Fluorescence spectroscopic imaging to detect changes in collagen and elastin following laser tissue welding

Objective: A study was performed to evaluate the use of native fluorescence imaging to detect in situ molecular changes. Summary background data: There is no ideal noninvasive method to monitor molecular changes in a local region at a laser weld joint without removing a section of tissue for histological examination. Methods: Two sections of animal skin were welded together border to border using a Ti:sapphire laser beam (800 nm), Fluorescence imaging was performed on the cross section of the welded site at specific emission wavelengths (lambda(c)) for collagen at 380 nm and for elastin at 450 nm using excitation wavelengths (lambda(e)) of 340 mn, and 380 mn, respectively. Results: A reduction of the collagen and elastin emission was observed in the fluorescence images of the welded region. These results were confirmed with histology using picrosirius red F3BA under polarized light and orcein stains. Conclusion: Optical spectroscopic imaging offers a new noninvasive detecting method for microscopic evaluation of laser tissue welding.