Surface-enhanced spatially offset Raman spectroscopy (SESORS) for biomedical applications
Detection of surface-enhanced Raman scattering (SERS) tagged nanoparticles in-vivo is critical for its potential application in cancer diagnostics, inflammation monitoring, and glucose quantification. However, traditional optical methods are typically limited to surface level detection due to attenuation from layers of highly scattering and absorbing tissue. To break through this depth limitation, we utilize surface-enhanced spatially offset Raman spectroscopy (SESORS), a recent development for probing deep tissue that combines the high SERS signals generated by nanoparticles with a depth resolved detection technique called spatially offset Raman spectroscopy (SORS). We create a series of tissue phantoms that optically mimic tissue and embedded SERS tagged gold nanostars within them to demonstrate the ability of SESORS to distinguish signals from different layers by simply offsetting the excitation spot from the collection spot. We also show the ability to recover the subsurface SERS signal by a scaled subtraction between the spectra obtained at the 0 mm offset position and the spectra obtained at 10 mm offset position, demonstrating the ability of SESORS to isolate the subsurface SERS spectra of tagged nanoparticles.
