Electroporation induced delivery of siRNA-loaded copper sulfide nanoparticles

Abstract

Purpose Irreversible electroporation (IRE) is a new non-thermal ablation technique. It creates both a central ablation zone and a surrounding sub-lethal region. Cancer cells within the sub-lethal region may survive and cause relapse of tumor. The electric field in sub-lethal regions may be sufficient to induce the intracellular delivery of therapeutic agents. Nanoparticles loaded with small-interfering RNA (siRNA) have been successfully used to treat various cancers. In this study, we prepared siRNA-loaded copper sulfide (CuS) nanoparticle system and tested its cellular uptake during electroporation. Materials and Methods Cytotoxicity was quantified by trypan blue staining in HepG2 cell suspensions after electroporation at different power and pulse settings. CuS nanoparticles coated with glycol chitosan (CuS-GC) were loaded with anti-luciferase siRNA via electrostatic interaction. The suspensions of HepG2 or SKOV3.ip1.luc cells were treated with electroporation at 500 V/cm for 90 pulses in the presence of CuS-siRNA. The cellular uptake of nanoparticles and siRNA were monitored by fluorescence microscope. The down-regulation of luciferase was analyzed by luminance assay. Results Electroporation at 500V/cm for 90 pulses did not cause substantial cell death (cell viability = 93.6 ± 4.5%). The CuS-siRNA nanoparticles were 50 nm in diameter. The cellular uptake of CuS nanoparticles was increased by 173% in HepG2 and 52% in SKOV3.ip1.luc cells, compared to controls without electroporation (p Conclusion We developed an in vitro cell model to simulate the peripheral sub-lethal regions of IRE. CuS-siRNA nanoparticles were delivered into carcinoma cells during electroporation and down-regulated the expression of luciferase. Future studies will evaluate the therapeutic efficacy of this combined method in in-vitro and in-vivo experiments after delivery of therapeutic nanoparticles.