Accumulative small droplet laser soldering

We conducted in vitro laser fusion experiments of bovine aorta using successive accumulation of solder droplets. The solder was composed of serum albumin, sodium hyaluronate and Indocyanine Green dye. After depositing 0.2 μL of the solder onto an aorta incision with a micro-pipette, we used a diode laser at 808 nm with fixed energy parameters to coagulate the solder droplet. A solder strip was formed from 10 droplets photocoagulated to increase the solder-tissue contact area and coagulum volume. Repair of aorta incision was achieved with both a single solder strip and double solder strips. For half of the welded specimens, tensile measurement was performed immediately following solder experiments. Tensile strength was measured in the rest of the specimens after soaking in saline for 24 hours. Scanning electron microscopy was performed on selected specimens. The average ultimate tensile strengths for the single strip group were 261 N/cm² for acute, and 81 N/cm² after 1 day of saline immersion. The average ultimate tensile strengths for the double strip group were 253 N/cm² for acute, and 77 N/cm² after soaking in saline for 1 day. We also measured native aorta ultimate tensile strength, which was 76 N/cm². This study demonstrated the feasibility of using micro droplets of solder to increase tensile strength.