Surface-Enhanced, Spatially Offset Raman Spectroscopy (SESORS) in Tissue Analogues

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Biomedical Optics

Background:

• Surface-enhanced Raman spectroscopy (SERS) offers high sensitivity.
• Spatially offset Raman spectroscopy (SERS) enables non-invasive subsurface analysis.
• Combining SERS and SORS into SESORS promises enhanced in vivo Raman measurements.

Purpose of the Study:

• To demonstrate and advance surface-enhanced, spatially offset Raman spectroscopy (SESORS) for non-invasive, in vivo analysis.
• To evaluate SESORS performance through varying thicknesses of tissue analogues.
• To optimize SESORS for practical utility in a backscattering geometry.

Main Methods:

• Developed SESORS using SERS-active nanoparticles (NPs) spin-coated on glass slides.
• Tested SESORS through six tissue analogues of varying thicknesses.
• Varied spatial offsets of the collection probe in a backscattering optical geometry.

Main Results:

• SESORS demonstrated superior performance compared to SERS alone for subsurface analysis.
• Detection of the NP signal was achieved through tissue thicknesses exceeding 6.75 mm.
• Increased tissue thickness necessitated greater spatial offsets to maximize NP signal detection.

Conclusions:

• SESORS is a promising technique for non-invasive, in vivo Raman measurements.
• The study successfully demonstrated SESORS capabilities through significant tissue depths.
• Optimized spatial offsets and backscattering geometry enhance SESORS utility for biomedical applications.