Influence of microenvironmental viscosity on the cellular uptake of Fe3O4 nanoparticles and their anticancer effect.

Viscosity is a characteristic property of extracellular microenvironments, and it varies among cancer tissues. Although internalized magnetic nanoparticles are crucial for magnetic hyperthermia, the influence of microenvironmental viscosity on their cellular uptake remains elusive. In this study, the effect of microenvironmental viscosity on the cellular uptake of magnetic nanoparticles and the efficiency of magnetic hyperthermia were investigated by culturing colorectal cancer cells in media of different viscosities. Results showed that the cellular uptake of magnetic nanoparticles significantly decreased with increasing microenvironmental viscosity, which further decreased the intracellular heating effect of magnetic nanoparticles. Furthermore, the proportion of apoptotic cells induced by magnetic hyperthermia was significantly reduced in high viscosity microenvironments, and the most viscous microenvironment exhibited the lowest apoptosis rate. This study revealed the important role of microenvironmental viscosity in regulating the cellular uptake of magnetic nanoparticles and the efficiency of magnetic hyperthermia, which provides a novel perspective for optimizing the application of magnetic hyperthermia in anticancer therapy.