SPECTROSCOPY/NANOTECHNOLOGY: SERS approach detects infection before symptoms appear

Sept. 25, 2013
A new proof-of-concept approach uses light to detect infections before patients show symptoms.

A new proof-of-concept approach uses light to detect infections before patients show symptoms.1 Biomedical engineers and genome researchers at Duke University (Durham, NC) have teamed up to develop a nanoparticle able to find a molecular marker that appears in the bloodstream at very early stages of an infection. When light is aimed at a sample of infected blood, the nanoparticle—attached to the marker—reflects back.

The researchers demonstrated the approach in human samples; they are now developing the technique for placement on a chip, which they say could provide fast, simple, and reliable information. A diagnostic device based on this chip also could be made portable.

The operation of the approach is a demonstration of surface-enhanced Raman scattering (SERS): When light is shined on a sample, the target molecule vibrates and scatters back its distinct optical fingerprint, called the Raman scatter. While the Raman response is extremely weak, coupling the molecule with a metal nanoparticle enhances it—often by more than a million times, according to Tuan Vo-Dinh, a distinguished professor of biomedical engineering at Duke's Pratt School of Engineering and director of the Fitzpatrick Institute for Photonics.

The study paves the way for development of devices that measure multiple genome-derived markers, which will enable faster and more accurate diagnosis of infectious disease at the point of care, said Geoffrey Ginsburg, director of genomic medicine at Duke's Institute for Genome Sciences & Policy (IGSP). IGSP scientists separately developed a method of measuring host response to infection through RNA profiling.

Ginsburg noted that care decisions based on the resulting information will lead to more effective treatment and improved outcomes, and added, "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."

1. H.N. Wang et al., Analytica Chimica Acta, 786, 153–158 (2013).

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