Currently, gold nanoparticles have found applications in engineering and medical sciences, taking advantage from their properties and characteristics. Surface plasmon resonance, for instance, is one of the main features for optical applications and other physical properties, like high density, that represents the key for cellular uptake. Among other applications, in the medical field, some diseases may be treated by using gene therapy, including monogenetic or polygenetic disorders and infections. Gene adding, suppression, or substitution is one of the many options for genetic manipulation. This work explores an alternative non-viral method for gene transfer by using gold nanoparticles functionalized with organic polymers; two routes of synthesis were used: one of them with sodium borohydride as reducing agent and the other one with chitosan oligosaccharide as reducing and stabilizing agent. Gold nanoparticles conjugated with chitosan, acylated chitosan and chitosan oligosaccharide, were used to evaluate transfection efficiency of plasmid DNA into cell culture (HEK-293). Physical and chemical properties of gold nanocomposites were characterized by using UV-Vis Spectroscopy, ξ - potential, and transmission electron microscopy. Furthermore, the interaction between gold nanoparticles and plasmid DNA was demonstrated by using agarose gel electrophoresis. Transfection tests were performed and evaluated by β-galactosidase activity and green fluorescence protein expression. The percentage of transfection obtained with chitosan, acylated chitosan, and chitosan oligosaccharide were of 27%, 33%, and 60% respectively.

The application of nanoscience and nanotechnology in medicine has been useful in the diagnosis, monitoring, and treatment of many diseases. Gold nanoparticles are commonly used for medical imaging studies, biosensors, drug delivery systems, and gene therapy. It has been reported that nanoparticles coated with specific polymers improve the biocompatibility and stability and decrease the cytotoxicity of the nanoparticles. In this work, we performed transfection studies of gold nanoparticles coated with polyethylene glycol, synthetized by two different methods, in a human embryonic kidney cell culture (HEK 293), by using plasmids pSV-β-Gal and pIRES2-EGFP. In addition, we also evaluated the cell uptake of a fluorescent drug (atorvastatin) using the synthetized gold nanoparticles as carriers. Furthermore, the study of cell viability after the interaction between these cells and the nanoparticles was performed. It was shown that the polyethylene glycol-coated gold nanoparticles presented transfection efficiency and cell uptake greater than 45% in each case. These results suggest that the synthetized gold nanoparticles coated with polyethylene glycol could be used successfully and safely as DNA and drug delivery systems.

No abstract

No abstract

No abstract