Gold nanoshells are a new class of nanoparticles with tunable optical absorption that can be placed in the near infrared. Gold nanoshells consist of a spherical silica core surrounded by a thin gold shell. The ratio of the sizes of the core diameter to the shell thickness as well as the total size of the nanoshell determines the optical absorption properties. Previous experiments have shown that these nanoparticles are stable at >325°C for durations typical of laser tissue welding. We have investigated the use of gold nanoshells as exogenous NIR absorbers to facilitate ex vivo laser tissue soldering. For ex vivo testing, gold nanoshells with peak absorption at approximately 820 nm were suspended in an albumin solder formulation and applied to muscle strips, followed by irradiation of the tissue at 821 nm. Mechanical testing of nanoshell-solder welds in muscle revealed successful fusion of tissues with tensile strengths of the weld site equal to the native tissue. The use of thermally stable nanoshells as an exogenous absorber allows the usage of light sources that are minimally absorbed by tissue components, thereby minimizing damage to surrounding tissue and producing welds sufficient for wound closure.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.