Surface enhanced spatially offset Raman spectroscopic (SESORS) imaging – the next dimension

SESORS - Surface enhanced spatially offset Raman spectroscopy–imaging is explored for the first time in this study. Multiplexed surface enhanced Raman scattering (SERS) signals have been recovered non-invasively from a depth of 20 mm in tissues for the first time and reconstructed to produce a false colour image. Four unique ‘flavours’ of SERS nanoparticles (NPs) were injected into a 20 × 50 × 50 mm porcine tissue block at the corners of a 10 mm square. A transmission Raman data cube was acquired over an 11 × 11 pixel grid made up of 2 mm steps. The signals were reconstructed using the unique peak intensities of each of the nanoparticles. A false colour image of the relative signal levels was produced, demonstrating the capability of multiplexed imaging of SERS nanoparticles using deep Raman spectroscopy. A secondary but no less significant achievement was to demonstrate that Raman signals from SERS nanoparticles can be recovered non-invasively from samples of the order of 45–50 mm thick. This is a significant step forward in the ability to detect and identify vibrational fingerprints within tissue and offers the opportunity to adapt these particles and this approach into a clinical setting for disease diagnosis.