Comparative evaluation of the mechanical properties of amniotic membranes for corneal grafting: Effects of cryopreservation, lyophilization, and dehydration.

Abstract

In both human and veterinary ophthalmology, stromal to full-thickness corneal defects can be treated using several techniques that involve various biomaterials, which support healing while preserving vision. Among these, the amniotic membrane stands out due to its multifaceted biological properties, including anti-inflammatory, antimicrobial, and regenerative capabilities. Three main preservation methods (cryopreservation, dehydration, and lyophilization) have been developed to facilitate amniotic membrane clinical use. However, these methods may significantly alter its mechanical and structural integrity, which are critical for graft success. This study investigates the mechanical performance of bovine amniotic membranes for veterinary use, preserved using the above-mentioned techniques, by means of uniaxial tensile and inflation tests in a non-biological in vitro setting. Structural and chemical differences are also analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Despite structural differences arose among the samples, these differences did not alter or worsen the structural resistance of the membranes. All samples withstood 5 inflation cycles of 200 mmHg without leaking.