THE USE OF PHOSPHOLIPID LIPOSOMES FOR TARGETING TO ORAL AND SKIN-ASSOCIATED BACTERIA

Phospholipid (dipalmitoylphosphatidylcholine (DPPC) plus phosphatidyli nositol (PI)) proteoliposomes with surface bound lectins (succinylated concanavalin A (s con A) and wheat germ agglutinin (WGA)) have been p repared covering a range of size and surface density of lectin. Negati vely charged phospholipid liposomes from DPPC PI mixtures covering a r ange of PI mole % and positively charged liposomes from DPPC-cholester ol-stearylamine (SA) mixtures covering a range of SA mole % have been prepared. The targeting of the liposomes and proteoliposomes to a rang e of oral and skin-associated bacterial biofilms has been investigated . The oral bacteria Streptococcus mutans and gordonii and the skin-ass ociated bacterium Corneform hofmanni can be targeted with s con A bear ing proteoliposomes while the skin associated bacterium Staphylococcus epidermidis can be targeted with WGA bearing proteoliposomes. Both or al and skin-associated bacteria can be targeted with positively charge d liposomes although the extents of adsorption to the biofilm are low except for Staphylococcus epidermidis. In the case of negatively charg ed liposomes targeting is critically dependent on the PI content of th e liposomes and for all the bacteria studied optimum levels PI for tar geting have been found. The adsorption of the oral bacterium Streptoco ccus gordonii to immobilised monolayers having the optimum PI level fo r adsorption has been studied by total internal reflection microscopy (TIRM). Both the phospholipid and proteoliposomes have been used to de liver the bactericide Triclosan(R) to biofilms. All the systems studie d inhibited bacterial growth to varying degrees. The proteoliposomes a nd the DPPC-PI liposomes containing low levels of Triclosan(R) inhibit ed bacterial growth more effectively than the equivalent levels of fre e bactericide.