Plasmonic Nanocomposites for Laser Tissue Welding with Spatiotemporal Modeling

Surgical site infection is very common in gastrointestinal surgeries, and suture-free techniques that create a rapid hydroseal can combat these infections. Plasmonic nanocomposites composed of a collagen protein matrix embedded with gold nanorods tuned to absorb near-infrared radiation are used 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 interdigitate native tissue proteins. The results of ex vivo treatments as well as a spatiotemporal model of laser tissue welding are presented. 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 while still providing a rapidly formed, fluid-tight seal to friable tissue.