唐本忠    

National Science Review

2017

Aggregation-induced emission luminogens (AIEgens) have attracted extensive interest for their outstanding luminescence properties in the aggregated state and even in the solid state. In this work, we developed a series of novel AIEgens based on 2,5-bis(4-alkoxycarbonylphenyl)-1,4-diaryl-1,4-dihydropyrrolo[3,2-b]pyrrole (AAPP). The AIEgens can be facilely synthesized through a single-step reaction under mild conditions with satisfactory yields. Interestingly, AAPP was found to have multiple luminous mechanisms that result in variable fluorescence properties. The propeller-like structure of AAPP enables a restricted intramolecular rotation (RIR) process which significantly enhances its fluorescence in the aggregated state (i.e. AIE fluorescence). In addition, there is a donor-acceptor interaction between the heterocycle center and the alkoxycarbonyl units in AAPP which allows a typical twisted intramolecular charge transfer (TICT) process in the dispersed state, resulting in strong fluorescence emissions in non-polar or low-polarity solvents but fluorescence quenching in high-polarity solvents. Due to the tunable RIR and TICT processes and the multiple fluorescence, AAPP compounds exhibit multifunctional applications: (1) as a reversible fluorescent thermometer, AAPP exhibited excellent fatigue resistance. There was a good linear relationship between its fluorescence intensity and temperature from 10 °C to 60 °C. (2) The desethyl AAPP derivative (CAPP) was successfully applied in the detection of Cd(ii) in aqueous solution at neutral pH, and showed a 500-fold fluorescence "turn-on" response to Cd(ii) with good selectivity.

李恺    Liu Yuanyuan    Li Yuanyuan    Feng Qi    侯红卫    唐本忠    

Chemical Science

2017

Tetraphenylethylene (TPE) and its derivatives are the typical aggregation-induced emission (AIE) compounds with helical chirality, and they have enormous applications potential in chiral sensor, asymmetric catalyst, optoelectronic materials, and so on. The aggregation-induced helical chirality of TPE and its derivatives can only be observed in condensed phase such as crystalline or film state. The accurate determination of absolute configuration (AC) of TPE core compounds is complicated and difficult, especially when there is no heavy atoms exist in their structures. Herein, we demonstrate a powerful and convenient method to quickly determine the helical chirality of these stereochemically labile TPE core compounds through the combination of comprehensive solid-state chiroptical spectroscopy and theoretical calculation. Our study reveals that from lower to higher energy of the fingerprint region, the first electronic circular dichroism (ECD) band in the 300-450 nm or the first most intensive vibrational circular dichroism (VCD) peak in the 875-730 cm can be used as the diagnostic bands for the AC determination of the TPE core with the fixed chirality. If these diagnostic bands cannot be observed in ECD or VCD spectra, the helical chirality of the atropisomers of TPE derivatives is not fixed. The explicit AC determination of TPE core contributes to the study of the helical chirality of supramolecular TPE core derivatives and allows for the further fabrication of novel chiral AIE functional materials. (Graph Presented).

Li Dan    胡蓉蓉    Guo Dong    Zang Qiguang    Jianhui Li    Wang Yue-Kui    Yansong Zheng    唐本忠     Zhang Hui   

Journal of Physical Chemistry C

2017

We report the synthesis and properties of a cationic hyperbranched polymer containing tetraphenylethene (TPE) and pyridinium moieties. The polymerization was efficient under mild conditions (60 °C, 12 h) and the yield was as high as 92%. Due to the existence of the TPE moieties, the polymer exhibits an evident aggregation-enhanced emission (AEE) property, and the fluorescence quantum yield is 13.5% and 6.5% as a solid and in a dilute solution, respectively. The conjugation of TPE with the pyridinium moieties bestows the hyperbranched polymer with an extremely large Stokes shift of over 200 nm, and low susceptibility to external stimuli such as mechanical grinding in solid, solvent polarity in solution, and pH change in aqueous medium. The cationic characteristic gives the red-emitting polymer good membrane permeability, and the results of living cell stain experiments suggest that it may find applications as a stable fluorescent probe for bioimaging.

