Fluorescent detection of cholesterol using β-cyclodextrin functionalized graphene

Abstract

A fluorescence based cholesterol detection method has been developed using competitive host-guest interaction between graphene bound β-cyclodextrin (β-CD) with rhodamine 6G (R6G) and cholesterol. Fluorescence of β-CD incorporated R6G is quenched by graphene but is 'turned on' by cholesterol as it replaces R6G from the β-CD host.

Turn-on fluorometric β-carotene assay based on competitive host-guest interaction between rhodamine 6G and β-carotene with a graphene oxide functionalized with a β-cyclodextrin-modified polyethyleneimine

“…S5). The absorption maximum of R6G in the presence of β-CD-PEI-GO was red shifted relative to the absorption maximum of free R6G, indicating that the R6G molecules had entered the hydrophobic β-CD cavities [11,18,19]. The results showed that R6G forms a host-guest complex with β-CD and that GO acts as a fluorescence quencher.…”

“…2a. When β-CD-PEI-GO was added to the R6G solution, R6G molecules entered the β-CD cavities in the β-CD-PEI-GO because of hydrophobic interactions, and the fluorescence intensity decreased rapidly because Förster resonance energy transfer and electron transfer will have occurred because of the proximity of the R6G molecule to the GO [18,19]. Stern − Volmer plots of this phenomenon were shown in supplementary information (Fig.…”

“…Graphene oxide (GO), which is a two-dimensional nanosheet, has effective electron transfer properties that allow it to strongly quench fluorescence, and these properties have been used creatively in the construction of GO-quenched optical sensors for various analytes [15][16][17]. Several well-designed fluorescent probes based on graphene-β-CD-rhodamine 6G (R6G) composites and GO-β-CD-R6G composites have recently been developed [18,19]. In these sensors, the fluorescence of the R6G incorporated in the β-CD is quenched by the graphene or GO but is 'turn-on' by an analyte when the analyte becomes associated with the β-CD host, replacing the R6G [ 18,19].…”

“…Several well-designed fluorescent probes based on graphene-β-CD-rhodamine 6G (R6G) composites and GO-β-CD-R6G composites have recently been developed [18,19]. In these sensors, the fluorescence of the R6G incorporated in the β-CD is quenched by the graphene or GO but is 'turn-on' by an analyte when the analyte becomes associated with the β-CD host, replacing the R6G [ 18,19]. Graphene and GO have been found to be flexible lamellar materials that can adsorb cationic dyes through π-interactions or electrostatic interactions [20][21][22].…”

Controlled synthesis of Pt/CS/PW12-GNs composite as an anodic electrocatalyst for direct methanol fuel cells

“…In addition, the electrocatalytic unstability and easy poisoning by COlike intermediate species for Pt/graphene-based catalysts have limited their wider and further applications ). An attractive option is to functionalize GNs in order to obtain aqueous dispersion graphene nanosheets (AD-GNs) Mondal and Jana 2012;Yu and Dai 2010). The availability of AD-GNs not only drastically reinforces its interaction with platinum precursor, helping to control the morphology of platinum after reduction process, but also avoids irreversible aggregation of Pt/graphene composites .…”