HOST-GUEST MOLECULAR RECOGNITION INVOLVING MEMBRANE-POTENTIAL CHANGES

Studies on host-guest molecular recognition at membrane surfaces, whic h involves changes in the membrane potential, are described. A special focus was placed on basic approaches for the potentiometric discrimin ation of organic guests in liquid membrane systems. The following mode s of host-guest interaction have been exploited for the structure disc rimination based on membrane potential changes. (i) Electrostatic inte raction by protonated polyamine hosts to discriminate organic anion gu ests. (ii) Complementary base pairing by hosts having a cytosine resid ue to discriminate nucleotide guests bearing guanine and adenine bases . (iii) Inclusion of nonpolar moieties of guests by a calix[6]arene he xaester or a beta-cyclodextrin derivative to discriminate amine guests having different steric structures. Some characteristic aspects of ho st-guest molecular recognition at membrane surfaces are discussed in c omparison with those in homogeneous solutions.