Abstract:

Based on our findings and those of other investigators, we postulate that there are a variety of possibilities for promoting neuronal regeneration using SPIOs. Compared to in vivo testing, our in vitro studies do have some limitations, e.g., they do not permit the assessment of three-dimensional network interaction. However, in vitro SPIO studies are certainly necessary to clarify particle- and cell type-induced effects that exclude external stimuli. In addition, the benefits of nanoparticles must be weighed against their potential adverse effects. In particular, it is essential to refer more to physicochemical features including size, surface coating and SPIO charge as these strongly influence e.g. their degradation, target specificity, and long-term storage. Furthermore, SPIOs may induce the release of mediators for inflammation, apoptosis and oxidative stress through microglial and astrocyte activation. The complex interaction of signaling molecules at both the inter- and intracellular levels is challenging for precisely determining SPIO-induced effects. We need a deeper understanding of the molecular mechanisms induced by SPIOs to develop safety guidelines for their clinical application. Nevertheless, nanoparticles have already proven to be powerful tools for basic research and offer many advantages. This trend is expected to expand in terms of their fields of application.