Imaging Analysis of Biological Trace Elements

Abstract

Imaging measurement methods are powerful tools to visualize the distribution and function of trace elements in living systems. A number of trace element imaging studies by radioisotopes and fluorescent probes have contributed to understand their essential roles. Recently, to investigate physiological roles of intrinsic trace elements, many efforts have been made to develop element-selective fluorescent probes such as Ca²⁺, Mg²⁺, Cu²⁺, etc. Zinc is also known to play important roles in biological processes. Although a variety of Zn²⁺-selective fluorescent probes has been developed, most of them presented so far possess a fluorescent core and a separate part for binding to Zn²⁺ within the molecule, so that the molecular weight is usually large and the molecules are hydrophobic. As a result, the applications of such molecules often face difficulties due to their low solubility in aqueous media. Thus, we developed lowmolecular-weight Zn²⁺ fluorescent probes based on a bipyridine scaffold to detect the Zn²⁺ levels in cellular systems.