Experimental research on mechanism of collagen remodeling and excellent properties of skin incisions under dual beam laser welding

Abstract

For problems of water loss caused by rapid energy dissipation and insufficient depth of heat-affected zone (HAZ) during skin welding with single laser beam. A dual beam 1064 nm semiconductor laser was used to weld incisions on the back of porcine skin, and the dual beam laser was consisted of preliminary beam and the secondary beam. The main beam is vertically incident, and the secondary beam is deflected by 30° on a vertical basis. In this study, there are three types of energy ratios of dual beam laser, which are 1:1, 2:1 and 3:1. From 77.22 J/cm2 to 135.4 J/cm2 stepped increasing energy density, the fusion performances of skin incisions after welding were comprehensively analyzed and characterized. Using Matlab and high-precision dynamometer to evaluate thermal denaturation and biomechanical properties, combined with H&E staining, Masson and Sirius red staining to analyze the microstructure characteristics, collagen deposition behavior and distribution around the HAZ of incisions after welding. The results showed that when the energy density was 102.96 J/cm2, at the energy ratio of 1:1, the collagen network structure was dense, collagen deposition was 48 %, thermal damage value was 0.39, and the immediate tensile strength was 206.3 N/cm2, which was far above the standard of wound healing performances after surgical treatment, and the thermal denaturation was controlled at a low level, realizing the reconstruction of collagen after fracture, achieving the optimal dual-beam laser welding performance, in vivo test results found that above laser type and energy ratio can reduce healing cycle into 7 days, which provided important references for later study on laser tissue welding technology.