Nanotechnology is a rapidly developing field that is under intensive investigation. In comparison to materials on a larger scale, nanomaterials show unique physical, biological, and chemical properties, because of which they show great potential for use in biomedicine. Particularly magnetic nanoparticles have proven to be very promising and are currently being investigated in the diagnostics and treatment of cancer by targeted drug delivery. However, despite their many advantages, the transition of magnetic nanoparticles into clinical use is hindered by their insufficiently investigated safety. To date, it has been established that the safety of magnetic nanoparticles can be significantly influenced by their size, shape, composition, and surface properties, among which the morphology of their surface, precisely the size of the pores on their surface, has recently been highlighted to have an important impact on the safety of magnetic nanoparticles. This thesis aimed to systematically evaluate the impact of surface morphology of silica-coated magnetic nanoparticles on keratinocytes in vitro. The magnetic nanoparticles used in this study were superparamagnetic iron oxide nanoparticle clusters coated with silica with different pore sizes. Additionally, the coating was unmodified or modified with polyethylene glycol molecules. Firstly, we evaluated the magnetic nanoparticles regarding their hydrodynamic size, surface charge, and stability in purified water and the keratinocyte growth medium. Next, we exposed the keratinocytes to magnetic nanoparticles for 24 h to 72 h in a concentration range of 25 µg/mL to 150 µg/mL and evaluated their impact on the keratinocyte morphology, adhesion, and viability in vitro. We determined that the magnetic nanoparticles with larger pores in the coating (pore diameter ~ 69 nm) reduce the viability of keratinocytes in vitro more than nonporous or magnetic nanoparticles with smaller pores in the coating (pore diameter ~ 12 nm). In our experiments we showed that changes in keratinocyte morphology and adhesion after incubation with magnetic nanoparticles were shown to correlate with reduced keratinocyte viability. We further proved that the impurities from the synthesis of the magnetic nanoparticles, such as positively charged surface-active ingredient hexadecyltrimethylammonium bromide, may have a significant effect on the keratinocyte viability in vitro. We have revealed that, in addition to the different surface morphologies of the nanoparticles, other factors could also influence our results, such as the aggregation and deposition of magnetic nanoparticles during incubation with keratinocytes and the interference of magnetic nanoparticles when evaluating the absorbance of the product at a wavelength of 490 nm. With our findings, we were the first to systematically evaluate the impact of the surface morphology of magnetic nanoparticles on cellular response in vitro.
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