Polymer-capped fiber-optic Raman probe for non-invasive Raman spectroscopy

Area of Science:

• Biomedical Optics
• Spectroscopy
• Materials Science

Background:

• Raman spectroscopy is advancing for clinical applications.
• Minimizing background noise and generating reference signals for tissue albedo correction are critical challenges.
• Accurate quantification of tissue composition requires addressing variations in tissue optical properties.

Purpose of the Study:

• To develop a fiber optic probe for quantitative, non-invasive Raman spectroscopy.
• To address the need for reliable reference Raman signals to correct for tissue albedo variations.
• To demonstrate the probe's utility in analyzing various tissue types.

Main Methods:

• Development of a fiber optic probe with a fluorinated ethylene-propylene copolymer (FEP) cap.
• Utilizing the FEP cap to generate a 732 cm(-1) reference Raman band via laser transmission.
• Testing the probe with rat leg phantoms and ex-vivo rat tibia for quantitative spectroscopy.
• Measuring the linear relationship between laser power and reference signal intensity.

Main Results:

• The FEP cap generates a usable reference Raman signal with minimal insertion loss (~5%).
• The intensity of the reference Raman band scales linearly with delivered laser power.
• Successful application of the probe for quantitative non-invasive Raman spectroscopy of animal tissues.
• Ex-vivo spectroscopy of rat tibia confirmed the probe's applicability to diverse tissues.

Conclusions:

• The developed fiber optic probe effectively generates a reference Raman signal for quantitative spectroscopy.
• This innovation addresses a key limitation in clinical Raman spectroscopy by correcting for tissue albedo.
• The probe shows promise for multiple spectroscopic applications in biological and clinical settings.