Ultrasound-enhanced gene delivery to alfalfa cells by hPAMAM dendrimer nanoparticles

Abstract

Cationic polyamidoamine (PAMAM) dendrimers are highly branched nanoparticles with unique molecular properties,which make them promising nanocarriers for gene delivery into cells. This research evaluated the ability of hyperbranched PAMAM(hPAMAM)-G2 with a diethylenetriamine core to interact with DNA, its protection from ultrasonic damage, and delivery to alfalfa cells.Additionally, the effects of ultrasound on the efficacy of hPAMAM-G2 for the delivery and expression of the gusA gene in the alfalfacells were investigated. The electrophoresis retardation of plasmid DNA occurred at an N/P ratio (where N is the number of hPAMAMnitrogen atoms and P is the number of DNA phosphorus atoms) of 3 and above, and hPAMAM-G2 dendrimers completely immobilizedthe DNA at an N/P ratio of 4. The analysis of the DNA dissociated from the dendriplexes revealed a partial protection of the DNA fromultrasound damage at N/P ratios lower than 2, and with increasing N/P ratios, the DNA was better protected. Sonication of the alfalfacells in the presence of ssDNA-FITC-hPAMAM increased the ssDNA delivery efficiency to 36%, which was significantly higher thanthat of ssDNA-FITC-hPAMAM without sonication. Additionally, the efficiency of transfection and the expression of the gusA gene weredependent on the N/P ratio and the highest efficiency (1.4%) was achieved at an N/P ratio of 10. The combination of 120 s of ultrasoundand hPAMAM–DNA increased the gusA gene transfection and expression to 3.86%.