Efficient fluorescence resonance energy transfer-based ratiometric fluorescent cellular imaging probe for Zn(2+) using a rhodamine spirolactam as a trigger

• Published in: Analytical chemistry (Washington) Vol. 82; no. 8; pp. 3108 - 3113
• Main Authors: Han, Zhi-Xiang, Zhang, Xiao-Bing, Li, Zhuo, Gong, Yi-Jun, Wu, Xiang-Yang, Jin, Zhen, He, Chun-Mei, Jian, Li-Xin, Zhang, Jing, Shen, Guo-Li, Yu, Ru-Qin
• Format: Journal Article
• Language: English
• Published: United States 15.04.2010
• Subjects: Fluorescence Resonance Energy Transfer - methods; Fluorescent Dyes - chemistry; HeLa Cells; Humans; Lactams - chemistry; Microscopy, Fluorescence; Rhodamines - chemistry; Zinc - chemistry
• ISSN: 1520-6882
• DOI: 10.1021/ac100376a

This letter described the design and synthesis of a novel fluorescein-appended rhodamine spirolactam derivative and its preliminary application as a ratiometric fluorescent cellular imaging probe for Zn(2+). The ratiometric fluorescent signal change of the probe is based on an intramolecular fluorescence resonance energy transfer (FRET) mechanism modulated by a specific metal ion induced ring-opening process of the rhodamine spirolactam (acting as a trigger). In the new developed sensing system, the emission peaks of the two fluorophores are well-resolved, which can avoid the emission spectra overlap problem generally met by spectra-shift type probes and benefits for observation of fluorescence signal change at two different emission wavelengths with high resolution. It also benefits for a large range of emission ratios, thereby a high sensitivity for Zn(2+)detection. Under optimized experimental conditions, the probe exhibits a stable response for Zn(2+) over a concentration range from 2.0 x 10(-7) to 2.0 x 10(-5) M, with a detection limit of 4.0 x 10(-8) M. Most importantly, the novel probe has well solved the problem of serious interferences from other transition metal ions generally met by previously reported typical fluorescent probes for Zn(2+) with the di(2-picolyl)amine moiety as the receptor (in this case, the fluorescence response induced by Cd(2+)is even comparable to that of Zn(2+)) and shows a reversible and fast response toward Zn(2+). All these unique features make it particularly favorable for ratiometric cellular imaging investigations. It has been preliminarily used for ratiometric imaging of Zn(2+) in living cells with satisfying resolution.