Healing of rabbits' cornea following laser welding: effect of solid and semisolid formulations containing indocyanine green

Laser-assisted tissue welding using chromophores and/or biomaterials as solders may offer several advantages over conventional methods (sutures and staples) such as reduced inflammation and foreign body response, faster healing, and simplicity. This technique makes it possible to perform sutureless surgery and repair wounds that are difficult or impossible to repair using standard surgical techniques. This in turn may be particularly important in ophthalmology, where conventional sutures may cause inflammation, tissue injury, scarring, and stenosis. The objective of this research was the preparation and technological and biological characterization of new solid (S) and semisolid (SS)formulations containing indocyanine green (ICG), which is a chromophore commonly used in laser welding or tissue soldering. The formulations were aimed at improving the cromophore-assisted laser welding process while ensuring the chemical stability of ICG. Polyvinyl alcohol (PVA), sodium hyaluronate (HYAL), sodium alginate (ALG), 5-methylpyrrolidinone chitosan (MPCh), and tamarind seed polysaccharide (TSP) were chosen as vehicles for the ocular application of ICG. The wetting and hydrophilicity characteristics of the solid formulations (film) were evaluated by contact angle and swelling measurements and correlated with the in vitro release of ICG. The biological efficacy of the formulations was evaluated on a corneal cut in a rabbit model by monitoring the healing process after laser welding and comparing it to the healing process of a conventional suture. The best results were obtained with a solid formulation based on TSP that showed high wettability, good chemical stability, and slow release of ICG. Its use resulted in a rapid and safe healing process.