Sessions

Gold nanoparticles (AuNPs) are well characterized nanomaterials used in diagnostics, drug delivery, and therapy; however, their bioaccumulation is strongly influenced by the particle physicochemical characteristics and target cell phenotype. The present study was designed to investigate the type- and size-dependent uptake and short-term cytocompatibility of spherical AuNPs (nominal diameters 13 nm and 20 nm) in Madin–Darby canine kidney (MDCK) epithelial cells and primary neonatal mouse cardiac fibroblasts. Cells were exposed for 24 h to AuNPs at concentrations of 0.1, 1, and 10 µg/mL. Post-exposure cell viability was quantified using the Neutral Red assay. Cellular Au uptake was evaluated by bulk inductively coupled plasma mass spectrometry (ICP-MS) in addition to single-cell ICP-MS (scICP-MS) for 20 nm particles.

Overall, AuNP exposure induced no significant reduction in cell viability compared with untreated controls. Bulk ICP-MS revealed clear cell-type and size dependent differences: Au accumulation in MDCK cells was almost tenfold higher than in cardiac fibroblasts for 13 nm particles, and fivefold higher for 20 nm particles. Particle internalization was dose-dependent, and cellular accumulation was higher with 20 nm particles than with 13 nm particles. By scICP-MS in 20 nm particles lower doses (0.1 and 1 µg/mL) resulted in comparable intracellular particle distributions in both cell types, whereas with 10 µg/mL a significant uptake, approximately twofold higher, was seen in MDCK cells. In the heart fibroblast cell experiment the chemical fixation (2% PFA) was found to be critical to preserve cellular integrity.

In conclusion, AuNP internalization efficiency depends on both, cellular type and particle diameter, with renal epithelial cells exhibiting substantially higher mass uptake than cardiac fibroblasts. Furthermore, scICP-MS offers distinct, cell-resolved insights into uptake variability, provided sample fixation protocols are optimized.