Enhanced supramolecular recognition capability of gamma cyclodextrin-graphite oxide-carbon nanotube composite

[Display omitted] •The γ-cyclodextrin- thermally reduced graphite oxide-carbon nanotube composite film was successfully synthesized.•The γCD-TRGO-CNT composite shows enhanced supramolecular recognition capability compared to the γCD-GO-CNT composite.•Sensitivity of the γCD-TRGO-CNT composite dramatically increased by a factor of two compared to the γCD-GO-CNT composite. The γ-cyclodextrin–graphite oxide–carbon nanotube (γCD–GO–CNT) composite has shown the best capability and sensitivity of supramolecular recognition compared to the other two CD-GO-CNT composites (αCD-GO-CNT and βCD-GO-CNT) in our previous study. The biggest CD (γCD) was very important in the formation of the supramolecular complex and made the detection of the biomolecules easier. In this report, significantly improved supramolecular recognition capability of γCD–GO–CNT is introduced by using thermally reduced GO (TRGO), instead of typical GO. New synthesized γCD–TRGO–CNT composite film shows lower electrochemical impedance, higher carbon to oxygen atomic ratio, and larger surface area compared to the γCD–GO–CNT composite film, resulting in higher sensitivity and capability in the supramolecular recognition. The sensitivity, defined as the slope of the maximum response current versus guest molecule concentration graph, increases significantly from 4.42 to 9.44 for dopamine and from 2.21 to 4.15 for ascorbic acid. The excellent enhancement of the supramolecular recognition of the γCD–TRGO–CNT composite is attributed to TRGO. It is, therefore, concluded that it is very important to load γCD in the composite as well as to decrease the electrochemical impedance for effective electrochemical biosensors.