Effect of the array of amines on the transfection efficiency of cationic peptidomimetic lipid molecules into neural cells

The amino groups in the head group of a cationic lipid play a determinative role regarding the nucleic acid delivery efficiency of the LNP formulated from lipids. Herein, we designed four types of lipid bearing different amine-containing branched head groups to investigate the influence of type and number of amines on the neural cell targeted nuclei acid delivery. Conjugation of an ethylamino group at selected positions of a lysine-based cationic lipid resulted in 4 distinct lipids with 3 (denoted N3 lipid), 4 (denoted N4 lipid), 5 (denoted N5 lipid) and 6 (denoted N6 lipid) amino groups, respectively. Comparative analysis by flow cytometry revealed that the N3 lipid had the highest nucleic acid (plasmid and siRNA) transfection efficiency to neural cell lines (BV2 cells and N2a cells). Furthermore, the N3 lipid mediated delivery of siRNA against Toll Like Receptor 4 (TLR4) into oxygen glucose deprivation (OGD)-treated BV2 cells resulted in remarkable silencing of TLR4, inducing alternative polarization (M2) of the cells. Collectively, our data suggest that the N3 lipid is a promising siRNA delivery agent in neural cells.