Atomic-force microscopy and spectral characteristics of hybrid nanosystems for photodynamic therapy in oncology

Abstract

The structural-morphological parameters of hybrid nanosystems, which are promising as photosensitizers (PS) for photodynamic therapy (PDT), are comparatively studied by atomic force microscopy (AFM), ultraviolet (UV) spectroscopy, photoluminescence (PL) and dynamic light scattering. The nanosystems are nanoparticles of zinc selenide (ZnSe) prepared using the hydrothermal synthesis method, stabilized by various polymer matrices: bovine serum albumin (BSA), polymethacrylic acid (PMAA) and, the second generation PS, photoditazin (PD). Comparison of the nanostructure size characteristics in ZnSe nanoparticles/polymer + PD systems (in a solution by means of the molecular optics and PL, and on a surface of a silicon wafer in air by means of AFM) at the same concentration of reagents in the reaction mixture shows that nanocluster sizes in the solution are two times larger than those in a thin film prepared on the substrate surface. When the order of the BSA and PD introduction into the system is changed, the nanosystem morphology changes strongly (nanocluster sizes and shape), which is due to the competition of the polymer stabilizers during complex formation with ZnSe nanoparticles. Analysis of the photoluminescence excitation and emission spectra of PD and the triple-system aqueous solutions shows that the ZnSe/BSA nanostructures do not suppress PD photoluminescence in the triple system ZnSe/BSA + PD, i.e., do not affect their ability to generate active forms of oxygen and make them promising as the basis for the creation of photosensitive compounds for PDT in oncology.