Detection of Analytes from Gas Phase Using Fluorophores and Host–Guest Complexes Incorporated into Lipid Bilayers on Silica Gel Nanoparticles

Resumo

The aim of this work was to develop chemosensors by analogy with bioreceptors based on lipid membranes stabilized on silica gel nanoparticles. Dansylglycine (DG) and a host–guest complex of DG with cucurbituril CB[8] were used as receptor fluorophores, and naphthalene and trimethylamine (TMA) in a gas phase were used as analytes. Stabilized lipid bilayers (SLBs) were obtained by the sorption of bilayer liposomes on nanoparticles under conditions that ensure the rupture of liposomes and the formation of a flat bilayer. The binding of CB[8] to SLB was performed for the first time and detected by measuring the fluorescence of the thiazole orange complex with CB[8] in a supernatant. The formation of the DG@CB[8] complex in water and a membrane manifested itself in F_DG quenching and a shift of the F_DG maximum toward short or long waves in water and in the membrane, respectively. On naphthalene excitation at 290 nm, the F_DG response was due to energy transfer from naphthalene to DG. The F_DG sharply decreased in the presence of TMA–H₂O vapors, but it increased above the initial value upon the removal of H₂O vapor. It was found that, unlike dyes embedded in a lipid matrix or sorbed on nanoparticles, the F_DG response for host–guest complexes was proportional to analyte concentration, and the F_DG wavelength did not change with analyte concentration.