Two blue-emitting materials, 4-(12-([1,1\':3\',1″-terphenyl]-5\'-yl)chrysen-6-yl)-N,N-diphenylaniline (TPA-C-TP) and 6-([1,1\':3\',1″-terphenyl]-5\'-yl)-12-(4-(1,2,2-triphenylvinyl)phenyl)chrysene (TPE-C-TP), were prepared with the composition of a chrysene core moiety and terphenyl (TP), triphenyl amine (TPA), and tetraphenylethylene (TPE) moieties as side groups. The maximum photoluminescence (PL) emission wavelengths of TPA-C-TP and TPE-C-TP were 435 and 369 nm in the solution state and 444 and 471 nm in the film state. TPA-C-TP effectively prevented intermolecular packing through the introduction of TPA, a bulky aromatic amine group, and it showed an excellent photoluminescence quantum yield (PLQY) of 86% in the film state. TPE-C-TP exhibited aggregation-induced emission; the PLQY increased dramatically from 0.1% to 78% from the solution state to the film state. The two synthesized materials had excellent thermal stability, with a high decomposition temperature exceeding 460 °C. The two compounds were used as emitting layers in a non-doped device. The TPA-C-TP device achieved excellent electroluminescence (EL) performance, with Commission Internationale de L\'Eclairage co-ordinates of (0.15, 0.07) and an external quantum efficiency of 4.13%, corresponding to an EL peak wavelength of 439 nm.

Alzheimer\'s disease (AD), an amyloid-related disease, seriously endangers the health of elderly individuals. According to current research, its main pathogenic factor is the amyloid protein, which is a kind of fibrillar aggregate formed by noncovalent self-assembly of proteins. Based on the characteristics of aggregation-induced emission (AIE), a bislactosyl-decorated tetraphenylethylene (TPE) molecule TMNL (TPE + malononitrile + lactose), bearing two malononitrile substituents, was designed and synthesized in this work. The amphiphilic TMNL could self-assemble into fluorescent organic nanoparticles (FONs) with near-infrared (NIR) fluorescence emission in physiological PBS (phosphate buffered saline), achieving excellent fluorescent enhancement (47-fold) upon its combination with Aβ1-42 fibrils. TMNL was successfully applied to image Aβ1-42 plaques in the brain tissue of AD transgenic mice, and due to the AIE properties of TMNL, no additional rinsing process was necessary. It is believed that the probe reported in this work should be useful for the sensitive detection and accurate localization mapping of Aβ1-42 aggregates related to Alzheimer\'s disease.

We synthesized a new tetraphenylethylene-modified chitosan bioconjugate, CS-TPE, that shows the aggregation-induced emission effect. It can self-assemble into fluorescent polymeric nanoparticles in an aqueous solution at pH 5.3 either alone or with the water-soluble bowl-shaped six-fold carboxylated tribenzotriquinacene derivative TBTQ-C6 via host-guest binding. The spherical nanoparticles formed by CS-TPE amphiphiles or TBTQ-C6/CS-TPE supra-amphiphiles disintegrated under alkaline stimulation at pH 10.4 and the dispersion of the aggregates after the collapse in the presence of TBTQ-C6 was greatly improved. In addition, the fluorescence of CS-TPE was significantly enhanced by introducing TBTQ-C6, and remained relatively stable with variations in pH for both CS-TPE and TBTQ-C6/CS-TPE. Such pH-responsive supramolecular spherical nanoparticles with stable fluorescence emission based on CS-TPE or TBTQ-C6/CS-TPE may find applications in various fields, including the development of visual oral drug delivery systems.

