Research Project
7928456
DESCRIPTION (provided by applicant): The significance of this project is the development of a laser assisted tissue welding technique to close corneal wounds, provide a foundation for innovative treatment of eye disease and demonstrate the unique properties of a laser cured collagen adhesive to repair ophthalmic tissue with superior strength and stability. Millions of ophthalmic procedures are performed annually, most incorporating sutures to close and seal wounds. Yet this method can cause severe complications, can weaken the integrity of the eye and may pose a risk for ocular rupture in the case of blunt trauma. Other techniques to close wounds, including the use of tissue glues or grafting, can be even more problematic. Phase I studies were conducted to measure the biostability of solder formulations, evaluate tissue bonding strategies and compare wound stability as a function of intrachamber pressure in four in vitro models of clinical corneal surgery: radial keratotomy, LASIK flaps, penetrating keratoplasty and cataract excision. The results confirmed that the laser solder approach is superior to standard sutures with no evidence of tissue shrinkage. The strength of the soldered repair was dependent upon reaching a precise temperature set by choice of laser, solder composition and film thickness. Solder biostability is increased by reaction with a standard cross linking reagent. The specific aim for Phase II is to optimize solder processing, laser techniques and surgical outcome in survivor animal surgical models. Task descriptions include preparation of sterile solder under stringent process controls, design and assembly of a compact preclinical laser systems, optimization of a laser hand piece and perform ex vivo and in vivo experiments on a lapine model. Surgical endpoints will include the quality of the wound seal, the extent, if any, of collateral thermal tissue damage, solder stability and biocompatibility. The current methods for closing ocular incisions, similar to other body tissue, require placing sutures to bring tissue edges in apposition. The presence of sutures in the cornea leads to patient discomfort, visual distortions, risk for bacterial proliferation and keratitis. The use of a biological tissue adhesive, with sufficient sealing properties to resist sudden changes in intraocular pressure for a prolonged time, may be of great benefit for the synthesis of corneal wounds, caused either by trauma or induced by surgery.
