Authors Müller, M. ; Ouyang, W. ; Appelhans, D. ; Voit, B.
Title Enantiospecific binding at chiral polyelectrolyte multilayers
Date 16.09.2008
Abstract Two chiral polyelectrolyte multilayers (PEM) composed of poly(L-lysine) (PLL) and poly(vinylsulfate) (PVS) as well as poly(ethyleneimine-maltose) (PEI-m) and poly(vinylsulfate) and a nonchiral PEM composed of poly(ethyleneimine) (PEI) and poly(vinylsulfate) were deposited on silicon substrates using the layer by layer method. Enantiospecific interaction between PEM and chiral probes was studied using enantiomers of either L-/D-glutamic acid (L-/D-GLU) or L-/D-ascorbic acid (L-/D-ASC), respectively. Both deposition and enantiospecific interaction were studied by attenuated total reflection Fourier transform (ATR-FTIR) spectroscopy and atomic force microscopy (AFM). Significant enantiospecific preference of D-GLU over L-GLU at PEM of PLL/PVS and of D-ASC over L-ASC at PEM of PEI-m/PVS and no such preference for nonchiral PEM of PEI/PVS was found . <br />The enantiospecifity of chiral PEM was further studied under variation of chiral probe concentration, pH and ionic strength as well as PEM nanostructure and orientation. Unexpectedly, long range attractive electrostatic rather than short range weak interaction forces between chiral PEM and the respective enantiomers were found to be crucial for enantiospecifity . <br />Permeation studies at membrane sheets, which were modified by PEM of PLL/Poly(styrenesulfonate) (PSS), resulted in significantly higher fluxes for L- in comparison to D-amino acids as evidenced by UV detection of depletion [2]. Hence chiral polyelectrolyte modified membranes offer potential for preparative enantiomer separation.
Journal Polymeric Materials: Science and Engineering 99 (2008) 107-108

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