SERS Nanoprobe

Optical Fiber SERS Probes

The SERS (Surface Enhanced Raman Spectroscopy) nanoprobe is a component being developed to enable the microscopic tip of an optical fiber to be used in biosensors.

It is being developed for nanotechnology applications from military and water monitoring applications to medical environments.

SERS Nanoprobes - View Information Sheet

Background

Raman spectroscopy utilises an intense laser light source to probe the chemical composition of a sample.  A small portion of the light is shifted in a characteristic manner and provides a spectrum, which can then be compared against spectral libraries to provide a chemical identification.  There is no sample preparation required, and the Raman signal is unaffected by glass containers or water content.  With modern instrumentation, Raman spectra can be collected and analysed in a matter of minutes.  More widespread use of this technology is limited by the modest sensitivity of the technique and by the high cost (>$150,000) of research grade instruments.

Surface-enhanced Raman scattering (SERS) exploits an effect whereby chemicals in close proximity to a roughened metal surface (usually gold or silver) have a greatly increased Raman response (typically by a factor of 106).  SERS is currently attracting attention as a candidate technique for in-vivo glucose sensing, cancer diagnostics and detection of trace contaminants in water.  As a result, considerable research is being undertaken in the development of suitable metal surfaces for SERS.  A research group at Swinburne University of Technology, led by Dr Paul Stoddart, has developed a robust and accurate fabrication technique for producing high-quality SERS substrates on the tips of optical fibers.  Optical fibers have been widely used in normal Raman scattering to increase the ease of sampling in remote and hazardous environments.  However, until recently, the challenge of fabricating stable, reproducible nanometre scale roughness on a fiber tip had not been satisfactorily met.