Targeted Delivery of Cisplatin by Gold Nanoparticles: The Influence of Nanocarrier Surface Modification Type on the Efficiency of Drug Binding Examined by CE-ICP-MS/MS

Spherical gold nanoparticles (GNPs), whose unique properties regarding biomedical applications were broadly investigated, are an object of interest as nanocarriers in drug targeted delivery systems (DTDSs). The possibility of surface functionalization, especially in enabling longer half-life in the bloodstream and enhancing cellular uptake, provides an opportunity to overcome the limitations of popular anticancer drugs (such as cisplatin) that cause severe side effects due to their nonselective transportation. Herein, we present investigations of gold nanoparticle–cisplatin systems formation (regarding reaction kinetics and equilibrium) in which it was proved that the formation efficiency and stability strongly depend on the nanoparticle surface functionalization. In this study, the capillary electrophoresis hyphenated with inductively coupled plasma tandem mass spectrometry (CE-ICP-MS/MS) was used for the first time to monitor gold–drug nanoconjugates formation. The research included optimizing CE separation conditions and determining reaction kinetics using the CE-ICP-MS/MS developed method. To characterize nanocarriers and portray changes in their physicochemical properties induced by the surface’s processes, additional hydrodynamic size and ζ-potential by dynamic light scattering (DLS) measurements were carried out. The examinations of three types of functionalized GNPs (GNP-PEG-COOH, GNP-PEG-OCH(3), and GNP-PEG-biotin) distinguished the essential differences in drug binding efficiency and nanoconjugate stability.