Human Amniotic Membrane: A Versatile Scaffold for Tissue Engineering

The human amniotic membrane (hAM) is a collagen-based extracellular matrix derived from the human placenta. It is a readily available, inexpensive, and naturally biocompatible material. Over the past decade, the development of tissue engineering and regenerative medicine, along with new decellularization protocols, has recast this simple biomaterial as a tunable matrix for cellularized tissue engineered constructs. Thanks to its biocompatibility, decellularized hAM is now commonly used in a broad range of medical fields. New preparation techniques and composite scaffold strategies have also emerged as ways to tune the properties of this scaffold. The current state of understanding about the hAM as a biomaterial is summarized in this review. We examine the processing techniques available for the hAM, addressing their effect on the mechanical properties, biodegradation, and cellular response of processed scaffolds. The latest in vitro applications, in vivo studies, clinical trials, and commercially available products based on the hAM are reported, organized by medical field. We also look at the possible alterations to the hAM to tune its properties, either through composite materials incorporating decellularized hAM, chemical cross-linking, or innovative layering and tissue preparation strategies. Overall, this review compiles the current literature about the myriad capabilities of the human amniotic membrane, providing a much-needed update on this biomaterial.