The fabrication of carbon nanotubes array-based electrochemical chiral sensor by electrosynthesis

How to align the single-walled carbon nanotubes (SWCNTs) onto the electrode vertically and to control their density and orientation are still a major challenge. Theoretically, properly selected chiral SWCNTs can discriminate enantiomers through their different dielectric response to the adsorption of chiral species, few reports can confirm this theoretic model. Herein, we presented a new strategy to fabricate SWCNTs array-based electrochemical chiral sensor. Carboxylated chiral SWCNTs were vertically attached to the oxidized glass carbon electrode with ethylenediamine as a linker by electrosynthesis. The electrode surface was characterized with atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). The practicability of the sensor was validated by chirally recognizing 3,4-dihydroxyphenylalanine as a model molecule. We found that both the highly ordered standing of SWCNTs and the application of square wave voltammetry (SWV) amplified the intrinsic chirality of chiral SWCNTs.