Making better biosensors with electron density waves

Oct 22, 2010

An emerging field with the tongue-twisting name of "optofluidic plasmonics" promises a new way to detect and analyze biological molecules for drug discovery, medical diagnostics, and the detection of biochemical weapons. Investigators at the University of California, San Diego led by Yeshaiahu Fainman have succeeded in merging a microfluidics system with plasmonics -- sometimes called "light on a wire" -- onto a single platform. Plasmonics is based on electron waves on a metal surface excited by incoming light waves.

According to Fainman, tapping the potential of plasmonics for biomolecule detection systems has been a challenge, because localized optical field scales are usually much larger than the molecules in question. In order to make a useful optical biosensor, he says, "We need to increase the interaction cross-section by finding ways to localize optical interrogation fields ideally to the scales comparable to those of biomolecules." Since that is not currently possible, he and his team used an approach of integrating microfluidics and plasmonics on single chips, allowing fluid to ferry the molecules into the cross-section of the optical field.

Fainman expects the system to be particularly useful in studying large arrays of protein-protein interactions for identifying potential drugs that bind to specific target molecules, which may lead to earlier cancer diagnoses and faster discovery of new drugs. Unlike most current methods, does not require labeling of molecules with fluorescent or radioactive entities -- labels often hinder interaction by covering up or blocking binding surfaces.

The new platform also carries the advantage of being high throughput and multiplexed, offering researchers an opportunity to examine thousands of arrayed compounds simultaneously, which, he says, "biologists and physicians get very excited about."

Fainman will present these results at Frontiers in Optics (FiO) 2010/Laser Science XXVI -- the 94th annual meeting of the Optical Society (OSA).

Explore further: New imaging technique shows how cocaine shuts down blood flow in mouse brains

More information: The presentation, "Optofluidic Nano-Plasmonics for Biochemical Sensing" is at 4 p.m. on Tuesday, Oct. 26.

add to favorites email to friend print save as pdf

Related Stories

Molecular machines drive plasmonic nanoswitches

Feb 11, 2009

Plasmonics -- a possible replacement for current computing approaches -- may pave the way for the next generation of computers that operate faster and store more information than electronically-based systems and are smaller ...

Direct laser cooling of molecules

Oct 21, 2010

Cooling molecules with lasers is harder than cooling individual atoms with lasers. The very process of laser cooling, in which atoms are buffeted by thousands of photons, was thought by many to be impossible for molecules ...

Recommended for you

Single laser stops molecular tumbling motion instantly

1 hour ago

In the quantum world, making the simple atom behave is one thing, but making the more complex molecule behave is another story. Now Northwestern University scientists have figured out an elegant way to stop a molecule from ...

Ray tracing and beyond

22 hours ago

Ray tracing is simple to explain at one level: "We all do it all day long: That's how you navigate the world visually," Gene Tracy explains. "The fact that I know that you're sitting there and not over there is because the ...

User comments : 0