Researchers at the University of Central Florida (UCF) in the US are combining nanoscience with the principle of Faraday rotation, a magnetic phenomenon discovered in 1845, in a new method for speedy medical tests.
The team applied the magneto-optical technique, called frequency-domain Faraday rotation spectroscopy—or fd-FRS, to characterize proteins, using antibody-functionalized magnetic nanoparticles (MNPs).
“Fd-FRS is a new way of looking at the interaction between light and magnetized material,” says Shawn Putnam, assistant professor UFC’s College of Engineering & Computer Science. “We covered the surfaces of magnetic nanoparticles with a layer of biological sensors and measured their movement after exposure to their corresponding biological targets for detection.”
Applying a magnetic field and a light source to the sample allowed the scientists to easily read the nanoparticles’ Faraday rotation. The researcher explains that, for example, how “sluggish” the particles become as they attempt to align with the alternating magnetic field provides insight into how many bio-targets have been bound to the particle surface.
Reformulating known science to achieve new goals
“Combining magnetic, optical and nanoparticle science and engineering for biosensor development is not a new approach,” Putnam notes, “but the way we reformulated expertise from these areas into a faster, simpler and competitive characterization technique to join the repertoire of diagnostics available today definitely is.”
Joining improvements such as faster data analysis, low sample volumes and preciser chemistry enabled the team to get medical test results significantly faster and simpler. “Additionally, we have used established molecular adsorption — or binding — models to more fully understand the physics behind this technique’s ability to sense targets,” Putnam says. “Fd-FRS facilitates more efficient diagnosis that medical laboratories can easily incorporate into their daily routines.”
Advantages of Fd-FRS over previous medical testing methods
The expert says currently available methods tend to be time consuming due to the purification and incubation steps necessary before results become available. “Fd-FRS is capable of high-capacity testing due to the small volumes necessary to get a response as well as drastically improved test turnaround times — about 30 minutes compared with about four hours for ELISA,” he says, noting that getting test results quickly is a priority in hospitals, where time is of the essence. “Moreover, our method has been shown to yield a broader detection range and increased sensitivity for a model protein target.”
Bringing Fd-FRS into the real world
The next step for the UCF team is to validate the effect they see with their model protein with clinically relevant proteins, such as those seen as markers for specific diseases and those already used in routine hospital lab workups. “With these results in hand, we would then be in a good position to test and improve our method in the hospital setting, adapting to the needs, workflow, and input of medical personnel,” Putnam says. “The approval process for medical tests presents some important hurdles to overcome, but for a non-invasive and effective method such as this, I would not be surprised to see fd-FRS in clinics around the world in just a few years.”
Next steps in the lab
Putnam and his colleagues are now looking to further improve their pioneering fd-FRS technique by incorporating enhanced plasmonic effects via the use of different baseline materials for the magnetic nanoparticles. Furthermore, they are planning to pursue studies in complex biological environments.
The paper “High-Throughput, Protein-Targeted Biomolecular Detection Using Frequency-Domain Faraday Rotation Spectroscopy” is published in Small.
Written by Sandra Henderson, research editor Novus Light Technologies Today