Abstract
In the present study, nonionic surfactant vesicles (niosomes) formulated with Span 20, cholesterol, and novel synthesized spermine-based cationic lipids with four hydrocarbon tails in a molar ratio of 2.5:2.5:1 were investigated as a gene carrier. The effects of the structure of the cationic lipids, such as differences in the acyl chain length (C14, C16, and C18) of the hydrophobic tails, as well as the weight ratio of niosomes to DNA on transfection efficiency and cell viability were evaluated in a human cervical carcinoma cell line (HeLa cells) using pDNA encoding green fluorescent protein (pEGFP-C2). The niosomes were characterized both in terms of morphology and of size and charge measurement. The formation of complexes between niosomes and DNA was verified with a gel retardation assay. The transfection efficiency of these cationic niosomes was in the following order: spermine-C18 > spermine-C16 > spermine-C14. The highest transfection efficiency was obtained for transfection with spermine-C18 niosomes at a weight ratio of 10. Additionally, no serum effect on transfection efficiency was observed. The results from a cytotoxicity and hemolytic study showed that the cationic niosomes were safe in vitro. In addition, the cationic niosomes showed good physical stability for at least 1 month at 4°C. Therefore, the cationic niosomes offer an excellent prospect as an alternative gene carrier.