Interaction of polyelectrolyte coated beads with phospholipid vesicles

Colloidal particles coated by polyelectrolyte multilayers of alternatingly positive and negative charge are shown to interact strongly with lipid vesicles. We have studied two cases: (i) the interaction between beads and small unilamellar vesicles (vesicles diameter smaller than the particles one), where we found evidence for coating of the beads with lipid bi- or multilayers in the form of an increase in bead diameter and changes in the beads surface potential; (ii) the interaction of beads with giant vesicles (vesicles larger than the particles), where we observed by fluorescence microscopy the spreading of the vesicle on the bead manipulated with an optical tweezer. Giant fluctuations of the vesicles are suppressed due to the adhesion of the vesicle to the bead and direct observation of the coating process shows that lipid coverage is not limited to the direct vesicle-bead contact area, but is rather extended to the entire bead. To cite this article: A. Fery et al., C. R. Physique 4 (2003). [Copyright &y& Elsevier]