pH-SENSITIVE CAPSULE MEMBRANES. REVERSIBLE PERMEABILITY CONTROL FROM THE DISSOCIATIVE BILAYER-COATED CAPSULE MEMBRANE BY AN AMBIENT pH CHANGE.

Article abstract of DOI:10.1021/ja00338a010

Nylon ultrathin capsules coated with synthetic bilayers having dissociative head groups (2C//1//2PO//4** minus , 2C//1//2-cys-2COO** minus , 2C//1//2-scu-COO** minus , and 2C//1//6-gly-NH//3** plus ) were prepared. Permeations through the membrane of a fluorescent probe trapped in the inner aqueous phase could be reduced by factors of 50-100 relative to that of the uncoated capsule and reversibly controlled by pH changes of the outer medium: in the case of the capsule coated with bilayers containing phosphate (2C//1//2PO//4** minus ) and carboxylate head groups (2C//1//2-cys-2COO** minus and 2C//1//2-suc-COO** minus ), the permeation was redused in the neutral medium, increased in the acidic medium, and reverted to the original slow rate in the neutral medium, depending on the dissociation of head groups of coating bilayers.