Human lung cell cytotoxicity of antibacterial-loaded silica nanoparticles

Silica nanoparticles (SiNPs) are extensively used in multiple biomedical and drug delivery applications. We synthesized, characterized, and assessed the role of SiNP size in several human cell types. SiNPs of different sizes (60 nm, 100 nm, and 300 nm) were synthesized via the Sto center dot ber method and their surface was modified by the grafting of ligands (-OH bare, -NH2 amino, and -SH thiol) using organosilane chemistry. SiNPs size, dispersity, and surface were determined by scattering electron microscopy (SEM), hydrodynamic diameter by dynamic light scattering (DLS), and surface grafting by Fourier-transform infrared spectroscopy (FT-IR). Results show no evident cytotoxicity in the tested concentrations and time-courses, up to 30 ppm and 72 h on human cervical (HeLA), lung (A549) and glioblastoma (U251) cells. Fluorescent; rhodamine-labeled SiNPs grafted with positively charged groups were taken up more at greater amounts than unfunctionalized-SiNPs. Rifampicin and vancomycin loading was suitable only in thiolated-SiNPs. SiNPs loaded with rifampicin released the drug and were active against Staphylococcus aureus cultures in a concentration-dependent manner, suggesting that SiNPs could be used for bacterial infections treatment where the localized antibiotic release is desired.