A nano-molar sensitive fluorescence sensor for cucurbit[7]uril

Cucurbit[n]urils (CB[n], n = 5–8) are the most important class of host molecules that are widely applied in various important applications. Until now, no sensitive sensor has been developed exclusively for detecting cucurbiturils. Here, we have utilized the supramolecular assembly of acriflavine and graphene oxide (ACF-GO) as a fluorescence sensor for the detection of cucurbituril family members such as CB[5], CB[6] and CB[7] with the discrimination of fluorescence intensities. Among them, CB[7] displayed the highest sensitivity, which can be detected as low as nano-molar concentration, and that allowed us to make a facile fluorescence method of detection for CB[7] and other CBs.

Supramolecular assembly of acriflavine on the graphene oxide turn-off the fluorescence of acriflavine and upon interaction with cucurbit[7]uril, that released the acriflavine to the solution and turn-on the fluorescence, which allowed to detect the CB[7] to the lowest of nano-molar concentration.