Multiplexed imaging of surface enhanced Raman scattering nanotags in living mice using noninvasive Raman spectroscopy

Area of Science:

• Biomedical Engineering
• Molecular Imaging
• Spectroscopy

Background:

• Raman spectroscopy is an emerging noninvasive preclinical imaging technique.
• It offers high sensitivity and multiplexing capabilities for molecular imaging.

Purpose of the Study:

• To demonstrate Raman spectroscopy's ability to differentiate multiple surface-enhanced Raman scattering (SERS) nanoparticles in vivo.
• To assess the potential for multiplexed imaging in living subjects.

Main Methods:

• Raman spectroscopy was used to analyze up to 10 different SERS nanoparticles injected subcutaneously into a living mouse.
• Five spectrally unique SERS nanoparticles were injected intravenously to image liver accumulation.
• The system's ability to linearly correlate Raman signal with SERS nanoparticle concentration was evaluated.

Main Results:

• Spectral separation of up to 10 SERS nanoparticles was achieved after subcutaneous injection.
• Five intravenously injected SERS nanoparticles were successfully identified and spectrally separated in the liver.
• A strong linear correlation was observed between Raman signal and SERS concentration for both subcutaneous (R(2) = 0.998) and intravenous (R(2) = 0.992) injections.

Conclusions:

• Raman spectroscopy enables noninvasive multiplexed imaging of multiple SERS nanoparticles in living subjects.
• This technique holds significant potential for detecting multiple disease biomarkers simultaneously.
• Optimized Raman imaging systems can provide quantitative analysis of SERS nanoparticle distribution and concentration.