Synthesis, Characterization and Theoretical Calculations of a New Fluorescent Probe for Detection Cu2+

A Terbium Ion-Based Dual-Ligand Fluorescent Probe for Highly Selective and Sensitive Detection of Cu2+ Ions

In this study, a fluorescent probe (GMP-Tb-SSA) utilizing lanthanide coordination polymer nanoparticles, GMP-Tb, as a sensing platform, and 5-sulfosalicylic acid (SSA) as a cofactor ligand was proposed for the detection of copper ions (Cu2+). GMP-Tb was synthesized by the self-assembly of guanine monophosphate (GMP) and terbium ion (Tb3+), and SSA was introduced as a sensitizer into the GMP-Tb network. Cu2+ could efficiently inhibit the electron transfer from the ligand GMP to the central ion, Tb3+, leading to a significant quench of fluorescence of Tb3+. The method is highly selective with a linear range of 0 to 21 µM and a detection limit of 300 nM. It is not interfered by metal ions, amino acids, and other species, and can be successfully applied to the detection of Cu2+ in real water samples.

Neuroprotective Activity of a Novel Synthetic Rhodamine-Based Hydrazone against Cu2+-Induced Alzheimer's Disease in Drosophila

A new rhodamine-based probe 3,5-di-tert-butylsalicylaldehyde rhodamine hydrazone (RHTB) has been synthesized and well characterized using spectroscopic techniques and single-crystal X-ray crystallography. Among several metal ions, it selectively detects Cu²⁺ ions as monitored by UV-Vis and emission spectral titrations. It displays "turn on" behavior owing to the opening of a spirolactum ring and the presence of 3,5-di-tert-butyl as an electron releasing group. Further, Cu²⁺ ions play a pivotal role in extracellular aggregation of Aβ₄₂ peptides. So far, we know probably that there are no promising drugs available in this regard. Hence, countering the Cu²⁺ ions by RHTB chelation against orally administered Cu²⁺ ion-induced neurotoxicity in the eye tissue of Drosophila expressing human Aβ₄₂ (amyloid-β₄₂) has been tested. The present study involves in vivo and in silico approaches. They reveal the therapeutic potential of RHTB against Cu²⁺ ion-induced Aβ₄₂ toxicity in Alzheimer's disease (AD) model of Drosophila.