Jinwei Gao

Dual-target optical sensors assembled by lanthanide complex incorporated sol–gel-derived polymeric films

AbstractnSensors bearing functional units that could transform the chemical recognition into readable signals due to binding to single or even more targets have received much attention. Here, two F−/Cu2+ optical sensors based on lanthanide edifices were designed. The f–f forbidden transitions of lanthanide elements differ significantly from organic compounds since they exhibited favorable features such as narrow emissions and high color purity. Europium(III) complex of 2-(3-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline (Eu-1) and europium(III) ternary complex of 2-(3-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline and dibenzoylmethane (Eu-2) showed on–off changes in responses to the guest species. The excitation wavelength of Eu-2 could be extended to nearly visible light range, and this longer wavelength sensitisation will be useful in the selection of cheap laser sources. Generally organic complexes suffered from the instabilities in practical uses, the encapsulation of indicators into hosts will be necessary. Therefore, the lanthanide containing hybrid films which were composed of cross-linked siloxane and polymeric matrices were also prepared. The inorganic–organic film could be excited at 410xa0nm and demonstrated improved thermal stability. Moreover, we could detect F− and Cu2+ in aqueous mixed solution and this feature would be favorable for future uses.Graphical AbstractF−/Cu2+ optical lanthanide sensors were designed. The excitation wavelength of europium(III) complex with 2-(3-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline and dibenzoylmethane (Eu-2) could be extended to nearly visible light range. Moreover, the Eu-2 doped film with cross-linked siloxane and polymeric hosts was also prepared.

Study of a water-soluble fluorescent sensor based on the Eu(III) pefloxacin complex.

The antibiotic type organic structure pefloxacin binds well with europium (III) ions as a useful scaffold for assembling optical probes and allows energy transfer from ligand to metal ions through coordination linkages. This water-soluble chemosensor demonstrated significant off-on (red) changes from an alkaline to a neutral environment (pHxa014-8). The emission changed from red to blue under acidic conditions (pHxa07-2). The whole process was completely reversible and effective within the pH range 2 to 14. Moreover, this probe system exhibited distinct luminescence quenching upon the addition of Cu2+ or Fe3+ . This general modular route will permit easy detection and the concept can be extended to a variety of quinolones for sensing purposes.

Molecular imaging of biothiols and in vitro diagnostics based on an organic chromophore bearing a terbium hybrid probe

In this research, a novel terbium-based luminescent hybrid inorganic/organic probe was designed and synthesized. Mesoporous silica nanospheres dispersed in water were used as the appropriate host for the covalently linked lanthanide-containing organic structures. The lanthanide structure was linked to a sulfonate ester unit, which, in the presence of biothiols, was cleaved to result in terbium emission. The hybrid probe exhibited the capabilities of quantitative determination and detection limits for biothiols were presented (36.8 nM for Cys, 32.5 nM for GSH, and 34.7 nM for Hcy). Evaluation of luminescence changes in cell culture demonstrated that this smart probe is cell membrane permeable and selectively lights up in the presence of cysteine and glutathione in human embryonic kidney cells and human lung adenocarcinoma cells. This variation in the presence of biothiols can be controlled by the treatment with N-methylmaleimide. The narrow line-like bands and long-lived excited states of this terbium luminescent sensor allows the discrimination of scattering signals and interfering fluorescence derived from biological tissues.

Two novel sol–gel-derived nanostructures and their hemoglobin sensing features

Sol–gel-derived nanosilica materials covalently anchored by functionalized terbium complexes with different dimensions were prepared. Zero-dimensional hybrid had a diameter of 50xa0nm with regular spherical shape. The lengths and widths of 1D nanorod hybrid were in the range of 50–70 and 20–30xa0nm. The specific surface areas of the two-dimensional materials were 81 and 108xa0cm2/g, respectively. Both materials bind hemoglobin in aqueous buffer solution (pH 7.4) as shown by striking luminescence changes. These novel findings will pave the way for the application of novel nanostructured lanthanide hybrids in sensor devices.Graphical Abstract