A novel aggregation-induced emission fluorescent probe for nucleic acid detection and its applications in cell imaging Xiaowei Xu   , Shengyong Yan   , Yimin Zhou, Rong Huang, Yuqi Chen, Jiaqi Wang, Xiaocheng Weng, Xiang Zhou ⇑ College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Wuhan University, Hubei, Wuhan 430072, PR China article info Article history: Received 4 February 2014 Revised 19 February 2014 Accepted 25 February 2014 Available online 5 March 2014 Keywords: Fluorescent Nucleic acid Aggregation-induced emission Gel electrophoresis Cell imaging Dye abstract A new kind of aggregation-induced emission compound was synthesized and used as the probe of nucleic acid. The characterization of this compound was studied. Both the RNA and DNA were detected by using this probe. And the detection scope of DNA and RNA was different. We researched the selectivity of our probe in double and single strand DNA sequences. The visualization of gel electrophoresis and the cell nucleus imaging were researched as well. Compared with the traditional nucleus dye Hoechst 33258, our probe also has the potential to be nucleus dye. And the cell toxicity was well performed by MTT assays. Ó 2014 Elsevier Ltd. All rights reserved. It is well known that the detection of nucleic acid is very impor- tant in genetic engineering, forensics, and bioinformatics. 1–3 There- fore, many nucleic acid probes have been designed and synthesized based on the structures of nucleic acids. It has been reported that ethidium bromide (EB), Hoechst dyes, acridizinium salts, cyanine derivatives, and ruthenium complexes which based on fluorescent enhancement have been developed as nucleic acid probes. 4–15 There into, EB is cheap and widely used in molecular biology labo- ratories as a nucleic acid stain. However, EB is thought to be a strong mutagen or carcinogen. Currently, some alternatives to EB such as SYBR-based dyes are found to be less carcinogen. 14 So it is desirable to develop more fluorescent probes which could be safer for detection of nucleic acid in aqueous solution. Some fluorescent dyes can aggregate in aqueous buffer or be bound to biomacromolecules. 16–18 The fluorescent signals fade when the dyes aggregate. This aggregation-caused quenching (ACQ) effect is a major problem in the development of bioprobes and biosensors. 19–21 Herein we designed and synthesized a derivative of p-phenylenediacetonitrile for the detection of nucleic acid. And we named the compound as FcPy. FcPy has strong fluorescence emis- sion under UV light (k ex = 365 nm) (Scheme 1). This phenomenon of aggregation-induced emission (AIE) that the fluorescence enhancement attributed not only to the spatial confinement effect but also to the formation of specific supramolecular stacking archi- tecture is the opposite of ACQ effect and has been widely studied re- cently. 1–3,22 We studied the AIE characteristic of FcPy by using the traditional methods (Fig. S8). NC CN O O N N Br Br FcPy weak fluorescent strong fluorescent FcPy nucleic acid UV 365 nm Scheme 1. Schematic illustration of the fluorescence ‘Turn-On’ system for detec- tion of nucleic acid with FcPy. http://dx.doi.org/10.1016/j.bmcl.2014.02.071 0960-894X/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: xzhou@whu.edu.cn (X. Zhou).   These authors contribute equally to the works. Bioorganic & Medicinal Chemistry Letters 24 (2014) 1654–1656 Contents lists available at ScienceDirect Bioorganic & Medicinal Chemistry Letters journal homepage: www.elsevier.com/locate/bmcl