Antibacterial reactive liposomes encapsulating coupled enzyme systems

Liposomes have been prepared from phospholipid mixtures of dipalmitoylphosphatidylcholine (DPPC) and phosphatidylinositol (PI) encapsulating the enzymes chloroperoxidase (CPO) and lactoperoxidase (LPO) in combination with glucose oxidase (GO) by both extrusion (VET) and/or reverse phase evaporation (REV). The liposomes were characterised in terms of the protein content and activity of the encapsulated enzymes. The antibacterial activity of these reactive liposomes arises from hydrogen peroxide and oxyacids produced in the presence of the substrates glucose and chloride or thiocyanate ions. The liposomes were targeted to biofilms of Steptococcus gordonii, an oral bacterium and their antibacterial activity was measured both as a function of liposome-biofilm incubation time and incubation time with the substrates. Bacterial inhibition increases with both liposome-biofilm and substrate-biofilm incubation time and with the extent of enzyme encapsulation. The reactive liposomes also display antibacterial activity in the presence of saliva. The reactive liposomes have potential value in the context of oral hygiene. (C) 1998 Elsevier Science B.V. All rights reserved.