Gold Nanoparticles-Enhanced Gene Transfer Driven by MHz-Frequency Nanosecond Pulsed Electric Fields

Electroporation can be used as an effective non-viral gene delivery method, while the application of conductive nanoparticles (NPs) with pulsed electric fields (PEFs) may increase treatment efficacy due to local field amplification in close proximity to the cell plasma membrane. In this work, we have employed 100 ns and 300 ns pulses (9-17 kV/cm), which were delivered in bursts (n = 100) and predefined inter-pulse delays (100-900 ns), which enabled successful gene delivery (4.7 kbp; p-EGFP-N1) using pulses as short as 100 ns, which previously was considered impossible. As a model, a murine breast cancer cell line (4T1) was used. It was shown that sub-microsecond pulses (i.e., 300 ns) can be effective for gene delivery, whereas 100 ns pulses are several-fold inferior, yet still trigger successful gene transfer (>10% of cells being electrotransfected). In order to increase the efficacy of the treatment, we used gold nanoparticles (AuNPs; the diameter of 13 nm), which allowed us to achieve electrotransfection efficacy several-fold for both sub-microsecond and microsecond protocols (1.2 kV/cm × 100 µs × 8 pulses at 1 Hz). The results suggest high potential applicability of conductive nanoparticles in future translational or clinical research involving electroporation and gene transfer.