Nanoparticles and nanofibers have shown significant potential for their use in biomedicine, including drug delivery, tissue regeneration, wound care, diagnostics, and theranostics. Among different types of nanoparticles, magnetic nanoparticles (MNPs), based on iron oxide, most commonly magnetite (Fe3O4) or maghemite (γ-Fe2O3), have recently attracted attention as they show superparamagnetic properties at sizes < ~20 nm. In doctoral dissertation, we addressed the key challenges in the development of MNPs, including improvement of the MNP dispersion stability, drug loading into MNP shell, and MNP safety. To improve the physical stability of MNPs, we transformed MNP dispersions into a dry form, adopting the electrospinning method as an innovative approach to prepare a non-powdered product in the form of hydrophilic nanofibers with up to 65% (w/w) MNPs, which enabled rapid, easy, and efficient reconstitution of MNPs. Furthermore, we successfully incorporated four different drugs into hydrophilic nanofibers and demonstrated that their physicochemical properties significantly affect the nanofiber properties. We developed a drug-loading method for MNPs with a mesoporous silica shell and dry the prepared MNP formulation using electrospinning to prevent MNP aggregation and premature drug release from MNPs into the dispersion during storage. Thus, we managed to prepare homogenous nanofibers with ~20.0% (w/w) of MNPs and ~4.2% (w/w) of the drug. We conducted the first systematic evaluation of the influence of silica-coated MNP surface morphology on the biological response of cells in vitro and demonstrated that MNPs with smaller pore size on the surface are safer than MNPs with bigger pore size. With developed innovative technological approaches, we opened new possibilities for future investigations and addressed some crucial technological challenges in the development of nanoparticles. With our findings, we contributed our small piece to the mosaic of knowledge, which is crucial for ensuring safe, effective, and quality MNPs for use in various biomedical applications.
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