TARGETING AND DELIVERY OF BACTERICIDE TO ADSORBED ORAL BACTERIA BY USE OF PROTEOLIPOSOMES

Proteoliposomes having surface-bound succinylated concanavalin A (s-co nA) have been prepared from a range of phospholipid mixtures by sonica tion (SUV) and reverse phase evaporation (REV) covering a range of siz e (weight-average diameter (d(w)BAR)) from approx. 35 to 310 nm and we ight-average number of protein molecules per liposomes (P(w)BAR) from approx. 50 to 3000. The targeting of the proteoliposomes to adsorbed b iofilms of the bacteria Streptococcus sanguis and Streptococcus mutans has been assessed from the extent of inhibition of an enzyme-linked i mmunosorbent assay (ELISA) for bacterial cell surface antigens. The su rface-bound lectin enhances targeting relative to 'naked' liposomes of comparable concentration by factors of 2-50 depending on the liposoma l lipid composition and P(w)BAR. The effect of the bactericide Triclos an' on the thermal properties and permeability characteristics of lipo somes has been studied. At and above a molar ratio of Triclosan(R) to lipid of 0.6, Triclosan(R) eliminates the gel to liquid-crystalline ph ase transition in dipalmitoylphosphatidylcholine (DPPC) containing lip osomes and increases the bilayer permeability of both liposomes and pr oteoliposomes to D-glucose. The proteoliposomes have been used to deli ver Triclosan(R) to S. sanguis biofilms and the inhibition of growth o f the bacteria after treatment with liposomally delivered Triclosan' h as been determined using a microtitre plate re-growth assay and compar ed with growth inhibition by 'free' Triclosan(R). It is shown that for short exposure times (1 to 2 min) proteoliposomally delivered Triclos an' is a more effective growth inhibitor than free Triclosan(R). The r esults are discussed in terms of the targeting, retention and subseque nt release of Triclosan' into the bacterial biofilms.