In this work, a dispersible graphene-based material with a characteristic of aggregation-induced emission (AIE) was prepared by wet chemical reduction of graphene oxide (GO). During the GO reduction process, a conjugated molecule TPEP containing tetraphenylethylene (TPE) and pyrene was employed as a stabilizer because of the π-π interactions and the wrapping effect. The as-prepared rGO-TPEP not only has good dispersion in solution but also processes the AIE feature. Its fluorescence intensity is 2.23 times higher than that of TPEP at the same condition. The unique optical properties and AIE effect enable the rGO-TPEP as a chemical sensor for highly sensitive explosive detection in aggregated state and solid state. In the aggregated state, trace 2,4-dinitrotoluene (DNT) can be detected by the rGO-TPEP even when the concentration is as low as 0.91 ppm, and the quenching constant is as high as 2.47 × 104 M-1.

Mesenchymal stem cells (MSCs), due to their tumor tropism, are strongly recruited by various solid tumors and mobilized by inflammatory signals in the tumor microenvironment. However, effective cellular uptake is critical for MSC-based drug delivery. In this study, we synthesized a spherical copolymer, polyethylenimine-poly(ε-caprolactone), with aggregation-induced emission (AIE) material and the anticancer drug, paclitaxel, coloaded onto its inner core. This was followed by the addition of a transactivator of transcription (TAT) peptide, a type of cell-penetrating peptide, to modify the nanoparticles (NPs). Finally, the MSCs were employed to carry the TAT-modified AIE-NPs drug to the tumor sites and assist in simultaneous cancer diagnosis and targeted tumor therapy. In vitro, the TAT-modified AIE-NPs showed good biocompatibility, targeting, and stability in an aqueous solution besides high drug-loading and encapsulation efficiency. In vitro, the AIE-NPs exhibited a controllable release under a mildly acidic environment. The in vivo and in vitro studies showed high antitumor efficacy and low cytotoxicity of the AIE-NP drug, whereas biodistribution confirmed the tumor tropism of MSCs. To summarize, the MSC-based AIE-NP drugs loaded with TAT possessed good biocompatibility and high antitumor efficacy via the enhanced NP-drug uptake. In addition, the tumor tropism of MSCs provided selective drug uptake by the tumor cells and thus reduced the systemic side effects.

A flexible chemosensor has been developed based on colorimetric and fluorescent dual modes using tetraphenylethylene-centered tetraaniline (TPE4A) for rapid and sensitive detection of hypochlorite anion. The fluorescent probe TPE4A exhibits a unique aggregation-induced emission (AIE) character which is proved by a blue shift of the fluorescent peak from 544 to 474 nm with the water equivalents increasing. With the addition of hypochlorite in solution, the absorbance of the probe changes and the responding fluorescence color can be observed to change from light green to purple. The detection limit of hypochlorite is 1.80 × 10-4 M in solution, and the visual detection limit is 1.27 µg/cm2 with the naked eye for the flexible paper-based chemosensor. The proposed flexible chemosensors show a good selectivity and sensitivity which has great potential for effective detection of hypochlorite anions without any spectroscopic instrumentation.

Tetraphenylethylene (TPE) and its derivatives exhibit excellent aggregation-induced emission (AIE) properties. The TPE unit is easily accessible, and many functional groups can be introduced in a facile manner to yield effective luminescent materials in both solution and the solid-state. It is because of this, several TPE-based compounds have been developed and applied in many areas, such as OLEDs and chemical sensors. Boron dipyrromethenes (BODIPYs) are a class of pyrrolic fluorophore of great interest with myriad application in both material science and biomedical applications. Through the combination of Pd-catalyzed cross-coupling reactions and traditional dipyrromethene chemistry, we present the syntheses of novel tetra-BODIPY-appended TPE derivatives with different distances between the TPE and BODIPY cores. The TPE-BODIPY arrays 6 and 9 show vastly differing AIE properties in THF/H2O systems, with 9 exhibiting dual-AIE, along with both conjugates being found to produce singlet oxygen (1O2). We presume the synthesized BODIPY-appended TPE scaffolds to be utilized for potential applications in the fields of light-emitting systems and theranostics.

