Introduction: High-intensity pulsed electromagnetic fields (HI-PEMF) can be used to trigger contactless permeabilization of the plasma membrane similar to electroporation (EP). The permeabilization efficiency and gene delivery by HI-PEMF in vitro are currently inferior to EP. It was suggested that the methodology can be improved with conductive gold nanoparticles (AuNPs), which are reported to amplify the induced electric field in close proximity to the cell membrane.
Objectives: Therefore, in this work, we have studied different NPs, which varied in material/conductivity (gold and silica), size (10-50+ nm), shape (i.e., round and rods), concentration (50-200 µg/mL), and functionalization (pegylated or not), and combined them with HI-PEMF (6.7 T × 100 pulses, 1 Hz).
Methods: The normal Chinese hamster ovary cell line (CHO) and the cancer human urinary bladder’s transitional carcinoma cell line (T24) were used as a model. We have characterized cell membrane permeabilization using propidium iodide (PI) and the efficacy of gene delivery using pEGFP-N1.
Results: Larger NPs and higher NP concentrations resulted in up to a 10% increase in membrane permeability. In contrast, semispherical and rod-shaped AuNPs did not further enhance permeabilization efficiency. Gene delivery efficiency increased from 3% in control samples to 6% in the presence of 50 nm AuNPs. Overall, CHO cells were more susceptible to HI-PEMF-induced effects than T24 cells.
Conclusions: This study shows the potential to increase gene delivery efficacy by combining HI-PEMF treatment with conductive NPs. However, it was concluded that the HI-PEMF-induced effects are highly dependent on the cell line, NP type, and concentration and therefore require further investigation.
