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: Ther e is no ideal noninvasive method to monitor molecular changes in a local re gion at a laser weld joint without removing a section of tissue for histolo gical examination. Methods: Two sections of animal skin were welded togethe r border to border using a Ti:sapphire laser beam (800 nm), Fluorescence im aging was performed on the cross section of the welded site at specific emi ssion 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, respect ively. Results: A reduction of the collagen and elastin emission was observ ed in the fluorescence images of the welded region. These results were conf irmed with histology using picrosirius red F3BA under polarized light and o rcein stains. Conclusion: Optical spectroscopic imaging offers a new noninv asive detecting method for microscopic evaluation of laser tissue welding.