Biomimetic trilayered silk-based electrospun scaffolds for regeneration of dura mater

Abstract

Dura mater healing is essential to prevent cerebrospinal fluid (CSF) leaks in neurosurgical procedures. Drawing inspiration from the hierarchical structure of native dura mater, we have designed a biomimetic electrospun trilayered scaffold (TLS) utilizing silk fiber to replicate both the structure and function of the original tissue. The electrospun trilayered scaffold comprises three distinct layers: a skull-facing layer constructed from silk fibroin combined with strontium-doped bioactive glass, a gradient inert polyurethane middle layer and a brain-facing layer consisting of polyurethane infused with oregano essential oil. For the first time, oregano essential oil is used in dural substitute to impart potential antibacterial properties. The physicochemical properties of TLS were systematically evaluated using Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), microcomputed tomography (micro-CT) and thermogravimetric analysis. The nanoscale architecture was verified through SEM while micro-CT analysis provided additional insights into the fibrous surfaces of the trilayered scaffold. Surface wettability tests revealed that the wetting characteristics were comparable to those of the native dura mater, with the brain-facing layer exhibiting hydrophobic properties conducive to water-tight dural closure and the skull-facing layer presenting hydrophilic properties favorable for cell adhesion. After immersion in phosphate-buffered saline (PBS) for 28 days, the TLS showed a degradation rate of 13%. Furthermore, the results show that TLS was porous (60%) and demonstrated improved swelling in PBS. The addition of OEO improved the antibacterial potential; the TLS exhibited 80% antibacterial activity against Escherichia coli after 48 hours. Furthermore, the fibroblast cell line was exploited to assess the biological properties of TLS. Cell culture results indicated that TLS promoted NIH3T3 proliferation in the 3D microenvironments and was non-toxic. Similarly, live/dead and migration assay results further confirmed the biocompatibility of TLS with increased cell viability and 99% wound closure after 24 hours. Overall, we were able to manufacture a trilayered scaffold that architecturally mimics the native structure of dura mater.