In the field of biomedicine, nanoparticles are already routinely used in the form of contrast agents or drug delivery systems. Due to their size-based properties, the particles can systematically accumulate in the target tissue (e.g. after magnetic targeting) and realize sensitive diagnostic procedures or efficient therapy cascades. In particular, a combination of inorganic nanoparticles (e.g. magnetic iron oxide nanoparticles, FexOyNP) with organic molecules and structures (drugs, antibodies, etc.) provides the opportunity to develop innovative nanoparticulate hybrid systems with multifunctional properties. In the present dissertation, new approaches for the preparation and biomedical application of four different organic-inorganic hybrid nanoparticles were established. For this purpose, indium phosphide/zinc sulfide quantum dots (InP/ZnS-QDs), as well as FexOyNP and gold nanoparticles (AuNP), were synthesized using wet processing techniques. The first hybrid nanoparticle system was prepared by selectively coupling FexOy- and AuNP to an Alzheimer's disease biomarker. In addition to a sensitive ex vivo biomarker detection by surface-enhanced Raman spectroscopy (SERS), detailed process insights were gained by a comprehensive investigation of the synthesis and functionalization steps using a variety of analytical methods. Three more hybrid nanoparticles were prepared by simultaneously encapsulating superparamagnetic FexOyNP with one other component respectively (therapeutic RNA, fluorescent InP/ZnS QDs, or plasmonic AuNP) in organic nanovesicles (niosomes) and applied afterward to various cancer cells lines for an in vitro application. The RNA-loaded superparamagnetic hybrid nanoparticle enabled an efficient RNA-guided chemotherapy through enhanced cellular internalization via magnetic targeting. By encapsulating InP/ZnSQDs and FexOyNP, another nanohybrid was used both as a fluorophore and contrast agent. The fourth hybrid nanoparticle allowed sensitive SERS-based diagnostics after post synthetic magnetic purification. As an administration platform, the niosomes ensured the respective application by protecting the enclosed components from a loss of functionality caused by the different in vitro influences (e.g. acidity). Additionally, a synthesis route using a commercial microfluidic apparatus was developed for the resource-efficient preparation of a niosomal drug delivery system. For the different nanoparticulate formulations, essential physical, chemical, and biological correlations between the used substances, the process chain, and the resulting particle system were analyzed. Consequently, basic synthesis and application strategies for hybrid nanoparticles were derived and discussed.weiterlesen