Chemical Engineering Journal, Vol.306, 1162-1171, 2016
Boronic acid-containing optically active microspheres: Preparation, chiral adsorption and chirally controlled release towards drug DOPA
A judicious combination of chiral structure with other functionalities in one entity may provide novel materials. For this purpose, boronic acid functional group was integrated with optically active helical substituted polyacetylene microspheres. To prepare the designed functional microspheres, two substituted acetylene monomers, i.e. chiral monomer M-1 and achiral monomer M-2 which was prepared from a boronic acid derivative, were synthesized and copolymerized through suspension polymerization for constructing polymeric microspheres. SEM images demonstrated the successful formation of the microspheres. X-ray photoelectron spectroscopy was measured to determine boronic acid content on the surface of the as-prepared microspheres. Circular dichroism spectra showed that one-handed helices were formed in the copolymer chains constructing the microspheres, which enabled the microspheres to exhibit enantio-differentiating adsorption capacity towards 3,4-dihydroxy-L-phenylalanine (L-DOPA), whereas 3,4-dihydroxy-D-phenylalanine (D-DOPA) was preferentially released. Amazing synergistic effects occurred in the helical polymer chains and the pendant boronic acid moieties. Desorption capacity and recyclability of the microspheres were also clearly verified. The unprecedented optically active microspheres hold practical applications for developing materials used for chiral adsorption, enantiomeric drug controlled release, etc. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Boronic-acid;Optical activity;Helical polymer;Chiral adsorption;Chirally controlled release