New holographic method could be used for lab-on-a-chip te...(s able to simultaneously position numero...)

"If you want to pattern individual particles on a massive scale using electrokinetic methods as precisely as we are doing it, it could take hours to days, where we are doing it in seconds," Williams said.

The method offers promise for future "lab-on-a-chip" technology, or using electronic chips to analyze biological samples for medical and environmental applications. Researchers are trying to develop such chips that have a "high throughput," or the ability to quickly detect numerous particles or molecules, such as proteins, using the smallest sample possible.

"For example, a single drop of blood contains millions of red blood cells and countless molecules," Williams said. "You always want to have the smallest sample possible so you don't generate waste and you don't have to use as many chemicals for processing the sample. You want to have a very efficient high throughput type of device."

So-called "optical tweezers" use light to position objects such as cells or molecules.

"You can't use mechanical tweezers to move things like molecules because they are too delicate and will be damaged by conventional tweezers," Kumar said. "That is why techniques like optical tweezing and dielectrophoresis are very popular."

The students also have designed an experiment containing one indium tin oxide plate and one gold plate, an important development because gold is often used in biomedical applications.

"It's a technique that you would likely use in sensors, but we also see definite potential ways in which you could use it to manufacture devices with nanoassembly," Wereley said. "But it's really too soon to talk about scaling this up in a manufacturing setting. We're just beginning to develop this technique."

The researchers recorded videos of the
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