Lab-on-chip combines laser, electric field

Compiled by BioPhotonics staff

A new technology called hybrid optoelectronic manipulation in microfluidics combines a laser with electric fields and promises a new lab-on-a-chip designed to manipulate DNA, bacteria and viruses for a variety of fundamental science applications.

Purdue University researchers integrated electric fields and laser light to manipulate not only large objects like droplets, but also tiny DNA molecules within those droplets. They said this discovery has enhanced the efficiency of lab-on-a-chip sensors.

A new technology combines a laser and electric fields to manipulate fluids and tiny particles such as bacteria, DNA and viruses for a range of potential applications, including drug manufacturing and food safety. Courtesy of Stuart J. Williams, University of Louisville.

The technology works by first using a red laser to position a droplet on a platform created at Purdue. Then, a highly focused infrared laser heats the droplet, and electric fields cause the heated liquid to circulate in a microfluidic vortex, used to isolate specific types of particles in the circulating liquid. Particle concentrations replicate the size, shape and location of the infrared laser pattern. The process takes less than a second.

The combined technologies are now ready for some applications, including medical diagnostics and environmental samples, said Stuart J. Williams of the University of Louisville. “There are two main thrusts in applications,” he said. “The first is micro- and nanomanufacturing, and the second is lab-on-a-chip sensors. The latter has demonstrated biologically relevant applications in the past couple of years, and its expansion in this field is immediate and ongoing.”

Systems that use the hybrid optoelectronic approach can be designed to precisely manipulate, detect and screen certain types of bacteria, including particular strains that render heavy metals less toxic. The new method also is a potential tool for applications including medical diagnostics, crime scene forensics, pharmaceutical manufacturing, and testing food and water. The scientists also said it may be used someday as a tool for nanomanufacturing because it shows promise of suspended colloids.

The findings appeared online May 20 in Lab on a Chip (doi: 10.1039/C1LC20208A).