Photodynamic tissue adhesion with chlorin(e6) protein conjugates

PURPOSE. To test the hypothesis that a photodynamic laser-activated tissue solder would perform better in sealing scleral incisions when the photosens itizer was covalently linked to the protein than when it was noncovalently mixed. METHODS. Conjugates and mixtures were prepared between the photosensitizer chlorin(e6) and various proteins (albumin, fibrinogen, and gelatin) in diff erent ratios and used to weld penetrating scleral incisions made in human c adaveric eyes. A blue-green (488-514 nm) argon laser activated the adhesive , and the strength of the closure was measured by increasing the intraocula r pressure until the wound showed leakage. RESULTS. Both covalent conjugates and noncovalent mixtures showed a light c lose-dependent increase in leaking pressure. A preparation of albumin chlor in(e6) conjugate with additional albumin added (2.5 protein to chlorin(e6) molar ratio) showed significantly higher weld strength than other protein c onjugates and mixtures. CONCLUSIONS. This is the first report of dye-protein conjugates as tissue s olders. These conjugates may have applications in ophthalmology.