title: Fluorescent Detection of Tadalafil Based on Competitive Host-Guest Interaction Using p-Sulfonated Calix[6]arene Functionalized Graphene.
abstract: A competitive fluorescence method toward tadalafil detection has been developed based on host-guest recognition by selecting rhodamine B (RhB) and p-sulfonated calix[6]arene functionalized graphene (CX6-Gra) as the "reporter pair". Upon the presence of tadalafil to the performed CX6-Gra-RhB complex, the RhB molecules are displaced by tadalafil, leading to a "switch-on" fluorescence signal. The observed fluorescence signal can be used for quantitative detection of tadalafil ranging from 1.00 to 50.00 μM with a detection limit of 0.32 μM (S/N = 3). The inclusion complex of tadalafil and CX6 was studied by molecular docking and the results indicated that a 1:1 host-guest stoichiometry had the lowest ΔG value of -7.18 kcal/mol. The docking studies demonstrated that the main forces including π-π interactions, electrostatic interactions, and hydrophobic interactions should be responsible for the formation of this inclusion compound. The mechanism of the competitive host-guest interaction was clarified. The binding constant (K) of the tadalafil/CX6 complex was more than 5 times greater than that of RhB/CX6.
authors.affiliation: School of Chemical Science and Engineering, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Long
authors.initials: L
authors.lastname: Yang
authors.affiliation: Laboratory for Conservation and Utilization of Bio-resource, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao
authors.affiliation: School of Chemical Science and Engineering, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Yucong
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Chemical Science and Engineering, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ran
authors.affiliation: School of Chemical Science and Engineering, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Guogang
authors.initials: G
authors.lastname: Deng
authors.affiliation: School of Chemical Science and Engineering, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Xie
authors.affiliation: School of Chemical Science and Engineering, Yunnan University , Kunming 650091, People's Republic of China.
authors.forename: Can-Peng
authors.initials: CP
authors.lastname: Li
keywords: calix[6]arene; competitive host−guest interaction; fluorescence; graphene; tadalafil