Comparison of cytotoxicity, radiosensitizing properties and cellular uptake of palladium nanoparticles stabilized with commercial chitosan and chitosan isolated from honey bees

Recently, there has been increasing interest in the use of biocompatible natural polymers, especially polysaccharides, in the synthesis of nanoparticles (NPs). The undoubted advantages of such carbohydrate polymers as components of NPs include their well-defined chemical structure, biodegradability and widespread availability. This study reported the development of an effective method for the synthesis of biocompatible chitosan-stabilized palladium nanoparticles (Pd NPs). For this purpose, both commercial chitosan and chitosan isolated from honey bee corpses were used. Spherical ⁓ 20 nm Pd NPs I and ⁓ 40 nm flower-like Pd NPs II were obtained when commercial chitosan and chitosan isolated from bees (green synthesis method) were used, respectively. In vitro studies on selected glioblastoma cell lines (LN229 and U118) indicated that both types of Pd NPs have similar cytotoxicity, however Pd NPs I are characterized by improved radiosensitizing properties compared to Pd NPs II. Furthermore, real-time holotomographic observations of cells interactions with Pd NPs showed that (for the same concentrations) Pd NPs II generate more visible changes in cell morphology, including their flattening, which is particularly observed for LN229 cells. In summary, Pd NPs I seem to be more promising nanosystems for biomedical applications as radiosensitizers than Pd NPs II.