Chen Rui    Gao Xiaoying    Xiao Cheng    Anjun Qin    Jingzhi Sun    唐本忠    

Polymer Chemistry

2017

Fluorescent sensors with advantages of excellent sensitivity, rapid response, and easy operation are emerging as powerful tools in environmental monitoring, biological research, and disease diagnosis. However, conventional fluorophores featured with π-planar structures usually suffer from serious self-quenching in the aggregated state, poor photostability, and small Stokes' shift. In contrast to conventional aggregation-caused quenching (ACQ) fluorophores, the newly emerged aggregation-induced emission fluorogens (AIEgens) are featured with high emission efficiency in the aggregated state, which provide unique opportunities for various sensing applications with advantages of high signal-to-noise ratio, strong photostability, and large Stokes' shift. In this review, we will first briefly give an introduction of the AIE concept and the turn-on sensing principles. Then, we will discuss the recent examples of AIE sensors according to types of analytes. Finally, we will give a perspective on the future developments of AIE sensors. We hope this review will inspire more endeavors to devote to this emerging world.

Meng Gao    唐本忠    

ACS Sensors

2017

The glass transition temperature (T) is an important physical parameter and signifies the reversible transition process between the glassy state and the rubbery state in polymeric materials. Herein, a simple yet reliable method, denoted as ADEtect, utilizing aggregation-induced emission luminogens (AIEgens) for T measurement was developed. The fluorescent images of AIEgen-doped polymer films taken at different temperatures were monitored by a camera under the same settings. By using a MATLAB program, the grayscale of the selected area in each image was calculated. This value decreased steadily with increasing the temperature, and a significant change was observed at T. By plotting a graph of the second derivative of relative grayscale against temperature, the T of a polymer can be unambiguously determined from the lowest point. The present method shows performance comparable to that of conventional DSC measurement in terms of sensitivity and reliability. Besides, it can measure multiple samples in parallel, suggesting that ADEtect is a versatile technique with high commercial value and promising for high-throughput T measurement.

Qiu Zijie    Chu Eric K.K.    Jiang Meijuan    Gui Chen    Ni Xie    Wei Qin    Alam    Ryan tsz kin Kwok    林荣业    唐本忠    

Macromolecules

2017

Recent years have witnessed the significant role of anion-π interactions in many areas, which potentially brings the opportunity for the development of aggregation-induced emission (AIE) systems. Here, a new strategy that utilized anion-π interactions to block detrimental π-π stacking was first proposed to develop inherent-charged AIE systems. Two AIE-active luminogens, namely, 1,2,3,4-tetraphenyloxazolium (TPO-P) and 2,3,5-triphenyloxazolium (TriPO-PN), were successfully synthesized. Comprehensive techniques such as single-crystal analysis, theoretical calculation, and conductivity measurement were used to illustrate the effects of anion-π interactions on the AIE feature. Their analogues tetraphenylfuran (TPF) and 2,4,5-triphenyloxazole (TriPO-C) without anion-π interactions suffered from the aggregation-caused emission quenching in the aggregate state, demonstrating the important role of anion-π interactions in suppressing π-π stacking. TriPO-PN was biocompatible and could specifically target lysosome in fluorescence turn-on and wash-free manners. This suggested that it was a promising contrast agent for bioimaging.

