title: Bulky 4,6-disubstituted tetraphenylethene-naphthalimide dyad: synthesis, copolymerization, stimuli-responsive fluorescence and cellular imaging.
abstract: We report the design and synthesis of a tetraphenylethene substituted with naphthalimide at the 4, 6 positions, named NI-2TPE. NI-2TPE exhibits strong solvent-dependent emission properties with combined ICT and AIE characteristics in THF-H2O systems. This probe was used directly on test papers to distinguish normal organic solvents using their emission colours under UV light based on its AIE and ICT nature. Thanks to the vinyl group in NI-2TPE, we synthesized a copolymer of NIPAM and NI-2TPE, termed P(NIPAM-co-NI-2TPE). The resulting polymer is highly soluble and fluorescent in water (ΦF= 15.4%). Due to the well-known thermo-responsive character of NIPAM, P(NIPAM-co-NI-2TPE) exhibits an interesting fluorescence change in response to various temperatures. Due to the thermo-induced shrinking of the PNIPAM chain, the fluorescence intensity gradually increased from 20 to 34 °C. As the temperature further increased from 34 to 90 °C, the fluorescence intensity decreased sharply, which was caused by the well-known thermal effects. Furthermore, we synthesized a P(HEA-co-NI-2TPE-TPP acrylate) copolymer, in which HEA is a hydrophilic unit, TPP is a mitochondria label and NI-2TPE a fluorescent probe. The corresponding polymer probe is highly soluble in water with FLQY = 7% and we have further applied this probe as a mitochondria targeted imaging tracker in HeLa cells successfully.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei, China430074. mqzhu@hust.edu.cn leo@mail.hust.edu.cn wlgong@hust.edu.cn.
authors.forename: Qiong-Xin
authors.initials: QX
authors.lastname: Hua
authors.forename: Bo
authors.initials: B
authors.lastname: Xin
authors.forename: Jun-Xia
authors.initials: JX
authors.lastname: Liu
authors.forename: Ling-Xi
authors.initials: LX
authors.lastname: Zhao
authors.forename: Zu-Jing
authors.initials: ZJ
authors.lastname: Xiong
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Ze-Qiang
authors.initials: ZQ
authors.lastname: Chen
authors.forename: Chong
authors.initials: C
authors.lastname: Li
authors.forename: Wen-Liang
authors.initials: WL
authors.lastname: Gong
authors.forename: Zhen-Li
authors.initials: ZL
authors.lastname: Huang
authors.forename: Ming-Qiang
authors.initials: MQ
authors.lastname: Zhu
mesh_terms: D002477:Cells / Q000737:chemistry*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057054:Molecular Imaging; D015394:Molecular Structure; D053644:Naphthalimides / Q000737:chemistry*; D061848:Optical Imaging; D058105:Polymerization; D013267:Stilbenes / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D005456:Fluorescent Dyes; D053644:Naphthalimides; D013267:Stilbenes; C000617116:tetraphenylethylene