Synthesis and characterization of silica-coated superparamagnetic iron oxide nanoparticles and interaction with pancreatic cancer cells

The aim of the study is to investigate the relationship between the physico-chemical properties of superparamagnetic iron oxide nanoparticles (SPIONs) and their cytotoxicity profile in light of their potential biomedical application as nanocarriers for pancreatic cancer treatment. Two types of SPIONs were tested: magnetite nanoparticles (Fe₃O₄ NPs) and silica-coated magnetite nanoparticles (SiO₂-Fe₃O₄ NPs). The physico-chemical properties of the 2 SPIONs were characterized by means of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectrometry (EDS), and Selected Area Electron Diffraction (SAED). Their magnetic properties were quantified as magnetization saturation (Ms) and Remanence. The colloidal stability was investigated by Isoelectric Point Measurements and sedimentation tests. Finally, in vitro characterizations were performed to quantify the half maximal lethal concentration (LC₅₀), by means of High Content Screening Analysis (HCSA), Flow cytometry (FC), and Laser Scanning Confocal Microscopy (LSCM). The obtained NPs present a spherical shape and a dimension between 10 and 20 nm, a superparamagnetic behavior and surface charge in agreement with their surface chemistry. The in vitro tests demonstrate that both NPs induce similar levels of cytotoxicity in a PANC-1 cell model and were internalized, with SiO₂-Fe₃O₄ NPs associated to a slightly higher cellular internalization, probably due to their higher dispersability.