Intracellular Delivery of Drug & DNA with a-Synuclein-coated Gold-Nanoparticles

Abstract

Alpha-Synuclein, the protein related with Parkinson' s disease, has been reported that it can penetrate the cell membrane. Herein, we achieved successful intracellular delivery of drugs and gene using this membrane penetrating characteristic of alpha-synuclein. First, alpha-synuclein was immobilized on the gold-nanoparticles (AuNPs) by the cysteine mutant at the C-terminal and this binding orientation showed the highest delivery efficiency to the nucleus. Also, this alpha-synuclein-coated AuNP formed complexes with DNA and mesoporous silica nanoparticle (MSN) at acidic pH and our in vitro studies showed high intracellular uptake of these complexes into the mammalian cells. The MSN-AuNPasyn complex was constructed in which the pores of MSN were blocked by AuNPasyn thus preventing the leaking of the loaded drugs. We called this complex as Particles-on-a-particle (PoP) and the cells treated with Doxorubicin (DOX) loaded PoP showed severe cytotoxicity level implicating that the drugs were successfully delivered. Another complex constructed was the DNA-AuNPasyn complex for the purpose of gene delivery. A complex of GFP expressing plasmid and AuNPasyn was treated to the cells and by measuring the fluorescence intensity we determined the gene transfection efficiency. In comparison to lipofectamine, this AuNPasyn system showed significantly faster transfection rate. We suggest that AuNPasyn as the novel cell internalization agent for delivering drugs and gene. In future studies, we expect to evaluate the nucleus localization signal within the alpha-synuclein sequence.