||$536,000|
Sandia also helps the state’s economy through the New Mexico Small Business Assistance (NMSBA) program established by the state legislature in 2000 to help companies receive technical support from the Labs. In 2010, the Sandia NMSBA provided nearly $2.4 million in technical assistance to 194 New Mexico small businesses in 22 counties. Since 2000, it has provided more than $19.8 million in assistance, according to the report.
The 33 companies in the Sandia Science & Technology Park, a 250-acre master-planned research park adjacent to the Laboratories, employ more than 2,200 people at an average annual wage of $71,612. Investment in the park is more than $351 million.
Sandia employees gave a record-breaking $4.66 million in 2011 to the United Way of Central New Mexico. They logged more than 120,000 volunteer hours in 2010. And they donated more than 1,800 books, a truckload of school supplies, 69,478 pounds of food, 500 holiday gifts, and 518 pairs of new shoes to the community in 2011. -- Nancy Salem
Sandia employees in New Mexico pledged to give a record-breaking $4,663 million to nonprofits through the United Way of Central New Mexico during the annual Employee Caring Program campaign. With contributions from Sandia’s employees in Livermore, Calif., the total raised for charitable causes is nearly $4.92 million.
“Our goal was to exceed last year’s donation of $4.3 million, and we are thrilled our employees and retirees are contributing even more this year,” says Kim Sawyer (0003), Deputy Labs Director and Executive VP for Mission. “Giving back to the community where we live and work has always been a high priority for Sandia, and our employees are committed to making a difference in the lives of those around us.”
“Employees at Sandia National Laboratories have been the backbone of the United Way of Central New Mexico annual fund drive since 1957, providing up to 20 percent of the dollars raised each year,” says Kathleen Avila, chair of the board for United Way of Central New Mexico. “We have relied on Sandia to provide many volunteer leaders in each of those years and they have consistently done so. The corporate and employee citizenship of Sandia National Laboratories cannot be overstated or overvalued. United Way of Central New Mexico applauds Sandia for their exemplary commitment to our community.”
Since 1957, Sandia employees have participated in the annual Employee Caring Program (ECP), which facilitates employee and retiree donations to the community through the local chapter of the United Way. Participants can designate their gift to any 501(c)3 nonprofit agency or to local community funds to help those most vulnerable in the local area. For two weeks last fall, ECP hosted fundraising and awareness events, including book fairs, socials, and health walks. Retirees continue to contribute to the successful campaign, pledging more than $655,988 this year. Lockheed Martin, on behalf of Sandia, contributes $100,000 to the United Way Corporate Cornerstone program, which covers United Way administrative overhead costs so that all donations by employees go directly to the organization of their choice.