Abstrakt

Anticancer drug conjugates with metal nanoparticles are in the centre of research interest due to the promising application potential in modern medicine. It was proved that plasmonic metal nanoparticles are not only drug carriers and amplifiers of biological effect but also sensors for tracking the fate of the drug in organisms and cells. The formation of drug conjugates with gold (AuNPs) and silver nanoparticles (AgNPs) are widely described in the literature whereas less attention was paid on the formation of anticancer drug conjugates with platinum nanoparticles (PtNPs). These studies were conducted to verify the main hypothesis that conjugates of erlotinib (ERL), belonging to drugs used in non-small cell lung cancer (NSCLCs) treatment, with PtNPs can be formed in electrostatically-driven self-organization process. PtNPs were prepared using a seed-mediated growth method. The micrographs obtained from transmission (TEM) and scanning (SEM) electron microscopy revealed that PtNPs exhibited quasi-spherical shape and an average size equal to 108±11 nm. The stability of PtNPs under controlled pH and ionic strength was determined by dynamic (DLS) and electrophoretic (ELS) light scattering. The formation of ERL-PtNP conjugates was carried out under mild acidic conditions, at pH 4.9 and ionic strength 7 × 10−3 M. The spectroscopic analysis of formed conjugates was performed with the use of surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared adsorption spectroscopy (SEIRA).The spectroscopic investigation was carried out for positively charged conjugates. The performed SERS and SEIRA studies indicate that the prepared PtNPs provide effective surface enhancement in visible and infrared regions, respectively, ensuring the possibility to perform detailed characterization of the adsorption process on these metal nanostructures. The considered ERL indicates strong interaction with the PtNPs mainly through the quinazoline and the amino moieties. Also, the ethylene bridge takes part in the conjugates formation, while methoxy moiety and phenylacetylene ring remain at a certain distance from the metal surface. The comparison of obtained results with available literature data showed that the adsorption pattern of ERL strongly depends on the type of plasmonic nanoparticles because the phenylacetylene ring of ERL plays a crucial role in the formation of conjugates with AuNPs and AgNPs. Based on these findings, the chemical structure of ERL in the formed conjugates was proposed. It was concluded that the stable ERL-PtNP conjugates can exhibit comparable electrokinetic properties with ERL conjugates with AuNPs and AgNPs while the chemical structure of ERL layer on nanoparticle surface strongly depends on the plasmonic metal type.