Cutting-edge fabrication processes, new materials, and nanoscale architectures are redefining sensor technology. In the drive to achieve greater miniaturization and new levels of performance, researchers are pushing the envelop of sensing with technologies like 3D printing and materials such as graphene, nanotubes, and photocurable resins. The problem is that, in the rush to introduce and commercialize the next disruptive technology, they don't always wait until they know the full ramifications of the innovations they are introducing.
Consider for example the work done at the UK's National Physical Laboratory. There scientists recently announced that they developed a technique for depositing silver onto clothing fibers. The process bonds a 20 nm layer of silver onto individual fibers, allowing wearable electronics developers to print flexible, lightweight circuits onto complete garments. The technique could be used to incorporate wearable sensors into clothing to monitor health conditions in medical patients, first responders, and athletes.
The prospects of such advances are exciting—that is until you factor in the ongoing discussion among scientists about the potentially dangerous health and environmental effects posed by nanoparticles. Then the benefits are not as clear-cut.
Researchers at Duke University demonstrated that silver nanoparticles used in many commercial products can have an adverse effect on plants and microorganisms after they have entered the ecosystem as by-products of sewage treatment plants. Taking the examination one step further, how great a risk will these materials pose if they are worn close to the body as wearable sensors and electronics?
Unfortunately, the potential risks are not restricted to silver nanoparticles. A study conducted by biologists, engineers, and material scientists at Brown University found that jagged edges of graphene can easily pierce cell membranes and disrupt normal function. "These materials can be inhaled unintentionally, or they may be intentionally injected or implanted as components of new biomedical technologies," said Robert Hurt, professor of engineering and one of the study's authors. The researchers are continuing to look into what happens once graphene gets inside the cell, and this is just one of the first steps in understanding the potential for graphene toxicity.
In another study, this time conducted at the Illinois Institute of Technology, researchers warn that additive manufacturing, which uses a process called molten polymer deposition (MPD), emits ultra-fine particles into the air. The particles, which measure less than 100 nm in diameter, are removed by ventilation systems traditionally found in industrial environments. As 3D printers migrate into smaller manufacturing operations and the commercial arena—environments that may not have adequate ventilation and filtration systems—the particles could cause strokes among workers.
The Jury Is Still Out
None of these studies are definitive. For every article warning of the dangers posed by nanomaterials, you can find a counterview, saying that the risks are minimal. The fact is that the question is complex. Before scientists can assess the effects of nanomaterials on the environment and humans' health, they have to determine to what degree nanoparticles are released from products and how and to what degree do those nanoparticles affect organisms. This will require more evaluation and research.
The best approach would be to learn more about the new processes and materials shaping the next generation of electronics and sensors. As these developments gain momentum, though, it will be difficult for technology providers to wait.
ABOUT THE AUTHOR
Tom Kevan is a New Hampshire-based freelance writer specializing in technology.