A newly developed technology that uses a laser and electric fields to manipulate fluids and tiny particles has a range of potential applications, including medical diagnostics. The technology could produce innovative sensors and analytical devices for lab-on-chip applications, or miniature instruments that perform measurements normally requiring large laboratory equipment, according to Steven T. Wereley, Professor of mechanical engineering at Purdue University.
The method, called hybrid optoelectric manipulation in microfluidics, is featured on the cover of the 7 July issue of Lab on a Chip magazine, published by the Royal Society of Chemistry. “This is a cutting-edge technology that has developed over the last decade from research at a handful of universities,” said Aloke Kumar, a Wigner Fellow and staff member at Oak Ridge National Laboratory and lead author of the article, which can be accessed free of charge (registration required).
The technology works by first using a red laser to position a droplet on a platform specially fabricated at Purdue. Next, a highly focused infrared laser is used to heat the droplets, and then electric fields cause the heated liquid to circulate in a microfluidic vortex. This vortex is used to isolate specific types of particles in the circulating liquid, like a microcentrifuge. Particle concentrations replicate the size, location and shape of the infrared laser pattern.
Potential life science applications include lab on chip sensors. “A very important aspect is that we have achieved an integration of technologies that enables manipulation across a very wide length scale spectrum,” Kumar said. “This enables us to manipulate not only big-sized objects like droplets but also tiny DNA molecules inside droplets by using one combined technique. This can greatly enhance efficiency of lab-on-a-chip sensors.”
The technology also may be used as a tool for nanomanufacturing because it shows promise for the assembly of suspended particles, called colloids. The ability to construct objects with colloids makes it possible to create structures with particular mechanical and thermal characteristics to manufacture electronic devices and tiny mechanical parts. The nanomanufacturing applications are at least five years away, said Wereley.