Seeing through bone with surface-enhanced spatially offset Raman spectroscopy

Area of Science:

• Biophotonics
• Spectroscopy
• Biomedical Imaging

Background:

• Surface-enhanced spatially offset Raman spectroscopy (SESORS) is a label-free technique with potential for in vivo imaging.
• Previous SESORS applications were limited to subcutaneous or embedded SERS substrates.
• In vivo imaging through bone has remained a significant challenge.

Purpose of the Study:

• To demonstrate SESORS measurements through bone.
• To assess the detection limits of SESORS through bone.
• To explore quantitative analysis of through-bone SESORS data.

Main Methods:

• Utilized SERS-active nanoparticles (nanotags) coated with Raman reporter molecules.
• Acquired SESORS spectra through bone samples of varying thicknesses (3-8 mm).
• Employed least-squares support vector machine analysis for quantitative detection.

Main Results:

• Successfully acquired SESORS spectra through 3-8 mm of bone.
• Demonstrated detection of diluted nanotag samples (~2 × 10(12) particles) through bone.
• Validated quantitative detection capabilities using machine learning analysis.

Conclusions:

• SESORS can effectively measure through bone, overcoming previous limitations.
• This technique shows promise for non-invasive, real-time spectroscopic monitoring of neurochemicals through the skull.
• Through-bone SESORS opens new avenues for biomedical applications requiring deep tissue imaging.