title: Mannose-Escherichia coli interaction in the presence of metal cations studied in vitro by colorimetric polydiacetylene/glycolipid liposomes.
abstract: Supramolecular assemblies of liposomes (vesicles) made of diacetylenic lipids and synthetic mannoside derivative glycolipid receptors were successfully used to mimic the molecular recognition occurring between mannose and Escherichia coli. This specific molecular recognition was translated into visible blue-to-red color transition (biochromism) of the polymerized liposomes, readily quantified by UV-visible spectroscopy. Some transition metal cations (Cd(2+), Ag(+), Cu(2+), Fe(3+), Zn(2+) and Ni(2+)) and alkali earth metal cations (Ca(2+), Mg(2+) and Ba(2+)) were introduced into the system to analyze their effects on specific biochromism. Results showed that the presence of Cd(2+), Ag(+), Ca(2+), Mg(2+) and Ba(2+) enhanced biochromism. A possible enhancement mechanism was proposed in the process of bacterial adhesion to host cells. However, Cu(2+), Fe(3+), Zn(2+) and Ni(2+) exhibited inhibitory effects that cooperated with diacetylene lipid with a carboxylic group and increased the rigidity of the liposomal outer leaflet, blocking changes in the side chain conformation and electrical structure of polydiacetylene polymer during biochromism.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Sun
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Fan
authors.forename: Yajun
authors.initials: Y
authors.lastname: Li
authors.forename: Jinghong
authors.initials: J
authors.lastname: Li
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives*; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D006017:Glycolipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008358:Mannose / Q000737:chemistry* / Q000378:metabolism; D008670:Metals / Q000737:chemistry*; D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006017:Glycolipids; D008081:Liposomes; D008670:Metals; D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; C082361:polydiacetylene; D000114:Acetylene; D008358:Mannose