Atomic-Force Microscopy and Spectral Characteristics of Hybrid Nanosystems for Photodynamic Therapy in Oncology

The structural-morphological parameters of hybrid nanosystems, which are promising as photo-sensitizers (PS) for photodynamic therapy (PDT), are comparatively studied by atomic force microscopy (AFM), ultraviolet (UV) spectroscopy, photoluminescence (PL) and dynamic light scattering. The nanosys-tems 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 nanoparti-cles/polymer + PD systems (in a solution by means of the molecular optics and PL, and on a surface of a sil-icon 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 sur-face. When the order of the BSA and PD introduction into the system is changed, the nanosystem morphol-ogy 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 emis-sion 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 gen-erate active forms of oxygen and make them promising as the basis for the creation of photosensitive com-pounds for PDT in oncology.