Search

To prepare a fluorogenic peptide ligand which binds to an arbitrary target, we previously succeeded in seeking a fluorogenic ligand to calmodulin using in vitro selection. In this study the environment-sensitive fluorescent group in the selected peptide ligand was replaced with other fluorescent groups to find the possibility to increase the fluorogenic activity. Surface plasmon resonance measurement exhibited that the binding affinity was held even after the replacement. However, the replacement significantly affected the fluorogenic activity. It depended on the kind of incorporated fluorophors and linker length. As a result, the incorporation of 4-N,N-dimethylamino-1,8-naphthalimide enhanced the fluorescence intensity over 100-fold in the presence of target calcium-bound calmodulin. This study demonstrated that the functionality of in vitro selected peptide can be tuned with keeping the binding affinity.

In this paper, we describe a new continuous fluorescence turn-on method for trypsin assay and inhibitor screening in situ. This assay is designed based on the following assumptions: (1) It is expected that the fluorescein-labeled peptide composed of six arginine residues (Arg(6)-FAM) with positive charges will interact with the negatively charged edge of water-soluble graphene oxide (GO) because of electrostatic interactions to form a GO/Arg(6)-FAM complex. As a result, the fluorescence of fluorescein will be quenched because of the energy transfer from fluorescein to GO. (2) Arg(6)-FAM can be hydrolyzed into small fragments in the presence of trypsin, and accordingly, the GO/Arg(6)-FAM complex will be dissociated, gradually leading to fluorescence recovery for the solution. In this way, the trypsin activity can be easily assayed with the ensemble of Arg(6)-FAM and GO. Additionally, the ensemble can be employed for screening of the inhibitors of trypsin., (© 2011 American Chemical Society)

By making use of the aggregation-induced emission feature of silole, compound 1 with an ammonium group is designed and synthesized with a view to developing a new optical probe for fluorescence turn-on detection of DNA and label-free fluorescence nuclease assay. The fluorescence of 1 increases largely upon mixing with DNA, in particular for long DNA, indicating that 1 can be used for fluorescence turn-on detection of DNA. More interestingly, 1 can be employed to follow the DNA cleavage process by nuclease. Therefore, a label-free fluorescence nuclease assay method is successfully established with 1. Furthermore, this label-free fluorescence assay can also be used for inhibitor screening of nucleases. Given its simplicity, easy operation, sensitivity and cost-effectiveness, this method can be extended to other nuclease assays and high-throughput screening of nuclease inhibitors.

Molecular probes which can be modulated, functionalized and used to visualize the processes are highly desirable for understanding and manipulating biological systems. Geometric cis and trans isomers of tetraphenylethene (TPE) emerge as attractive candidates to fulfill these tasks thanks to the unique aggregation‐induced emission properties, tailorable structures, and responsiveness to external stimuli. This minireview focuses on cis and trans isomers of TPE derivatives that are functionalized with molecular recognition units for fluorescence detection, bioimaging and cancer therapy. The effects of molecular geometry on fluorescence property, target binding ability and biological activity are summarized. The feasibility to in vitro and in vivo switch molecular configuration and thus bio‐activity is discussed. Finally, the future development and challenges are discussed in view of TPE‐based stereoisomers for targeted sensing and imaging‐guided modulation of biological processes. [ABSTRACT FROM AUTHOR]

A new selective and sensitive fluorescence turn-on detection of ClO− is reported by taking advantage of the specific reaction between a 1-methyl-1,2-dihydropyridine-2-thione unit and ClO− and the aggregation induced-emission (AIE) behavior of the tetraphenylethylene unit. [ABSTRACT FROM AUTHOR]

A fast and sensitive method was established for an in-solution selection of cancer cell-targeting peptides at “single-residue resolution” by using the switchable fluorescence of tetraphenylethylene. The selected peptides have potential for biomarker tracing and can be used for targeted delivery of different cargos into living cancer cells. [ABSTRACT FROM AUTHOR]

