Silk fibroin sponge combined with cell-derived ECM for tissue-engineered 3D functional neural tissues

Abstract

The construction of engineered neural tissue using cell-derived extracellular matrix (ECM)-modified scaffolds is a promising approach. Silk fibroin (SF) sponge is an advantageous scaffold for the construction of engineered neural tissues, but it can still be modified to enhance its bioactivity. Inactivated mouse embryonic fibroblasts (MEFs) are proven that they can secrete amounts of ECM and soluble factors including neurotrophic factors. MEFs-derived ECM is expected to improve the activity of the scaffold. Here we aimed to construct 3D functional neural tissues based on MEFs-derived ECM modified SF sponge. MEFs were cultured on porous SF sponges and decellularized with TritonX-100 and NH4OH. The decellularized ECM deposited scaffolds were characterized through scanning electron microscopy and confocal microscopy. The efficiency of decellularization was evaluated by quantifying remaining DNA. Besides, we investigated the primary cortical neuronal growth and 3D neural network formation effect on MEFs-derived ECM modified SF sponges. Compared to bare SF sponges, ECM-SF sponges showed improved neuronal growth and axon extension indicated by immunofluorescence staining and RT-PCR. Specifically, ECM-SF sponges showed increased 3D neural network formation with functional connectivity. Hence, this study demonstrated that functionalization of SF scaffolds using cell-derived ECM could improve the bioactivity of SF materials and provide an ideal microenvironment for functional neural tissue formation.