Dendrigraft poly-L-lysine (d-PLL) coated gold nanoparticles in water for siRNA delivery to prostate cancer cells

Herein we describe a simple method for the synthesis of dendrigraft poly-L-lysine (d-PLL) coated different sizes gold nanoparticles in water (AuNPs-d-PLL) as potential to delivery vehicles of siRNA to PC-3 prostate cancer cells. AuNPs-d-PLL with diameters ranging between 50-120 nm have been synthesised in aqueous solutions using d-PLL (7 KD) as a capping ligand, and ascorbic acid as a reducing agent. The size of the resulting AuNPs was found to depend on several parameters (i.e. the concentrations of the gold salt, ascorbic d-PLL and temperature). The obtained AuNPs-d-PLL were characterized using UV-visible spectroscopy (UV-vis), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS). The ability to PEGylate the AuNPs-d-PLL with SH-PEG-OCH₃ and SH-PEG-Folate was demonstrated via DLS and zeta potential mesurements, their capacity to complex siRNA was verified (DLS, gel electrophoresis), and transfer of AuNPs-d-PLL-PEG-FA.siRNA to PC-3 cells was investigated.