Revistes Catalanes amb Accés Obert (RACO)

Liposomas unilamelares de fosfatidilcolina como vehículos de colorantes de tipo complejo metálico 1:2

Alfonso De la Maza Ribera, Sebastià Serra, Meritxell Martí, Ma. Luisa Coderch Negra, Albert Mª Manich i Bou, José Luis Parra

Resum


Studies on the use of large unilamellar liposomes (LUV) of defined size (400 nm) as carriers of a 1:2 metal complex dye to untreated wool fibres are described. We investigated liposomes made from egg phosphatidylcholine (PC) containing the C.I. Acid Yellow 129 dye (weakly polar 1:2 metal complex dye). The total lipid concentration of liposomes varied from 0.56 % to 6.81 % o.w.f (corresponding to 0.25-3.0 mmol/l) and the dye concentration from 0.1 to 1.0 % o.w.f.. The physical stability of these systems was 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 were also investigated. This process led to the controlled exhaustion of dye in wool samples, which was dependent on the PC concentration and on the PC/dye weight ratio in liposomes. Thus, at a constant dye concentration (1 % o.w.f.) a progressive rise in the dyebath exhaustion took place as the PC concentration in bilayers increased reaching a maximum for 3.97 % o.w.f. (corresponding to 1.75 mmol/l), which corresponded to a PC/dye weight ratio of about 4. Additional amounts of PC in bilayers resulted in a progressive fall of this parameter. However, the total percentage of dye bonded to the fibre was reached at the highest PC concentration. A maximum in both the dyebath exhaustion and the percentage of bonded dye was also attained at the same PC/dye weight ratio when varying the dye concentration in liposomes at a constant PC concentration (2.27 % o.w.f.).

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