Dual Signals Electrochemical Biosensor for Point-of-Care Testing of Amino Acids Enantiomers

A highly sensitive electrochemical sensor based on both potential and current dual signals was constructed via polypyrrole-coated chiral carbon nanotubes (L/D-CNT@PPy) loaded with Pt nanoparticles (Pt NPs) and β-cyclodextrin (β-CD) hybrid. Using L/D-CNT and β-CD as chiral selectors, PPy and Pt NPs enhanced the conductivity and the sensors showed excellent performance for chiral recognition of tyrosine (Tyr) and tryptophan (Trp). The linear ranges of the D-CNT@PPy@Pt NPs@β-CD sensor were 3–30 μM (Tyr) and 19.6–196 μM (Trp), respectively, the detection limits were 0.107 nM (Tyr) and 0.133 nM (Trp), respectively, and the recoveries for L-Tyr were 96.56 %–106.32 %. This electrochemical sensor based on a dual-signal strategy of potential and current was expected to be used in the field of point of care testing (POCT).