Molecular imprinted polypyrrole nanowires for chiral amino acid recognition

Recognition and separation of chiral molecules is of great importance in the field of biotechnology, especially on pharmaceutics. Molecular imprinted polymers (MIP) have been proved as a powerful tool for the separation of target molecules. In this paper, polypyrrole (PPy) nanowires with an average diameter of ca. 100 nm and few micrometers in length were successfully prepared by electrochemical polymerization, in which enantiomeric camphorsulfonic acid (D- or L-CSA) molecule acted as both the dopant and molecular imprinting pseudo-template. Both electrochemical impedance spectra (EIS)and circulardichroism (CD) spectra were employed to demonstrate the enantioselective interaction between de-doped PPy nanowires imprinted with CSA enantiomers (MIP-PPy) and chiral phenylalanine (D- or L-Phe). EIS leads to the characterization of interfacial electron resistance of the PPy coated electrode, while CD spectra provides spectral evidence for the enantioselective recognition event. Both methods proved that MIP-PPY nanowires have the capability for the recognition and separation of chiral phenylalanine. The sensitivity of the chiral recognition was further investigated by using various concentrations of chiral Phe and adsorption time.This approach provides a potential route for fabricating enantioselective recognition polypyrrole nanostructures that could be employed in enantiomeric sensoring or separating various chiral molecules. (c) 2008 Elsevier B.V. All rights reserved.