Spatiotemporal Modeling of Laser Tissue Welding of Plasmonic Nanoparticles

Occurrences of surgical site infection can be decreased by suture-free techniques that create a rapid hydroseal. Plasmonic nanocomposites composed of a collagen protein matrix embedded with gold nanorods convert near-infrared radiation to fuse apposing tissue in colorectal anastamoses as a suture-free technique known as laser tissue welding. In brief, the exogenous chromophore gold nanorods convert the near-infrared light to heat sufficient to denature and then interdigitate native tissue proteins. The results of a spatiotemporal model of heat transfer in laser tissue welding is presented, supplemented by ex vivo experimental results. As high as 68% of native tissue ultimate tensile strength and 48% of burst pressure are retained through laser tissue welding at clinically relevant times and at the lowest laser power densities yet recorded (2.5 W/cm² and lower). These experimental results are accompanied by a spatiotemporal model of the heat generated by the nanocomposites during laser exposure and how that heat is transferred to the peripheral tissue. The model results suggest that this laser welding technique using collagen-gold nanorod composites can be tuned to minimize thermal damage to peripheral tissue and apposing tissue while still providing a rapidly formed, fluid-tight seal to friable tissue.