Preparation Of Lipid Nanoparticles For Gene Transfection

Lipid nanoparticles include solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). It is a novel carrier for targeted and controlled drug delivery.In this research, ethanol was selected as the organic solution and poloxamer 188 was chosen as the liquid solution. Monosterain (MS) was used to prepare solid lipid nanoparticles. Nanostructured lipid carriers were then developed based on the SLN by incorporating liquid lipids oleic acid (OA) in the solid core of the particles.PEG2000-SA was added to form PEG-SLN.The average size of solid lipid nanoparticles prepared by the aqueous solvent diffusion method was below 100 nm. SLN has good cellular uptake, and the uptake capacity was enhanced when adding OA or PEG.The SLN/protamine/DNA or NLC/protamine/DNA ternary nanoparticles were prepared by mixing appropriate amount of SLN or NLC to the protamine/DNA binary complex for gene delivery research.In the system of SLN/protamine/DNA ternary nanoparticles, the average hydrodynamic diameter of ternary nanoparticles increased from 188.50±0.26 nm to 259.33±3.44 nm, and the zeta potential increased from 25.50±3.30 mV to 33.40±2.80 mV when the weight ratio of SLNs to DNA increased from 16/3 to 80/3. The ternary nanoparticles composed of SLNs with 15 wt% ODA (with a 50/3 weight ratio of SLNs to DNA) showed the best transfection efficiency (26.13±5.22 %) in the presence of serum. It was found that the cellular uptake of ternary nanoparticles was better than that of the SLNs/DNA system and the protamine/DNA binary complex. Comparing with lipofectamine ^TM2000/DNA complex, the ternary nanopartciles presented relative durative and stable gene transfection.OA-NLC/protamine/DNA or PEG-SLN/protamine/DNA ternary nanoparticles were then prepared by combining the protamine/DNA binary complex with OA-NLC or PEG-SLN. The ternary nanoparticles had an average size about 200 nm and were all negatively charged. Gene transfection efficiency was improved by increasing OA content in lipid nanoparticles. Results of cellular uptake showed that the uptake ability of lipid nanoparticles was enhanced by increasing the OA content. Lipid nanoparticles with 20 wt% OA/protamine/DNA ternary nanoparticles (w/w/w, 65:6:3) showed the best and the most durable gene transfection even in the presence of serum. PEG-SLN had a better cellular uptake than SLN, and the cellular uptake ability increased with the addition of more PEG. PEG-SLN/protamine/DNA nanoparticles had stronger transfection efficiency with serum than that without serum on HEK293 cell lines.