Zhang, Kai Tian2024-04-292024-04-292024-04-22http://hdl.handle.net/10012/20514Laser tissue welding is an efficient and quick technique used to join tissues for wound repair in the event of injury or surgery. Compared to traditional joining methods such as suturing, optimized laser tissue welding offers a simpler procedure, reduced operator skill requirements, and improved healing. With the use of laser light, exogenous chromophores such as gold nanorods can be added in addition to localize thermal energy and streamline the welding process. The focus of this research is to build upon current understandings of laser tissue welding, using near-infrared irradiation and exogenous chromophores, performed on ex vivo porcine skeletal muscle tissue as a model. To accomplish this goal, laser interactions with porcine skeletal muscle tissue was studied using a parametric approach. By manipulating laser power (0-30 W) and lasing duration (0-20 s), the thermal effects of laser irradiation (Ex. coagulation) on biological tissue was modeled. It produced a threshold whereby laser parameters that cause irreversible tissue damage can be estimated with the model. This information guided welding efforts and may facilitate the safe development of laser-muscle treatments for chronic muscle pain and muscle regeneration through non-thermal effects. Laser welding of porcine skeletal muscle tissue was performed using a continuous wave, near-infrared (1070 nm) fiber laser. A tensile test revealed a 46.7 % recovery in tensile strength. Optical and scanning electron microscopy revealed gaps at the interface which suggests the potential for procedural or parametric changes to improve the weld quality. Exogenous chromophores (gold nanorods) were introduced to the laser tissue welding procedure and was delivered to the tissue in two ways, using a biocompatible hydrogel comprised of hyaluronic acid, and a solid collagen disc. The gold nanorod within these biosolders had an absorbance maximum that was attuned to the continuous wave fiber-coupled diode laser (808 nm) used. A complete seal of an artificial incision on porcine skeletal muscle tissue using the hyaluronic acid hydrogel was achieved within 6 minutes of irradiation time with a power density of 4.7 W/cm2. In addition, welds achieved with the GNR-collagen disc (1.9 W/cm2) with an irradiation time of 4 minutes revealed a 48 % recovery in tensile strength. These results highlight the simplicity of the procedure and strength of the bonds achieved using laser tissue welding. It also showcases the advantages of using gold nanorod-infused biosolders. This study demonstrates their ease of application, versatility with different tissues, and speed. This is evidence that laser tissue welding is a strong alternative to traditional joining techniques and may be useful in optimization of this technique for increased use in surgical scenarios.enlasertissue weldinggold nanoparticlesMaster Thesis