Selenium Nanoparticles: Novel Synthesis, Characterization, Polymer Functionalization, and Cytotoxicity In Vitro

Background: Nanotechnology, a multidisciplinary science, has diverse applications in biology, physics, and medicine. SeNPs have only recently been explored. Understanding how modifications to SeNPs affect toxicity is beneficial for therapeutic applications. This study involves a novel one-pot chemical synthesis of SeNPs using biodegradable precursors, sodium selenite and ascorbic acid, at predetermined molar ratios, followed by polymer modification. Results: All SeNPs were spherical with favorable sizes (<114 nm) and polydispersity indices (PDI < 0.4). Functionalization improved the zeta potential of the SeNPs (−34.4 to 91.1 mV), together with a smaller size and increased PDI. Cytotoxicity was size-, cell-, dose-, and time-dependent. Functionalized SeNPs showed good cell viability at low concentrations, with toxicity at higher concentrations compared to the unmodified SeNPs. SeNPs synthesized using excess sodium selenite exhibited enhanced toxicity, particularly in neuroblastoma cells. SeNPs induced a significant increase in reactive oxygen species, with G1/G0 cell cycle arrest and apoptosis in human embryonic kidney cells, and necrosis and apoptosis in neuroblastoma and cervical carcinoma cells. Conclusion: The physicochemical and toxicity profiles of SeNPs depend on precursor molar ratios and polymer concentration. Hence, studying the released ions and the polymer-core association will enable the personalized synthesis of SeNPs to achieve the desired therapeutic outcomes.