title: Disintegration of layer-by-layer assemblies composed of 2-iminobiotin-labeled poly(ethyleneimine) and avidin.
abstract: A layer-by-layer thin film composed of avidin and 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) was prepared and their sensitivity to the environmental pH and biotin was studied. The avidin/ib-PEI multilayer assemblies were stable at pH 8-12, whereas the assemblies were decomposed at pH 5-6 due to the low affinity of the protonated iminobiotin residue to avidin. The avidin/ib-PEI assemblies can be disintegrated upon addition of biotin and analogues in the solution as a result of the preferential binding of biotin or analogues to the binding site of avidin. The decomposition rate was arbitrarily controlled by changing the type of stimulant (biotin or analogues) and its concentration. The avidin/ib-PEI assemblies were disintegrated rapidly by the addition of biotin or desthiobiotin, whereas the rate of decomposition was rather slow upon addition of lipoic acid or 2-(4'-hydroxyphenylazo)benzoic acid. The present system may be useful for constructing the stimuli-sensitive devices that can release drug or other functional molecules.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Sato
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Anzai
mesh_terms: D001360:Avidin / Q000737:chemistry*; D001710:Biotin / Q000031:analogs & derivatives* / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D011094:Polyethyleneimine / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D008567:Membranes, Artificial; D001360:Avidin; D001710:Biotin; D011094:Polyethyleneimine; C028072:2-iminobiotin