Fluorescent probe for Fe(III) with high selectivity and its application in living cells

An easily available novel fluorescent probe has been synthesized by reacting rhodamine hydrazide and 2-(thiophen-2-yl)acetyl chloride. Upon mixed with Fe3+ in aqueous solution, the dramatic enhancement of fluorescence intensity as well as the color change of the solution were observed. Significantly, the probe displayed highly selective and sensitive recognition ability toward Fe3+ with a limit of detection (LOD) down to 10(-73) M. The Job's plot indicated the formation of 1:1 complex between the probe and Fe3+, and the complexation stability constant can be calculated as 2.95 x 10(4) M-1. The presence of common coexisting alkali, alkaline earth, and transition metal ions showed small or no interference to the detection of Fe3+. All these unique features make it particularly favorable for cellular Fe3+ imaging applications. The confocal fluorescent images demonstrated that the probe was cell-permeable and could be used for highly sensitive monitoring of Fe3+ levels in living cells with satisfying resolution. (c) 2017 Elsevier B.V. All rights reserved.