(192a) Laser Tissue Welding Using Polypeptide-Gold Nanorod Solders

Laser-assisted tissue welding is a “sutureless” surgical method for the anastomosis of ruptured tissues. In surgical wound closure, there are several potential advantages using laser-assisted tissue welding over conventional suturing and stapling procedures. Advantages include fast scar-free surgical operation, less complications and accelerated healing. Laser welding results in an immediate fluid-tight sealing, and therefore, enhanced mechanical integrity of the weld site, all of which can be achieved in a reduced operative time.

One of the major concerns associated with laser-assisted tissue welding is the insufficient anastomoses strength. The problem can be addressed by the introduction of protein-based solders (e.g. chitosan-, collagen- and albumin-based) in concert with light absorbing chromophores (e.g. indocyanine green (ICG), fluorescein, iron oxide and gold nanoparticles). Presence of protein-based solders can (a) minimize peripheral tissue destruction, (b) improve the tensile strength of the closure and (c) reduce foreign body responses. Whereas, chromophores pretreated to tissue of interest or incorporated into solders can (i) efficiently transfer lower dose light energy into sufficient localized heat energy for laser welding, and (ii) reduce the thermal damage to peripheral tissue.

We have first time reported the formation/characterization of elastin-like polypeptide hybrid gold nanorod (ELP-GNR) nanocomposite, which advances current solders in several aspects: (1) Gold nanorods better organic dyes in terms of chromophore stability, photochemical stability and minimum diffusivity. Most importantly, the laser dosage required to induce similar thermal response using gold nanostructures is 10- to 25- fold lower than with light absorbing dyes; this may further reduce thermal damage of the periphery tissue. (2) Artificial elastin like polypeptides has been repeatedly reported to be biocompatible and low immunogenicity.

In this study we describe the use of ELP-GNR nanocomposites as novel adhesives for laser-assisted tissue welding using porcine intestine model, holding the potential advantages to replace/improve conventional suturing and stapling in wound closure. In addition, these nanocomposites were demonstrated as cell supporting platforms for potentially aiding / enhancing the wound healing process, their mechanical properties were also investigated.