Effects of silica nanoparticles with varied physicochemical properties on the survival and functionality of saturated macrophages

Silica nanoparticles (SNPs) have shown potential as nanocarriers in diagnostic, imaging, and drug delivery applications. To use SNPs for systemic drug delivery, it is important to have a detailed understanding of how these particles interact with the mononuclear phagocytic system (MPS). Whether or not SNPs may saturate the macrophages, thereby influencing their function and impairing innate immune responses, remains poorly understood. In this work, we defined macrophage saturation using RAW 264.7 macrophages as a model and studied four SNPs with variations in size and porosity. We further explored the downstream effects of SNP uptake by macrophages, including apoptosis/necrosis, cell cycle progression, membrane integrity, and phagocytic activity. The data demonstrate that SNPs do not alter major cellular functions at their respective nontoxic, saturating concentrations.