Self-assembly of cucurbit[7]uril on the surface of graphene/gold modified electrode

Abstract

Using supramolecular recognition capability of cucurbit[7]uril to create a novel electrochemical sensing platform was accomplished by self-assembly of cucurbit[7]uril on the surface of graphene-gold composites modified glassy carbon electrode. The graphene-gold composites consisted of electrochemically reduced graphene oxide-nafion matrix and anchored electrodeposited gold nanoparticles and the graphene-gold composites modified glassy carbon electrode (labelled as graphene-gold) were characterized by scanning electron microscopy and Raman spectrometer. Self-assembly of cucurbit[7]uril was achieved by immersing the graphene-gold electrode into cucurbit[7]uril solution and confirmed by Fourier transform infrared spectra, cyclic voltammetry and electrochemical impedance spectroscopy. Ferrocene and its derivatives served as the substrates, and the electrochemical responses of fabricated graphene-gold/cucurbit[7]uril electrode were evaluated. The results showed that the presence of cucurbit[7]uril increased the peak current, improved the reversibility of reaction and extended the recognition ability of the modified electrode.

Development of chemically modified electrode using cucurbit(6)uril to detect ranitidine hydrochloride in pharmaceutical formulation by voltammetry

“…Their general inclusion properties are high affinity and highly selective, constrictive binding interactions with lots of specific guest species, driven by a combination of ion-dipole interactions, hydrogen bonds and hydrophobic effect. 21 It is possible to immobilize cucurbiturils over electrodes. CB (n) act as chemical mediators, giving rise to a promising class of chemically modified electrodes (CMEs).…”

“…Cucurbit(n)urils or CB(n)s are cyclic organic capsules with a pumpkin like shape. 21 They bear a central hydrophobic cavity delimited by n (5-8, 10-12) carbonyl groups oriented outward forming electron rich portals on both side of the cavity which confers them their host-guest properties. Additionally, they are symmetric, thermally stable, chemically inert and poorly soluble in water, which little variation among the homologues.…”

Capture and Detection of Fentanyl with Thiolated Cucurbit[7]uril Macrocycles on Silver Nanoparticles

“…Unfortunately, due to the extremely high potency of this drug, the binding affinity of CB[7] is still below the threshold needed to enable sequestration for fentanyl detoxification at lethal drug concentrations occurring in blood, although nascent macrocycles have been reported in recent years that could achieve such affinity . Toward the creation of sensors, CB­[ n ] species can be adsorbed to metal surfaces, affording synthetic receptors that sequester small molecule guests of interest near the metal surface; this feature is of particular relevance for surface-specific techniques like surface-enhanced Raman spectroscopy (SERS) using metal nanoparticle sensors. − By predictably and selectively sequestering guest molecules near a nanoparticle surface, this approach to detector design has the possibility of significantly enhancing the detection limits of otherwise elusive analytes in complicated matrices. In this work, the selective binding of fentanyl-type drugs to CB[7] is explored via competitive NMR studies on drug mixtures, followed by an assessment of the sensing application of a novel thiolated CB[7] macrocycle for anchoring to a silver nanoparticle (AgNPs) substrate for fentanyl detection using SERS (Scheme ).…”

Brilliant Green Decorated Graphene Oxide for the Detection of Cucurbit[7]uril

“…So, we decided to change the fluorescent dye that we used to decorate the graphene oxide by the non-fluorescent dye to explore the same hypothesis, which would require only visible spectrophotometer and such instruments are the most inexpensive one. Among the various dyes existing, we have selected brilliant green (BG), because it is an inexpensive dye with high intensive color, even at the lowest concentration [21]. Brilliant green is expected to get absorbed on graphene oxide by the non-covalent interactions through the π-π interactions of the aromatic groups of dye with the graphene oxide [22,23].…”