An electrochemical chiral sensor for amino acids based on cyclodextrin modified thiophene-based copolymer

Abstract

Two series of thiophene-based copolymers with cyclodextrins (CDs) grafted on side chain (OH-β-CD-P3HT and Ph-β-CD-P3HT) were synthesized via click reaction, in which the pendant CDs and the polythiophenes (PTs) main chain afford stereo-selective interactions and high conductivity respectively. The copolymers have been employed to construct an electrochemical sensor to achieve efficient enantio-recognition for amino acids. The OH-β-CD-P3HT and Ph-β-CD-P3HT shows reverse interaction preference for D- and L-isomer due to the different interaction mode of native and substituted CDs with chiral guest. It is found that, higher content of block with CD in the copolymer favors lower LOD because of the specific inclusion abilities of CD, while lower content of block with CD is beneficial to chiral selectivity related to the higher structural flexibility of the polymer. The electrochemical sensor was also proven to be capable of determining the relative content of L- or D-isomer in an enantiomer pair.