Magnetic “nanobeads” can help detect chemical and biological agents with applications covering bioterrorism, environmental monitoring or even water and food safety.
When fully developed as a hand-held, portable sensor it could provide a whole diagnostic laboratory on a single chip.
The research could revolutionize the size, speed and accuracy of chemical detection systems around the world, said researchers at Oregon State University.
The key to the device is tapping into the capability of ferromagnetic iron oxide nanoparticles –extraordinarily tiny pieces of rust. The use of such particles in the new system can not only detect chemicals with sensitivity and selectivity, but they can also go into a system of integrated circuits to instantly display the findings.
“The particles we’re using are 1,000 times smaller than those now being used in common diagnostic tests, allowing a device to be portable and used in the field,” said Vincent Remcho, an OSU professor of chemistry and also associate dean for research and graduate programs in the College of Science.
“Just as important, however, is that these nanoparticles are made of iron,” he said. “Because of that, we can use magnetism and electronics to make them also function as a signaling device, to give us immediate access to the information available.”
This should result in a powerful sensing technology that is fast, accurate, inexpensive, mass-producible, and small enough to hold in your hand, said Pallavi Dhagat, an assistant professor in the OSU School of Electrical Engineering and Computer Science.
“This could completely change the world of chemical assays,” Dhagat said.
Existing assays are often cumbersome and time consuming, using biochemical probes that require expensive equipment, expert personnel or a complex laboratory to detect or interpret.
In the new approach, tiny nanoparticles could attach to these biochemical probes, tagging along to see what they find. When it detects a chemical of interest, a “ferromagnetic resonance” relays the information electronically to a tiny computer and the information immediately displays. There is no need for special thin films or complex processing, but the detection capability is still extremely sensitive and accurate.
Essentially, the system could detect almost anything of interest in air or water. And the use of what is ordinary, rusty iron should help address issues of safety in the resulting nanotechnology product.
Rapid detection of chemical toxins used in bioterrorism would be possible, including such concerns as anthrax, ricin or smallpox, where there is a need for immediate, accurate and highly sensitive tests.
In addition, the sensor could go toward improving on the effort to monitor commercial water treatment and supplies, along with other needs in environmental monitoring, cargo inspections, biomedical applications in research or medical care, pharmaceutical drug testing, or even more common uses in food safety.