Solubility study of albumin solders for laser tissue-welding

Background/Objective: Current albumin solders for tissue-welding are soluble in physiological fluids, prior to laser irradiation. These solders are therefore subjected to mechanical alterations, which can weaken the solder-tissue repair. In this study, an albumin solder (laser activated) was developed with low solubility and with the ability to retain (partially) its mechanical characteristics in saline solution. Study Design/Materials and Methods: Gauged protein samples of solder were immersed into 0.5 ml saline solution for fixed intervals of time. The solder samples contained four Bovine Serum Albumin (BSA) concentrations: 56%, 66%, 70%, and 75% (by weight). A Bradford protein assay measured the BSA solubility of the solders. The 70% and 75% BSA solders were also used to weld in vitro Wistar rat intestine sections with a diode laser (λ = 810 nm, power = 270 mW). Results: The solubility of the 75% BSA solder was significantly decreased with respect to the other solders (Anova, P < 0.05). This solder also showed comparable weld strength (13 gm) to the 70% BSA solder. Conclusion: The 75% BSA solder strongly reduced the albumin solubility in saline solution, without affecting its tissue-welding properties.