Multilamellar liposomes including cholesterol as carriers of a 1:2 metal complex dye in wool dyeing

Studies are described of the use of multilamellar lipid vesicles (MLV) of defined size (400 nm) containing increasing amounts of cholesterol (CH) as carriers of a 1:2 metal complex dye to untreated wool fibers. We investigate liposomes made from egg phosphatidylcholine (pc) containing the CI Acid Yellow 129 dye (weakly polar 1:2 metal complex dye) at PC:CH molar ratios ranging from 10:0 to 6:4. The total lipid concentration of liposomes and the dye concentration remain constant (1.25 mmol and 1% owf, respectively). The physical stability of these systems is assessed by measuring the mean vesicle size distribution of the vesicle suspensions after preparation and during the dyeing process. Kinetic aspects involving dye adsorption and bonding on untreated wool samples by means of these liposomes are also investigated. This process leads to the controlled exhaustion of dye in wool samples, which depends on the liposome lipid composition. Increasing amounts of CH in bilayers result in a progressive rise in both dye exhaustion and total amounts of dye bonded to wool fibers. The diffusion properties of wool fibers as well as the smoothness of the dyed samples, given as a measure of their handle, also improve.