[Preparation of plasmid nanoemulsion and its character determination by anion exchange chromatography method]

Nanoemulsion-encapsulated lzp3 DNA vaccine (pCDNA3-Aat-COMP-lzp3-C3d3, lzp3) was prepared, and its quality was evaluated. The interfacial emulsification method was employed to make the nanoemulsion-encapsulated plasmid, and its sizes and distribution were detected by electron microscope. Anion exchange chromatography was used to separate the nanoemulsion from the plasmid based on the charge characteristics of plasmid. The determination method for encapsulation efficiency of the plasmid nanoemulsion was established by anion exchange chromatography. The results indicated that the average size of the plasmid nanoemulsion is (23 +/- 10) nm, and the encapsulation efficiency is 80.5%. The separation and determination conditions of nanoemulsion-encapsulated plasmid was as follows: eluent buffer was 0.05 mol/L Tris-HCl solution at a flow rate of 0.7 mL/min, while detection wavelength for plasmid was 260 nm, the temperature of column was maintained at 30 degrees C, and injection volume was 2mL. On this condition, nanoemulsion and plasmid can be separated on the column of anion exchange chromatography significantly. This method is simple, sensitive and reproducible with respect to good linearity in the range of 0.05-0.80 mg/mL (r = 0.9983), which can be applied to determine the entrapment efficiency of nanoemulsion-encapsulated plasmid.