In this Review, the configuration-dependent molecular recognition, aggregation-induced emission and bioactivities of I cis i / I trans i tetraphenylethene-based isomers are summarized. Aggregation-induced emission, fluorescence, molecular recognition, stereoisomers, tetraphenylethene Keywords: aggregation-induced emission; fluorescence; molecular recognition; stereoisomers; tetraphenylethene EN aggregation-induced emission fluorescence molecular recognition stereoisomers tetraphenylethene 1 1 1 05/30/23 20230526 NES 230526 Tetraphenylethene derivatives with adjustable molecular geometry emerge as an attractive paradigm for the development of smart and versatile chemical probes. [Extracted from the article]

The fluorescence detection of nitroreductase (NTR) and evaluation of the hypoxia status of tumor cells are vital, not only for clinical diagnoses and therapy, but also for biomedical research. Herein, we report the synthesis and application of a new fluorometric 'turn-on' probe for the detection of NTR ( TPE−NO2) that takes advantage of the aggregation-induced emission of tetraphenylethylene. TPE−NO2 can detect NTR at concentrations as low as 5 ng mL−1 in aqueous solution. The detection mechanism relied on the aggregation and deaggregation of tetraphenylethylene molecules. Moreover, this fluorescent probe can be used to monitor the hypoxia status of tumor cells through the detection of endogenous NTR. [ABSTRACT FROM AUTHOR]

We report the design and synthesis of a red fluorescent AIE light-up probe for selective recognition, naked-eye detection, and image-guided photodynamic killing of Gram-positive bacteria, including vancomycin-resistant Enterococcus strains. [ABSTRACT FROM AUTHOR]

A new sensitive fluorescence turn-on detection of gamma-radiation is reported by taking advantage of aggregation induced-emission (AIE) behaviour of the tetraphenylethylene unit and the cascade radiochemical and protonation reactions. [ABSTRACT FROM AUTHOR]

We report a method for the rapid and efficient identification of bacteria making use of five probes having fluorescent characteristics (F-array) and subsequent statistical analysis. Eight kinds of bacteria, including normal and multidrug-resistant bacteria, are differentiated successfully. Our easy-to-perform and time-saving method consists of mixing bacteria and probes, recording fluorescent intensity data by automated flow cytometry, and statistical analysis. No washing steps are required in order to identify the different bacteria simultaneously. [ABSTRACT FROM AUTHOR]

A new gelator 1 based on tetraphenylethylene (TPE) and diphenylalanine was designed and synthesized. Compound 1 was non-emissive in solution, but its fluorescence turned on after the formation of gels, due to the aggregation-induced emission (AIE) feature of TPE. Interestingly, the fluorescence was reversibly switched 'on-off' upon the 'gel-sol' transition. Scanning electron microscope (SEM), confocal laser scanning microscope (CLSM) and X-ray diffraction (XRD) were employed to study the gels. [ABSTRACT FROM AUTHOR]

Abstract: Two new organic gelators 1 and 2 based on the silole (silacyclopentadiene) framework were designed with the end to develop switchable fluorescent organogels, by making use of the aggregation-induced emission (AIE) feature of silole derivatives. As for other silole derivatives, compounds 1 and 2 exhibited AIE behavior as indicated by the significant fluorescence enhancement by introducing water to the THF solutions. Compounds 1 and 2 can gel hexane, methylcyclohexane and heptane. Large fluorescence enhancement was observed for compounds 1 and 2 after gelation. Moreover, their fluorescence intensities can be changed reversibly accompanying the gel–solution transition through alternating cooling and heating. Therefore, thermally-driven fluorescence switches can be achieved with organogels based on 1 and 2. [Copyright &y& Elsevier]

Abstract: By combining the features of photochromic spiropyran and the host–guest inclusion complex between the adamantyl (AD) and β-cyclodextrin (β-CD) derivatives, we report a temperature-gated molecular fluorescence switch. [Copyright &y& Elsevier]

