Photocrosslinkable human amniotic membrane hydrogel for recovery from spinal cord injury

The recovery and reconstruction of central nervous system function after spinal cord injury (SCI) is a worldwide problem. The difficulty lies in the feasibility issue of new axons passing through the injured area and the negative effect of scarring after injury. As a biological material, the human amniotic membrane (HAM) has the advantages of protecting nerve growth, inhibiting scar formation, and promoting neovascularization, but its weak physical properties are difficult to apply in treating SCI. In this study, HAMs were first decellularized and then chemically grafted with methacrylic anhydride. Next, the composite was photocrosslinked with gelatin methacrylate to prepare a cross-network biological complex. The final complexes prepared by appeal were used for in vitro and in vivo studies of SCI in rats, separately. In the in vitro experiment, the composite scaffold inherited abundant biological factors from the amniotic membrane and had the physical properties of a hydrogel, thus providing a favorable environment for the growth and development of neurons and blood vessels. In the in vivo experiment, the composite reduced scarring and promoted the growth of new nerves. Overall, the composite scaffolds can stably simulate the extracellular microenvironment in SCI defects, regulate pathological changes, and promote the generation of new neurons. Therefore, decellularized HAM hydrogels are promising biocomposite materials for central nerve repair after SCI. Graphic abstract