Portable infection: SERS detection
- Published: Jul 1, 2013
- Author: David Bradley
- Channels: Raman
The optical technique of surface-enhanced Raman scattering (SERS) has been used to detect signs of infection in tissue samples before patients even show symptoms of viral disease. The system could be further developed into a portable lab-on-a-chip (LoC) devices for use in the clinic with potential for applications in the developing world.
A group of biomedical engineers and genome researchers - Hsin-Neng Wang, Andrew Fales, Aimee Zaas, Christopher Woods, Thomas Burke, Geoffrey Ginsburg and Tuan Vo-Dinh - at Duke University in Durham, North Carolina, USA, have developed what they refer to as a proof-of-principle approach to using light in order to detect infections before patients show symptoms. They used human samples in their preliminary tests and suggest that their SERS approach could lead to the development of faster and more reliable diagnostic information about a patient. A portable version of the system would preclude the need for samples to be processed and sent to a distant laboratory for time-consuming analysis. The research will ultimately lead to devices that measure multiple genome-derived markers for rapid, but nevertheless accurate, diagnosis of infectious diseases caused by viruses, at the point of care. This would make it very useful for screening people quickly in remote parts of the world and in the aftermath of a natural disaster, on refugee camps, or in war zones, for instance, where infection can quickly become a serious issue for those affected.
The system is based on using a sample solution that contains added silver nanoparticles which are themselves designed so that they can target the specific molecular markers in the blood associated with infection. When the silver nanoparticles are bathed in laser light, this enhances the Raman scattering of from any flagged particles, which provides an optical fingerprint revealing the presence of the substances associated with infection. The team has developed a molecular sentinel nanoprobe to detect the human radical S-adenosyl methionine domain containing 2 (RSAD2) RNA as a model for the approach. The human RSAD2 gene is known to be a host-response biomarker for respiratory infections.
"We have demonstrated for the first time that the use of these nanoprobes can detect specific genetic materials taken from human samples," explains project leader Vo-Dinh. "When the target molecule is coupled with a metal nanoparticle or nanostructure, the Raman response is greatly enhanced often by more than a million times," he adds. The results show that the RSAD2 molecular sentinel nanoprobes are highly specific and can reveal the present of the target sequence at concentrations as low as 1 nanomolar. Vo-Dinh and colleagues reported details this month in the journal Analytica Chimica Acta.
As with much research in the biomedical area an interdisciplinary approach is needed so that chemistry, photonics, spectroscopy, engineering and genetics understanding is drawn together. For over two decades, Vo-Dinh has been working with many collaborators from different fields to develop novel applications for SERS from chemical sensing to medical diagnostics.
"This would guide care decisions that will lead to more effective treatment and improved outcomes of antimicrobial therapy," Geoffrey Ginsburg, director of genomic medicine, explains. "Point-of-care diagnostics holds great promise to accelerate precision medicine and, more importantly, help patients in limited-resource settings gain access to molecular testing."
The researchers were supported by the National Institutes of Health, NIH, the Defense Advanced Research Projects Agency (DARPA), the Department of Defense (DOD) and the Wallace H. Coulter Foundation Endowment.
Anal Chim Acta 2013, 786, 153-158: "Surface-enhanced Raman scattering molecular sentinel nanoprobes for viral infection diagnostics"
Article by David Bradley
The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.