Abstract: DMABN (4-N,N-dimethylaminobenzonitrile) derivatives 1 and 2 were designed as new ratiometric fluorescent sensors for saccharides and fluoride ion (F−), respectively, based on the TICT (twisted intramolecular charge transfer) mechanism. [Copyright &y& Elsevier]

Abstract: Strong pyrene excimer emission was observed for a new pyrene–thymine dyad that can be easily synthesized in the presence of Hg2+ ion. But, the enhancement of pyrene excimer emission was not detected in the presence of other metal ions. As a result, this new pyrene–thymine dyad is suited for use as a sensitive and selective “turn on” fluorescent chemosensor for Hg(II) ion. [Copyright &y& Elsevier]

Abstract: The fluorescence of a pyrene-arylmaleimide dyad and its Diels–Alder adduct can be thermally modulated through reversible Diels–Alder reaction of arylmaleimide unit with furan. Moreover, the fluorescence intensities of the Diels–Alder adduct of dyad 1 with furan vary linearly with the temperatures of the corresponding solutions, demonstrating that these molecules are interesting compounds for studies of fluorescent molecular thermometers. [Copyright &y& Elsevier]

Abstract: We design a new saccharides sensor based on the ensemble of compound 2 with a boronic group and compound 3 with two phenolic –OH groups, taking advantage of the fluorescence quenching ability of nitronyl nitroxides and reversible boronate formation between boronic acid and diol. The results show that the fluorescence of compound 2 was largely quenched upon addition of compound 3 due to the formation of the intermediate nitronyl nitroxide–anthracene dyad 1. Sequential addition of saccharides such as fructose to the ensemble of compounds 2 and 3 together with dyad 1 induced the fluorescence enhancement. These results clearly demonstrate the possibility to employ the ensemble of compounds 2 and 3 (with dyad 1) to sense saccharides. [Copyright &y& Elsevier]

Abstract: Reversible modulation of the monomer/excimer emission was observed for bispyrene molecules 1 and 2 through the solution–gel phase transition (with gelator 3 as the LMWG) and accordingly a thermo-driven molecular fluorescence switch can be established. [Copyright &y& Elsevier]

Abstract: A new selective fluorescence turn-on detection of hydrogen peroxide was established by taking advantage of the aggregation induced-emission (AIE) behavior of tetraphenylethylene unit and the reaction of hydrogen peroxide toward the arylboronic ester group in compound 1. Moreover, compound 1 was successfully utilized for the selective detection of d-glucose in aqueous solution. [Copyright &y& Elsevier]

Abstract: Hybrid hollow nanospheres of chitosan-ZnO (CS-ZnO Nps) were successfully prepared by the in situ growing of ZnO quantum dots (QDs) in an aqueous solution consisting of a cationic polymer CS and an anionic monomer acrylic acid (AA), followed by the polymerization of AA and selectively crosslinking of CS with glutaraldehyde. The as-prepared nanospheres were characterized by transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–visible spectrometer (UV) and fluorescence spectrophotometer (PL). ZnO QDs were dispersed evenly in the shell of hybrid nanospheres, with its dimension less than 5nm. These fluorescent CS-ZnO Nps were expected to be simultaneously used as biological fluorescent labeling and a carrier for guest materials. [Copyright &y& Elsevier]

Abstract: Triad 1 consisting of TTF, maleimide and pyrene units acts as a temperature-regulated molecular redox fluorescence switch by combining features of the three moieties. Our results show that the fluorescence modulation by redox reaction of TTF unit in triad 1 is controlled by the ‘status’ of the maleimide unit which is involved in the reversible temperature-dependent Diels–Alder reaction with furan. Thus, a resettable temperature-regulated molecular redox fluorescence switch is successfully realized with triad 1. [Copyright &y& Elsevier]