Neural Stem Cells Biocompatibility on Silicon and Silicon Carbide surface: a new approach on neurodegenerative disease

In the last few years, Silicon wafers have attracted considerable scientific interest as a promising biomaterial for medical applications for the manufacture of implantable medical devices as in the context of neurodegenerative diseases. Since the use of silicon involves responsibilities due to its toxicity, the investigation is moving towards a new class of composite semiconductors, including the Silicon Carbide (3C-SiC). The main concerns in the material research for biomedical applications is to find a suitable material that produces low or no adverse effect when grafted in the body, that can be implanted for long term and are capable of interfacing with electronic devices. In the field of semiconductors, Silicon (Si) has always been the preferred substrate material for micro-devices due to its low cost and ready availability (1). The aim of our work has been to test the biocompatibility levels of Si and 3C-SiC in an in vitro model of human neurons derived from dental pulp mesenchymal stem cells (DP-NSCs) (2,3) and murine Olfactory Ensheathing Cells (OECs), a particular glial cell type derived from olfactory bulbs, which shows stem cell characteristics (4). To assess the biocompatibility of these substrates, we investigated the mitochondrial membrane potential, cytotoxicity and morphological changes. Moreover, we assessed by immunocytochemical assay the expression of markers, such as Nestin, as stem cell marker, GFAP, as astroglial cell marker, S-100, as specific OEC marker and MAP2 and Neurofilament, as neuronal cytoscheletric markers. We found that the 3C-SiC avoided the oxidative stress and it was not visible adverse reaction on mitochondrial membrane potential and morphological modification. In addition, our results demonstrate that 3C-SiC avoids cell stress both on DP-NSCs and OECs. Therefore, this study demonstrates that 3C-SiC might be proposed as a valid support in the production of long term implantable biochips having a biocompatibility that overlap with that obtained with other carbon-derived materials. In addition, the synergistic effect of cell transplantation and biomaterial supports implantation could be considered as a promising new insight for nerve injury treatment. In conclusion, our findings highlight the possibility to use as clinical tool for lesioned neural areas Neuronal Stem Cells, NSC-DPSC or OECs plated on 3C-SiC substrate, indicating these strategies as a future perspective for the development of novel cell therapies that would reach from bench to bedside to serve the neuro-degenerated patients.