Wang Jianguo    Xinggui Gu    Zhang Pengfei    Xiaobo Huang    Zheng Xiaoyan    Chen Ming    Feng Hai-Tao    Ryan tsz kin Kwok    林荣业    唐本忠    

Journal of the American Chemical Society

2017

In this study, a specifically-designed aggregation-induced emission fluorogen (AIEgen) with nanoparticle aggregates was used to quantitatively evaluate the bioaccumulation of Hgand visualize Hgkinetics in vivo within the rotifer Brachionus plicatilis for the first time. Quantitative results showed that a sharp drop in Hgconcentration occurred at the very beginning in the medium containing rotifers and Hg, showing a quick initial uptake of Hgby the rotifers, and then the concentration in the medium plateaued after 5 min. With an increase in rotifer density, the amount of bioaccumulation increased in the rotifer. However, the bioaccumulation efficiency of Hgdecreased from 5.28 μg mghat a low rotifer density of 0.093 mg mlto 2.61 μg mghat a high rotifer density of 0.375 mg mL. Moreover, the fluorescence images and spectra results illustrate that the ingestion of Hgby the rotifer was via its mouth surrounded by the ciliary corona to the digestive tract, and Hgcould not permeate into the body integument through diffusion during the study period. Hg-induced fluorescence in rotifers dissipated in 6 h after staining, possibly through defecation and excretion. This study indicates that inorganic mercury can be quickly ingested by a rotifer via feeding, but is unlikely deposited as methylated mercury in rotifer tissues.

Jiang Yusheng    He Tao    Chen Yuncong    Ruan Yinlan    Zhou Yabin    唐本忠     Jianguang Qin    Youhong Tang   

Environmental Science: Nano

2017

Paper-based assay is a promising alternative sensing technology due to its portability, low cost and ease of operation compared to the solution sensing method. Most of current fluorophores suffer from aggregation-caused quenching, which affects their signal output in the solid state. Although fluorogens with aggregation-induced emission (AIEgens) have attracted intense research interest for solution assays, they have been rarely employed for solid phase detection due to their high emissivity in the aggregated state. In this work, three fluorogens TPE-DCV, MTPE-DCV and NTPE-DCV were designed and synthesized by the integration of intramolecular charge transfer and AIE characteristics to fine-tune their absorption and emission maxima. Among the three AIEgens, NTPE-DCV gives the best response to hydrazine, with a detection limit of 143 ppb in solution. In addition, the NTPE-DCV stained paper strip offers fluorescence turn-on from dark to yellow for 1 mM hydrazine solution or 1% hydrazine vapor for naked-eye sensing. It was also found that the fluorogen with a stronger electron donor (e.g.NTPE-DCV) showed better selectivity to hydrazine over glutathione. The practical example of hydrazine detection elucidates a general strategy for the design of AIE probes that are compatible with both solution and paper-based assays with a high sensitivity and rapid signal readout.

Zhang Ruoyu    Chongjing Zhang    Zhegang Song    Jing Liang    Ryan tsz kin Kwok    唐本忠     Bin Liu   

Journal of Materials Chemistry C

2016

Fluorescent light-up probes with aggregation-induced emission (AIE) characteristics have recently attracted great research interest due to their intelligent fluorescence activation mechanism and excellent photobleaching resistance. In this work, we report a new, simple, and generic strategy to design and prepare highly sensitive AIE fluorescent light-up bioprobe through facile incorporation of a self-assembling peptide sequence GFFY between the recognition element and the AIE luminogen (AIEgen). After the bioprobes respond to the targets, the peptide GFFY is capable of inducing the ordered self-assembly of AIEgens, yielding close and tight intermolecular steric interactions to restrict the intramolecular motions of AIEgens for excellent signal output. Using two proof-of-concepts, we have demonstrated that self-assembling peptide-incorporating AIE light-up probes show much higher sensitivity in sensing the corresponding targets in both solutions and cancer cells as compared to those without GFFY induced self-assembly. Taking the probe TPE-GFFYK(DVEDEE-Ac), for example, a detection limit as low as 0.54 pM can be achieved for TPE-GFFYK(DVEDEE-Ac) in caspase-3 detection, which is much lower than that of TPE-K(DVED-Ac) (3.50 pM). This study may inspire new insights into the design of advanced fluorescent molecular probes. (Figure Presented).

Han Aitian    Huaimin Wang    Ryan tsz kin Kwok    Ji Shenglu    Li Jun    Deling Kong    唐本忠     Bin Liu    Zhimou Yang    Dan Ding   

Analytical Chemistry

2016