An electrochemical and computational study for discrimination ofd- andl-cystine by reduced graphene oxide/β-cyclodextrin

Abstract

Here, we report a novel enantioselective electrochemical biosensor for the discrimination of cystine enantiomers (d- and l-cystine) using a chiral interface for the specific recognition of d- and l-cystine. The biosensor is based on reduced graphene oxide modified by β-cyclodextrin (rGO/β-CD) at the GCE surface. During the preparation of rGO/β-CD/GCE, the modified electrode surfaces were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The electrochemical behaviours of the d- and l-cystine were investigated using the rGO/β-CD/GCE by CV and compared to bare GCE. A clear separation between the oxidation peak potentials of d- and l-cystine was observed at 1.32 and 1.42 V, respectively. The electrochemical discrimination performance of the fabricated chiral sensor was also examined by differential pulse voltammetry (DPV) in a mixed solution of d- and l-cystine. In addition, the DPV technique was used for the determination of d- and l-cystine at low concentration values in the range of 1.0-10.0 μM. To investigate the amperometric response of rGO/β-CD/GCE towards d- and l-cystine, the chronoamperometry technique was used in the concentration range of 10.0-100.0 μM. The interactions of the enantiomers with rGO/β-CD were modelled by molecular docking using AutoDock Vina, and the interaction energies were predicted to be -4.8 and -5.3 kcal mol(-1) for d- and l-cystine, respectively. The corresponding values of binding constants were calculated to be 3.32 × 10(3) and 7.71 × 10(3) M(-1), respectively. The experimental and molecular docking results indicate that the rGO/β-CD/GCE has a different affinity for each enantiomer.

Optically Active Hybrid Materials Constructed from Helically Substituted Polyacetylenes

“…Nevertheless, few studies have been devoted to this newly emerging research topic with small chiral organic molecules. [32] Compared with small chiral molecules, chiral helical polymers may be more desirable for use to chirally functionalize graphene due to the well-known "chiral amplification" effect frequently occurring in helical polymers. [33] In our first study along this research direction, we used p-p interactions as the primary driving force to fabricate chiralized graphene.…”

A rapid electrochemical monitoring platform for sensitive determination of thiamethoxam based on β–cyclodextrin‐graphene composite

“…The metals improved detection sensitivity, but they are not environmentally friendly. To integrate the excellent properties of b-cyclodextrin and reduced graphene oxide, b-cyclodextrin-reduced graphene oxide was applied to modify electrodes and has been used to determine levels of chlorophenol [13], 4-nitrophenol [14], imidacloprid [15], dinotefuran [16], and other substances [17][18][19][20]. b-cyclodextrin, which has a hydrophilic exterior and a hydrophobic inner cavity, is able to form stable host-guest inclusion complexes; accordingly, it has high supramolecular recognition and enrichment capability.…”

“…b-cyclodextrin, which has a hydrophilic exterior and a hydrophobic inner cavity, is able to form stable host-guest inclusion complexes; accordingly, it has high supramolecular recognition and enrichment capability. To integrate the excellent properties of b-cyclodextrin and reduced graphene oxide, b-cyclodextrin-reduced graphene oxide was applied to modify electrodes and has been used to determine levels of chlorophenol [13], 4-nitrophenol [14], imidacloprid [15], dinotefuran [16], and other substances [17][18][19][20].…”

Analysis of affinities between specific biological ligands using atomic force microscopy

“…Fundamental knowledge of molecular interactions binding affinity and strength 7 was gained mostly by studying their in situ characteristics using techniques relying on optical 8 and magnetic tweezers 9 , or impedance spectroscopy 10 . For instance, Sischka et al, studied the dynamic translocation of ligand-complexed DNA through solid-state nanopores using optical tweezers 11 ,Liebesny et al, determined the number of proteins bound non-specifically to DNA using magnetic tweezers 12 , while Duan et al, showed how impedance spectroscopy could be used to study the formation of a silicon nanowire field-effect transistor capable to measure protein-ligand binding affinities and kinetics with sensitivities down to femtomolar concentrations 13 .…”