Lyopreservation and Nonionic Decellularization of Human Amnion Scaffolds for Enhancing Regeneration in Chronic Nonhealing Ulcers

Chronic nonhealing ulcers are responsible for considerable morbidity, given the increasing prevalence of type II diabetes and other comorbid conditions that further worsen healing. This study introduced shelf-stable decellularized and lyopreserved human amnion grafts for treating difficult-to-heal wounds. The processing approach (comprising a unique combination of nonionic surfactants and trehalose lyopreservation) applied to develop these bioscaffolds maximized the retention of sulfated glycosaminoglycans while enhancing both tensile property and hydrophilicity. Postprocessing, the tensile properties were found to be similar to human skin (5.33 ± 2.45 MPa). Additionally, the surface hydrophilicity of the lyopreserved grafts was increased. It also exhibited optimum moisture transmissibility (evaluated as per BS EN 13726-2 standards), similar to moist wound dressing (1625 ± 375 g/m²/day). Biochemical attributes including total acid-soluble proteins (481.140 ± 14.95 μg/mL) and collagen (9.01 ± 0.15 mg/mL) were well retained as compared to the fresh membrane. Notably, the sulfated glycosaminoglycan content of the processed grafts was well conserved (there was only a 21.14% reduction, which was substantially lower than the reduction achieved by conventionally used surfactants for processing biological tissues). The regenerative efficacy of these bioactive scaffolds was evaluated through preclinical testing in a diabetic rodent wound model. It showed a 50% reduction in time to heal compared to the standard of care dressings, supported by increased vascular endothelial growth factor (VEGF) expression in the healed tissues. This can be collectively attributed to the conservation of sulfated glycosaminoglycans (GAGs) and the enhanced scaffold tensile quality, which play key roles in promoting angiogenesis, and tissue regeneration in diabetic wound beds. As a result, these grafts are well suited for a variety of soft tissue reconstruction applications and can also serve as bioactive scaffolds for culturing autologous cells, making them versatile tools in regenerative medicine.