Gold nanoparticle-enhanced electroporation for leukemia cell transfection

Electroporation serves as an attractive nonviral gene delivery approach for its effectiveness, operational simplicity, and no restrictions of probe or cell type. The commercial electroporation systems have been widely adopted in research and clinics with protocols usually compromising appropriate transfection efficiency and cell viability. By introducing gold nanoparticles (AuNPs), we demonstrated greatly enhanced performance of electroporation from two aspects: the highly conductive, naked AuNPs help reduce the potential drop consumed by the electroporation solution so that the majority of the applied voltage of an electric pulse is truly imposed on cells with enhanced field strength; AuNPs with targeting ligands (e.g., transferrin-AuNPs or Tf-AuNPs) are bound to the cell membrane, working as virtual microelectrodes to create pores on cells with limited opening area while from many different sites. The addition of AuNPs during electroporation therefore benefits not only quicker recovery and better survival of cells but also more efficient uptake of the subjected probes. Such enhancement was successfully confirmed on a chronic myeloid leukemia cell line (i.e., K562 cells) in both a commercial batch electroporation system and a homemade flow system with pWizGFP plasmid DNA probes. The efficiency was found to be dependent on the size, concentration, and mixing ratio of free AuNPs/Tf-AuNPs. An equivalent mixture of free AuNPs and Tf-AuNPs exhibited the best enhancement with the transfection efficiency increase of two to threefold at a minimum sacrifice of the cell viability.