Evaluation of asymmetric immunoliposomal nanoparticles for cellular uptake

Effective and targeted in vivo delivery of polynucleotide therapeutics is the key for the treatment of many diseases. Asymmetric immunoliposomes can be used as vehicles to deliver polynucleotides effectively because the two leaflets of the bilayer can have different compositions, which enhance the delivery capacity. The formation and in vitro cellular uptake of asymmetric immunoliposomes containing polynucleotide cargoes were studied here. Maleimide-functionalised DSPE-PEG (2000) were incorporated into the outer leaflet to produce asymmetric liposomes capable of covalently attaching antibodies. Thiolated antibodies from both human and rabbit origin were conjugated to produce asymmetric pendant-type immunoliposomes that retain their specificity towards detection antibodies through the formation process. Human IgG-conjugated asymmetric immunoliposomes were readily internalised (>20 per cell) by macrophage, HEPG2, and CV-1 monkey kidney cells. The cells internalised the liposomal nanoparticles by the endocytic pathway. The immunoliposome-encapsulated endosomes were intact for at least 5 days and sequestered the plasmid from expression by the cell.