New Method Uses Light and Electric Fields to Stabilise Small Biological Samples

This image shows a new "hybrid optoelectric" device that uses a combination of light and electric fields to position droplets and tiny particles, such as bacteria, viruses and DNA, representing a potential new tool for medical diagnostics. Image courtesy of Craig Snoeyink/Purdue University Birck Nanotechnology Center.

Researchers at Purdue University have developed a potential new tool for medical diagnostics. The technique uses a combination of light and electric fields to position droplets and tiny particles, such as bacteria, viruses and DNA, which are contained inside the drops.

Other methods using either light or electric fields separately are able to position droplets or the particles they contain, but the new “hybrid optoelectric” device can do both, making it potentially practical for sensors and industrial processes, says mechanical engineering doctoral student Aloke Kumar.

Ordinarily, the particles inside droplets are detected when they randomly fall on a sensor’s surface. However, the new method could improve sensor efficiency by actively moving particles to specific regions on an electronic chip for detection or analysis.

“This new hybrid technique is universal in the sense that we can manipulate a range of droplet and particle sizes, going all the way from microlitre drops to particles a few nanometers long,” says Steven T. Wereley, a professor of mechanical engineering who is working with Kumar.

The method offers promise for future “lab-on-a-chip” technology, using electronic chips to analyse biological samples for medical and environmental applications. Sensors based on the technique could make possible a new class of chemical analyses, or assays, with point-of-care devices in a doctor’s office or hospitals.

Such sensors might be used to quickly analyse blood, urine and other bodily fluids for a range of applications, including drug screening; detecting coronary artery disease, tumors and various inherited diseases including cystic fibrosis; and detecting infectious diseases and bacteria, viruses and fungi that are difficult to culture using conventional laboratory methods.

This diagram depicts the design of a new "hybrid optoelectric" device, which uses a tightly focused infrared laser beam to position tiny particles, such as viruses and bacteria, onto a sensor. Image courtesy of Han-Sheng Chuang/Purdue University Birck Nanotechnology Center.

More information on the research is available from Purdue University.

Tags: bacteria, DNA, Purdue University, Sensors, viruses