Feasibility of diffuse Raman spectroscopy to detect in-vivo molecular changes in the tissue induced by subcutaneous...

Area of Science:

• Biomedical Engineering
• Materials Science
• Spectroscopy

Background:

• Biomaterials elicit host immune responses, known as foreign body responses (FBR).
• Detecting FBR-induced molecular changes in tissue is crucial for biomaterial development.
• Current methods often require animal sacrifice for histological assessment.

Purpose of the Study:

• To investigate the feasibility of using diffuse Raman spectroscopy (DRS) for in-vivo detection of molecular changes in subcutaneous tissue.
• To assess DRS's ability to monitor FBR in response to implanted biomaterials.

Main Methods:

• A mouse model with subcutaneous polyethylene terephthalate (PET) fiber implantation was used.
• Numerical modeling optimized DRS for detecting collagen deposition, a marker of FBR.
• In-situ and in-vivo DRS measurements were performed at various time points post-implantation.

Main Results:

• Post-mortem measurements showed a correlation between the 930 cm⁻¹ Raman band intensity (collagen) and FBR levels.
• In-vivo DRS spectra from live mice also demonstrated this correlation.
• Histology confirmed the FBR-induced collagen deposition.

Conclusions:

• In-vivo DRS is feasible for detecting molecular changes associated with FBR in subcutaneous tissue.
• This technique enables longitudinal FBR monitoring in individual animals, reducing the need for sacrifice.
• DRS shows potential for clinical monitoring of FBR in implant applications.