Electrochemically imprinted molecular recognition sites on multiwalled carbon-nanotubes/pencil graphite electrode surface for enantioselective detection of d- and l-aspartic acid

Molecularly imprinted polymeric nano-materials (thickness 2.03 nm) for aspartic acid enantiomers were electrochemically synthesized onto multi-walled carbon nanotubes immobilized pencil graphite electrode surface. The molecular recognition in this work was based on doping/de-doping characteristics of the conducting polymer, poly (indole-3-acetic acid), wherein the template (aspartic acid) acted as a dopant which could easily be ejected from the polymer backbone after over-oxidation. This resulted in molecular cavities complementary to the template in the imprinted polymer texture. The transduction was made via differential pulse anodic stripping voltammetric detection of d- and l-aspartic acid using respective sensors. The detection limits (S/N = 3) for d- and l-aspartic acid were found to be 0.025 and 0.016 μM, respectively in aqueous solutions. Enantioselective analysis of l-aspartic acid was validated in real samples that suggested practicability of the proposed sensor for the evaluation of this bioactive molecule as a disease biomarker in clinical settings, without any cross-reactivity and false-positives.

► Molecular recognition is based on doping/de-doping properties of conducting polymer. ► Electro-polymerized poly (indole-3-acetic acid) used as MIP-nano-material. ► Computational approach for binding affinity between monomer and template. ► Sensor assures reliable enantioselective evaluation in aqueous and real sample. ► Detection limit of proposed sensor was 0.016 μM.