A Novel Cu²⁺ Probe Based On Signaling Mechanism Of N = N Isomerization

Copper is a transition trace elements essential for most kinds of life. Copper ions as many structural and catalytic factor of kinds of proteins and enzymes in the human body, play a crucial regulatory role in metabolism, hematopoietic system and immune system. But alterations of its homeostasis will lead to serious diseases such as Wilson disease and Menkes syndrome characterized by the inability to distribute copper to cells and tissues appropriately. Besides, copper ion also has a great impact on survival of microorganisms and growth of plants. Due to the indispensable role, detection of trace copper ions in the environment and biology gains increasingly importance. However, due to the low concentration in vivo and living cells, common copper ions can’t get sensitively and effectively detection results, and therefore to design a more sensitive and effective copper ion probe is imperative. The study aims to design a new copper ion fluorescent probe based on the concept of nitrogen-nitrogen double bond reversible isomerization under irradiation resulting in fluorescence quenching, while according to generating a new covalent bond catalyzed by Cu2+ thereby suppressing the isomerization resulting in the fluorescence dramatically increase. Compared with the conventional Cu2+ fluorescent probes, the new probe advantages in lower environmental impact, lower background signal, without damage to the detected environment, and more important is that this probe has good solubility so it can be applied to intracellular detection.