The development, say the researchers, represents a new class of optical nanotweezers that can trap and detect biomolecules, viruses, and DNA more rapidly. In addition, they say, the technology can also use light to promptly detect cancer or improve the production of medications.
To create the technology, the researchers developed a nanostructured plasmonic metafilm by perforating nanoscale holes in a gold film. By focusing light onto specific spots on the film and by heating up those spots and creating local thermal gradients in the ambient liquid - producing a small tornado-like effect - the metafilm can then act as "tweezers" to capture and trap tiny particles.
Described more technically, the plasmonic metafilms use a combination of thermal and electric fields to create hydrodynamic flows that result in the rapid transport of suspended particles, bringing them to the surface of the metal film for easy trapping and detection.
"All of this," says Alexander Kildishev, an associate professor with Purdue's School of Electrical and Computer Engineering, "is resulting in a revolutionary compact lab-on-a-chip – an innovative approach to detecting and diagnosing a tumor or a viral disease.”
Another advantage of the new system, say the researchers, is the increased ability to sort these tiny particles and then collectively detect sorted patterns such as drug contaminants or water impurities. The technology has potential applications for pharmaceuticals, biohazard detection, and water quality tests.
"To our knowledge, our plasmonic nanotweezers are more robust in trapping and detecting molecules than previous comparable lab-on-a-chip systems," says Kildishev. "Our system also provides better sensitivity and consumes less laser power. We have created an advanced self-contained lab-on-a-chip platform that allows us to trap and detect dangerous particles such as drug and water contaminants and remove them from liquids."
The system is said to be very flexible to control and provides a broad range of functionality. In addition, say the researchers, it uses multifunctional, inexpensive light sources to outperform more