Laser tissue welding analyzed using fluorescence, Stokes shift spectroscopy, and Huang-Rhys parameter

Area of Science:

• Biomedical Engineering
• Biophysics
• Materials Science

Background:

• Laser welding offers a precise method for tissue approximation.
• Understanding the molecular impact of laser-tissue interaction is crucial for clinical applications.
• Native water absorption is key for near-infrared laser tissue welding.

Purpose of the Study:

• To investigate the molecular changes in porcine aorta and skin after near-infrared continuous wave laser welding.
• To assess the impact of laser welding on native fluorophores like collagen, elastin, and tryptophan.
• To quantify the changes in the local molecular environment using the Huang-Rhys parameter (S).

Main Methods:

• Utilized 1,450 nm continuous wave near-infrared laser radiation for welding porcine aorta and skin.
• Measured fluorescence spectra of collagen, elastin, and tryptophan in welded and non-welded tissues.
• Determined Huang-Rhys parameter (S) and Stokes shift (Δν(ss)) to evaluate molecular environment changes.

Main Results:

• Fluorescence intensities and Stokes shifts of key native fluorophores were measured.
• Huang-Rhys parameter (S) values were determined for collagen, elastin, and tryptophan.
• S values for both welded and non-welded tissues remained similar and below 3.

Conclusions:

• Near-infrared laser welding minimally alters the intra-tissue molecular environment of porcine aorta and skin.
• The observed minimal changes suggest the laser welding process preserves the native molecular structure.
• Fluorescence spectroscopy is a viable method for assessing molecular integrity post-laser welding.