Human Amniotic Membrane Allograft: Comparison of Two Preservation Methods in Biocompatibility Assays

Human amniotic membrane is widely used in regenerative medicine (ophthalmology, dermatology, reconstructive surgery, soft tissue augmentation, and dentistry) and tissue engineering. It is an immuno-compatible tissue that has immunomodulatory, antimicrobial and no mutagenic effects, and is also a source of growth factors and cells with stem cell properties that combines adequate mechanical properties with good capacity for cell adhesion to structural components of the extracellular matrix. Several methods are currently used to prepare, store, and sterilize human amniotic membrane allografts that may affect safety and biological properties. The aim of this study was to obtain human amniotic membrane allografts preserved by two methods, cryopreservation and the combination of lyophilization and irradiation, at the Tissue Bank of Laboratorio de Hemoderivados, National University of Córdoba. Subsequently, biocompatibility was evaluated using cytotoxicity, direct irritation and systemic toxicity tests, recommended by ISO 10993:5, 10993:10 and 10993:11, respectively. Results showed that the processing method, as well as the different conservation methods of the amniotic membrane (cryopreserved, and lyophilized and irradiated) were adequate. In the cytotoxicity test, both amniotic membranes showed cell viability greater than 70%, in compliance with ISO 10993:5. In addition, no negative evidence was observed in the primary skin irritation score, nor were there changes in body temperature due to the systemic administration of extracts at the different times tested. Allografts obtained and preserved both by cryopreservation and by the combination of lyophilization and irradiation reveal a good profile making their use in regenerative medicine and tissue engineering very promising.