Host‐Guest Complexes of l ‐Borneol with Cucurbituril and Cyclodextrin and Its Potential Use in Analysis of Drugs

Host–guest inclusion of l ‐borneol with cucurbit[7]uril, cucurbit[8]uril, β‐cyclodextrin and HP‐β‐cyclodextrin in aqueous solution was investigated by Isothermal titration calorimetry and 1 H NMR spectroscopy. Furthermore, a supramolecular fluorescent probe between cucurbit[8]uril (Q[8]) and Proflavine (PF) (designated 2PF@Q[8]) showed a remarkable fluorescence enhancement to l ‐borneol. The 2PF@Q[8] fluorescent probe can be used to detect l ‐borneol with a detection limit of ∼10 −8  mol/L. A good linear relationship of emission intensity at 514 nm for l ‐borneol at concentrations of 0.1–3.0 μmol/L was observed. The proposed sensing mechanism was investigated using 1 H NMR spectroscopy and ITC. Fluorescent cell imaging of prostate cancer (PC3) cells showed the that the 2PF@Q[8] fluorescent probe could be used to image l ‐borneol in living cells.