Diaminoterephthalate‐EDTA and ‐EGTA Conjugates – “Turn on” Fluorescence Sensors for Zinc Ions

N-doped carbon nanomaterials as fluorescent pH and metal ion sensors for imaging

Herein we describe the facile synthesis of new N-doped carbon nanoparticles (CNPs) obtained from 1,10-phenanthroline by the solvothermal method. Characterization of CNPs were carried out with transmission electron microscope (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectra (FTIR), UV-vis absorption spectra, and luminescence spectra. CNPs were pH sensitive and exploited as fluorescent chemosensors and imaging agents for Al(III) and Zn(II) ions in real-life samples. Remarkably, we show that CNPs can be used for the detection of Al(III) and Zn(II) ions in water samples. Accordingly, the results indicate that CNPs are highly effective in detecting Zn(II) content of cosmetic creams. We also demonstrated that the CNPs could be used for in vitro imaging of Al(III) and Zn(II) in Human Larynx Squamous Cell Carcinoma (Hep-2). Finally, Al(III) imaging in Angelica Officinalis root tissue was also achieved successfully. The CNPs are promising as luminescent multianalyte (pH, Al(III) and Zn(II)) sensors.

Synthesis of a Maleimide-Diaminoterephthalate Fluorescence Dye as a ‘Turn-On’ Probe for the Detection of Thiols

A fluorescence ‘turn-on’ probe for the detection of thiols was prepared in three steps. A diaminoterephthalate chromophore (λabs = 472 nm) was equipped with a maleimide moiety as reactive group. Upon conjugate addition of the thiol, the fluorescence intensity is increased by a factor of about twenty (λem = 567 nm, quantum yield Φ = 1% → 14%). The probe is used to establish a quantitative assay for glutathione.