Reusable lab-on-a-chip uses acoustic waves to manipulate fluid droplets

The group, from Duke University in North Carolina, claims that the technology could form the basis of a reusable and programmable biomedical chip for applications ranging from diagnostics to laboratory-based research.

So-called lab-on-a-chip systems have played an increasingly important role in the biomedical and pharmaceutical sectors, but because these devices rely on solid surfaces their application has been hindered by problems related to surface absorption.

"There are a lot of protein-laden fluids and certain reagents that tend to stick to the chips that are handling them," said Tony Jun Huang, the William Bevan Professor of Mechanical Engineering and Materials Science at Duke. "This is especially true of biological samples like undiluted blood, sputum and faecal samples. Our technology is well-suited for processing these difficult samples."

According to a study in the journal Nature Communications the new lab-on-a-chip platform gets around this problem by using a thin layer of inert, immiscible oil to stop droplets from leaving behind any trace of themselves. Just below the oil, a series of piezoelectric transducers vibrate when electricity is passed through them. Just like the surface of a subwoofer, these vibrations create sound waves in the thin layer of oil above them.