Novel solid protein solder designs for laser-assisted tissue repair

Background and Objectives: Previous studies have shown that the application of chromophore-enhanced albumin protein solders to augment laser tissue re pairs significantly improves repair strength, enhances edge co-optation, an d reduces thermal tissue injury. These investigations are furthered with th is in vitro study conducted to assess a new range of specially designed chr omophore-enhanced solid protein solders manufactured and tested for applica tion during laser-assisted tissue repair. Study Design/Materials and Methods: The experimental study was divided into three parts. In the first part of the study, the creation of a chromophore concentration gradient across the thickness of the solid protein solder wa s investigated as a means to improve control of the heat source gradient th rough the solder during laser irradiation. In the second part of the study, predenaturation of the solid protein solder was investigated as a means fo r enhancing the stability of the solder in physiological fluids before irra diation. Finally, in the third part of the study, the feasibility of using synthetic polymers as a scaffold for traditional albumin protein solder mix es was investigated as a means of improving the flexibility of the solder. Results: Uniform denaturation across the thickness of the solder was achiev ed by controlling the chromophore concentration gradient, thus ensuring sta ble solder-tissue fusion when the specimen was submerged in a hydrated envi ronment. Predenaturation of the solid protein solder significantly reduced the solubility of the solder, and consequently, improved the handling chara cteristics of the solder. The solder-doped polymer membranes were flexible enough to be wrapped around tissue, whereas their solid nature avoided prob lems associated with "runaway" of the less viscous liquid solders currently used by researchers. In addition, the solder-doped polymer membranes could be easily tailored to a wide range of geometries suitable to many clinical applications. Conclusion: The novel solid protein solder designs presented here add a new dimension to tissue repair as their flexible, moldable, and absorption con trollable nature, greatly improves the clinical applicability of laser-assi sted tissue repair. Lasers Surg. Med. 27:147-157, 2000. (C) 2000 Wiley-Liss , Inc.