One‐Step Covalent Immobilization of β‐Cyclodextrin on sp² Carbon Surfaces for Selective Trace Amount Probing of Guests

Abstract

The modification of solid surfaces with supramolecular hosts is a powerful method to tailor interfacial properties and confer chemical selectivity, but often involves multistep protocols that hinder facile upscaling. Here, the one-step covalent modification of highly oriented pyrolytic graphite (HOPG) with a β-cyclodextrin (β-CD) derivative, which efficiently forms inclusion complexes with hydrophobic guests of suitable size, is demonstrated. The grafted β-CD-HOPG surface is investigated toward electrochemical detection of ferrocene and dopamine. The enrichment of the analytes at the electrode surface, through inclusion in β-CD, leads to an enhanced electrochemical response and an improved detection limit. Furthermore, the modified β-CD-HOPG electrode discriminates analytes that form host-guest complexes with β-CD against a 100-fold higher background of electroactive substances that do not. Atomic force microscopy, scanning tunneling microscopy, and Raman spectroscopy confirm the covalent nature of the modification and reveal high stability toward solvent rinsing, ultrasonication, and temperatures up to 140 °C. The one-step covalent modification therefore holds substantial promise for the routine production of inexpensive, yet robust and highly performant electrochemical sensors. Beyond electrochemical sensor development, our strategy is valuable to prepare materials where accurate spatial positioning of functional units and efficient current collection are crucial, e.g. in photoelectrodes or electrocatalysts.

Graphene Biosensors—A Molecular Approach

“…The electrochemical behavior of the developed modified surface was tested by cyclic voltammetry towards ferrocene, hexycyanoferrate, and the neurotransmitter dopamine (DA), and it was used as a sensor for the detection of these substances. The sensor exhibited excellent sensitivity for DA detection at the nanomolar level, higher than the results reported at the time for a 3D nitrogen-doped graphene/β-CD electrode and comparable to the highest sensitivity reported for any electrochemical dopamine sensor [ 28 ].…”

Surface Functionalization of a γ‐Graphyne‐like Carbon Material via Click Chemistry

“…In comparison, the covalent bond can certainly provide a stronger interlinkage between modifiers and host materials, reinforcing the stability of the bounded molecules and further broadening their applications, particularly under harsh operating conditions [18] . Nevertheless, surface functionalization of the aforementioned carbonaceous materials via the covalent interaction is synthetically challenging due to the inert nature of benzene rings and lack of reactive ligands on the surface; introducing additional specific functional groups, such as −NH 2 , −CN and −COOH, is then required, as shown in Scheme 1a and 1b [19–21] . Therefore, seeking a new carbon material with intrinsic reactive groups to establish a strong covalent interaction with surface modifiers is desired but remains largely elusive.…”

“…[18] Nevertheless, surface functionalization of the aforementioned carbonaceous materials via the covalent interaction is synthetically challenging due to the inert nature of benzene rings and lack of reactive ligands on the surface; introducing additional specific functional groups, such as À NH 2 , À CN and À COOH, is then required, as shown in Scheme 1a and 1b. [19][20][21] Therefore, seeking a new carbon material with intrinsic reactive groups to establish a strong covalent interaction with surface modifiers is desired but remains largely elusive.…”

β-Cyclodextrin-Polyacrylamide Hydrogel for Removal of Organic Micropollutants from Water

“…β-Cyclodextrin (β-CD), which is a cyclic oligosaccharide consisting of α-1,4-linked 7 D(+)-glucose units, has been extensively studied for its ability to form supramolecular inclusion complexes with a variety of molecules that could fit into the hydrophobic cavity of β-CD [14][15][16][17][18][19][20][21]. Due to this unique property, there have been increasing interests and investigations to analyze the complexations between β-CD and various organic pollutant molecules, including BPA, PR•HCl and 2-NO [22][23][24][25].…”