Lipid-based Biomimetics in Drug and Vaccine Delivery

Abstract

Lipids provide adequate matrixes for supporting important biomolecules (proteins, DNA, oligonucleotides and polysaccharides) on model surfaces (latex, silica, silicon wafers, selfassembled monolayers, metals, polymers, insoluble drugs, biological cells and viruses). For example, biomolecular recognition between receptor and ligand can be isolated and reconstituted by means of receptor immobilization into supported lipidic bilayers on silica. This is an overview on novel lipid-based assemblies for drug and vaccine delivery. Especial emphasis will be on assemblies produced from the cationic, synthetic and unexpensive lipid dioctadecyldimethylammonium bromide (DODAB). DODAB vesicles interacted with negatively charged prokaryotic or eukaryotic cells with high affinity changing the cell surface charge from negative to positive and reducing cell viability. DODAB effects on cell viability (bacteria, fungus and cultured mammalian cells) revealed its high antimicrobial activity and differential cytotoxicity in vitro. DODAB bilayer fragments were combined with drugs, biomolecules or particles producing novel lipid-based biomimetics to deliver difficult drugs or design vaccines. Hydrophobic drug granules or aggregated recombinant antigens became well dispersed in water solution via lipid adsorption on drug particles as nanocapsules or protein adsorption onto supported DODAB bilayers. In other instances, hydrophobic drug molecules were attached as monomers to borders of lipid bilayer fragments yielding drug formulations effective in vivo at low drug-to-lipid-molar ratio. Cationic biomimetic particles from silica or latex covered with one cationic lipid bilayer proved effective for adsorption, presentation and targeting of biomolecules in vivo. Thereby antigens were effectively presented to the immune system by particles at defined and controllable sizes. The problem of delivering drugs, antigens or biomolecules to their targets in vivo is central and multidisciplinary and biomimetic assemblies are a major asset to improved and less toxic drug and vaccine delivery.