Hyperdry human amniotic membrane is useful material for tissue engineering: physical, morphological properties, and safety as the new biological material.

Human amniotic membrane (AM) has been used widely as graft biomaterial for a variety of clinical applications. But, there are some persistent problems related to the preparation, storage, and sterilization. To resolve these problems, we developed hyperdry AM (HD-AM) using far-infrared rays, depression of air, and microwaves and then sterilized by γ-ray irradiation. To elucidate the benefit of HD-AM as biological materials, compare with the physical and histological properties of HD-AM with a freeze-dried AM (FD-AM) as typical freeze-dried methods, evaluate the safety of HD-AM in vivo experiment used nude mice, and demonstrate the feasibility of HD-AM transplant in pterygium. The water permeability and the sieving coefficient of HD-AM were significantly lower than that of FD-AM. HD-AM has kept the morphological structure of epithelium and connective tissues. At 18 months after transplanted, single and multilayers of HD-AM in the intraperitoneal cavity was degraded without any infiltrated cells. For clinical treatment, recurrence of pterygium and regrowth of the subconjunctival fibrosis were not observed during the 6-month follow-up periods after the surgery. It was proposed that HD-AM was a safe and effective new biological material for clinical use including treatment for recurrent pterygium.