Graphene-based hybrid for enantioselective sensing applications

Abstract

Chirality is a major field of research of chemical biology and is essential in pharmacology. Accordingly, approaches for distinguishing between different chiral forms of a compound are of great interest. We report on an efficient and generic enantioselective sensor that is achieved by coupling reduced graphene oxide with γ-cyclodextrin (rGO/γ-CD). The enantioselective sensing capability of the resulting structure was operated in both electrical and optical mode for of tryptophan enantiomers (D-/L-Trp). In this sense, voltammetric and photoluminescence measurements were conducted and the experimental results were compared to molecular docking method. We gain insight into the occurring recognition mechanism with selectivity toward D- and L-Trp as shown in voltammetric, photoluminescence and molecular docking responses. As an enantioselective solid phase on an electrochemical transducer, thanks to the different dimensional interaction of enantiomers with hybrid material, a discrepancy occurs in the Gibbs free energy leading to a difference in oxidation peak potential as observed in electrochemical measurements. The optical sensing principle is based on the energy transfer phenomenon that occurs between photoexcited D-/L-Trp enantiomers and rGO/γ-CD giving rise to an enantioselective photoluminescence quenching due to the tendency of chiral enantiomers to form complexes with γ-CD in different molecular orientations as demonstrated by molecular docking studies. The approach, which is the first demonstration of applicability of molecular docking to show both enantioselective electrochemical and photoluminescence quenching capabilities of a graphene-related hybrid material, is truly new and may have broad interest in combination of experimental and computational methods for enantiosensing of chiral molecules.

Chiral magnetic-nanobiofluids for rapid electrochemical screening of enantiomers at a magneto nanocomposite graphene-paste electrode

“…CDs present a relatively low cost and an excellent capability to host effectively, selectivity and enantioselectivity various bioactive compounds into their hydrophobic cavities to form stable host-guest inclusion complexes (Zaidi 2017), (Saavedra et al 2008), (Muñoz et al 2016b). Although modified graphene-based platforms with CDs have also been employed in few instances for the electrochemical discrimination of TRP enantiomers, such unification of enantioselectivity with electrical conductivity has been mainly based on casting graphene-based hybrid-nanomaterials containing the CD in the form of films onto pure carbon electrode surfaces (Zor et al 2017), (Xiao et al 2017), (Ou et al 2015). This approach usually leads to a fragile modification which can result in possible diffusion problems.…”

Chiral Graphene Hybrid Materials: Structures, Properties, and Chiral Applications

“…This distinctive property also makes cyclodextrins appealing for chiral applications. Up to date, α ‐CD, [ 83 ] β ‐CD, [ 84–86,97,98,100,101,105–107 ] and γ ‐CD [ 108 ] have been intensively employed for chiral functionalization of graphene and its derivatives. Among the three types of cyclodextrins, β ‐CD shows the most extensive applicability as its cavity is well matched with common small chiral molecules.…”

Reliable chiral recognition with an optoelectronic nose

“…In this article, we investigate the enantioselectivity of this new technology with a commercial version of the eNose described by Brenet and coworkers [6]. Formally, we expect that the discrimination between two mirror molecules, or enantiomers, is possible, thanks to the potential enantioselectivity of peptides used in the device [28]. Indeed, peptides are chiral in essence and previous works with specific sensors already reported their enantioselectivity [16].…”