A comparison of Cunyite and Fosterite NIR tunable laser tissue welding using native collagen fluorescence imaging

Objective: To evaluate the technique of native collagen fluorescence imagin g for assessing the extent of welded areas for tissues exposed to different near-infrared (NIR) laser wavelengths. Background: Native fluorescence ima ging may be used to identify the distribution of collagen and elastin in ti ssues. Our past work demonstrated that different welding strengths were obt ained under the same laser power conditions using different NIR wavelengths , The role of collagen in tissue welding experiments is not well understood . Methods: Two new NIR tunable lasers were used to weld canine skin. The we lded areas on the surface and in cross sections were analyzed by measuring the spatial distribution of native collagen fluorescence at 380 mm excited by 340 nm radiation, Results: The results show that native collagen fluores cence imaging is a useful technique for analyzing the extent of tissue weld s produced under a range of laser exposures, Fluorescence imaging reveals t he depth of laser interaction with the tissue as well as evaluating collate ral damage to the tissue surface, The welded volume obtained in skin using Cunyite laser exposure at 1,430 nm is deeper than that produced with Forste rite laser exposure at 1,250 nm, The post welded tensile strength for the s ame power density is greater for the Cunyite lasers, Ablated tissue on the surface is more prevalent with Forsterite laser welding at 1,250 nm than wi th Cunyite at 1,430 nm, Conclusion: Native collagen fluorescence can distin guish between tissue welds that have been produced by different NIR wavelen gths, Tissue welding using 1,430 nm radiation is more effective than that u sing 1,250 nm.