(618e) Gold Nanoparticle Electroporation Enhanced Polyplex Delivery

Non-viral delivery strategies have been widely developed to serve as favorable alternative in cell therapy for their low toxicity and immunogenicity. However, they still suffer some unsatisfied performance (e.g., low cellular uptake, high cytotoxicity, and/or low efficiency). We hypothesize that appropriate combinations of some non-viral delivery approaches could help improve their overall therapy performance. In this study, we combined polyplex and electroporation to improve the delivery of DNA and RNA based probes. Specifically, polyplex (i.e., complex of cationic polymers and DNA/RNA probes) are fixed on the surface of gold nanoparticles (AuNPs) to avoid high cytotoxicity of free cationic polymers when dissociated in cell post internalization. AuNPs also serve as homogeneous probe carrier to help produce AuNP-polyplex complex with more uniform in size. Electroporation helps the quick and direct internalization of complex without the slow and inefficient endocytosis route. The presence of AuNPs further enhances electroporation performance from two aspects: free AuNPs help reduce the electroporation solution resistance for its high conductivity, leading to enhancement of the actual pulse strength on cells; transferrin grafting AuNPs (Tf-AuNPs) bound to TfR receptors on cell membrane and served as virtual microelectrodes to localize the electric fields.  The delivery efficiency was evaluated with leukemia cells with both DNA plasmids (e.g., pGFP & pLuc) or siRNA molecules (e.g., siRNA & miRNA). Compare to traditional polyplex, AuNPs-polyplex have more homogeneous morphology, as confirmed with AFM and dynamic light scattering measurements. The transfection enhancement to plasmid DNA was shown 1.5~2 folds improvement with no significant increase of toxicity is observed. Similar effectiveness was also achieved in siRNA and miRNA delivery. Such a combination of physical and chemical delivery concept may stimulate further exploration in the delivery of various therapeutic materials for both in vitro and in vivo applications.