Tetraphenylethylene (TPE), a typical luminogen with aggregation-induced emission (AIE) features, has been widely used to prepare AIE fluorescent materials. In this study, TPE-functionalized polydimethylsiloxane (n-TPE-AP-PDMS) was successfully synthesized by attaching TPE to polydimethylsiloxane via aza-Michael addition. The introduction of polydimethylsiloxane to TPE had no obvious effect on photophysical properties. Intriguingly, n-TPE-AP-PDMS exhibited two opposite fluorescence emission behaviors in different systems: aggregation-induced quenching (ACQ) behavior in a tetrahydrofuran/water mixture and typical AIE phenomenon in a tetrahydrofuran/hexane mixture. This unexpected transition from ACQ to AIE can be attributed to a twisted intramolecular charge-transfer effect and flexible aminopropyl polydimethylsiloxane. n-TPE-AP-PDMS was further used as a fluorescent probe to detect nitrobenzene and it showed high quenching efficiency. Moreover, the n-TPE-AP-PDMS film showed high reversibility so that the quenching efficiency remained constant after five cycles. This work can provide a deeper understanding of AIE behavior and guidance to develop a new AIE polymer for chemosensors with high performance.

In this work, we first designed and synthesized tetraphenylene-fused aryl-imidazole derivatives TM-1-4 via regulation of molecular structure, which were consisted of 1H-imidazo[4,5-f][1,10]phenanthroline, 1H-phenanthro[9,10-d]imidazole, 4,5-diphenyl-1H-imidazole, 3,3\'-(1H-imidazole-4,5-diyl)dipyridine moieties and AIE-active tetraphenylethene units, respectively. The results illustrated that TM-1-4 exhibited clear AIE characteristics. Meanwhile, TM-2 and TM-3 show excellent solid emission properties (ΦTM-2 =13.73 % and ΦTM-3 =36.21 %), whereas TM-1 and TM-4 exhibit the opposite properties (ΦTM-1 =1.48 % and ΦTM-4 =4.83 %). The multiple rotors (pyridine and benzene ring) causes twisted conformations of the molecule that prevents π-π stacking and enhances solid emission(ΦTM-2<ΦTM-3, ΦTM-1<ΦTM-4). Significantly, TM-2 and TM-3 also exhibited reversible mechanochromic behavior (Emission red shifts: ΔλTM-2 =43 nm and ΔλTM-3 =41 nm) with color changes between blue and green emissions. The powder X-ray diffraction (PXRD) suggested the disordered state of ground sample could be readily returned to an ordered crystalline. Therefore, the mechanochromisms of TM-2 and TM-3 are ascribable to the phase transformation between crystal and amorphous structure. The single crystal X-ray analysis of TM-2 reveals a twisted conformation for TPE moiety and the absence of π-π intermolecular stacking. These excellent optical properties of TM-2 and TM-3 make them potentially applications in mechanochromic materials and imaging agents.

Two small molecular monomers, ph-TPE and ph-TPE-CN, and their homopolymers Poly (ph-TPE) and Poly (ph-TPE-CN) containing tetra phenylethylene and sulfate structures, were synthesized by a sulfur (VI) fluorine exchange click reaction (SuFEx) and radical polymerization. All the monomers and polymers exhibit a typical aggregation-induced emission (AIE) effect both in the solid state and aggregated state. Moreover, based on the intermolecular charge transfer (ICT) effect between the tetra phenylethylene chromophore and p-nitrophenol, both polymers could be used for the selective detection of p-nitrophenol. The detection limit and reactivity coefficient of Poly (ph-TPE) are 0.081 μM and 5.15×104  M-1 , respectively, whereas the detection limit and reactivity coefficient of Poly (ph-TPE-CN) are 0.077 μM and 1.81×104  M-1 , respectively. This can be attributed to the greater sensitivity of Poly (ph-TPE-CN) to p-nitrophenol than that of Poly (ph-TPE). This work provides a new methodology for the preparation and broadening application of side-chain type AIE-active polysulfate fluorescent probes.