Zincke’s Salt-Substituted Tetraphenylethylenes for Fluorometric Turn-On Detection of Glutathione and Fluorescence Imaging of Cancer Cells

In this paper, we report Zincke’s salt-substituted tetraphenylethylenes <b>1a</b> and <b>1b</b> with Cl^– and PF₆^– as counteranions, respectively. The crystal structure of <b>1b</b> was determined. Both <b>1a</b> and <b>1b</b> are almost nonemissive even in the aggregated states. This is attributed to the photoinduced electron transfer from 2,2-bis­(4-methoxyphenyl)-1-phenylvinyl-phenyl unit to 1-(2,4-dinitrophenyl) pyridinium unit within <b>1a</b> and <b>1b</b>. The results demonstrate that the emissions of <b>1a</b> and <b>1b</b> in aqueous solution can be switched on upon either reaction with GSH or light irradiation. On the basis of the reaction between <b>1a</b> and GSH, <b>1a</b> can be utilized for the fluorescence turn-on detection of GSH selectively, and GSH with concentration as low as 36.9 nM can be detected. The transformation of <b>1b</b> into <b>2</b> under light irradiation results in the fluorescence imaging of Hela and U2OS cells and phototoxicity toward Hela and U2OS cells after the protonation of pyridine unit in <b>2</b> because of the acidic environment of tumor cells. Aggregates of <b>1b</b> can be up-taken by Hela and U2OS cells and fluorescence imaging has been successfully recorded with CLSM. Moreover, the protonated form of <b>2</b> can function as photosensitizer and <b>1b</b> shows phototoxicity toward tumor cells such as Hela and U2OS cells

Highly Sensitive Thin-Film Field-Effect Transistor Sensor for Ammonia with the DPP-Bithiophene Conjugated Polymer Entailing Thermally Cleavable <i>tert</i>-Butoxy Groups in the Side Chains

The sensing and detection of ammonia have received increasing attention in recent years because of the growing emphasis on environmental and health issues. In this paper, we report a thin-film field-effect transistor (FET)-based sensor for ammonia and other amines with remarkable high sensitivity and satisfactory selectivity by employing the DPP-bithiophene conjugated polymer pDPPBu-BT in which <i>tert</i>-butoxycarboxyl groups are incorporated in the side chains. This polymer thin film shows <i>p</i>-type semiconducting property. On the basis of TGA and FT-IR analysis, <i>tert</i>-butoxycarboxyl groups can be transformed into the −COOH ones by eliminating gaseous isobutylene after thermal annealing of pDPPBu-BT thin film at 240 °C. The FET with the thermally treated thin film of pDPPBu-BT displays remarkably sensitive and selective response toward ammonia and volatile amines. This can be attributed to the fact that the elimination of gaseous isobutylene accompanies the formation of nanopores with the thin film, which will facilitate the diffusion and interaction of ammonia and other amines with the semiconducting layer, leading to high sensitivity and fast response for this FET sensor. This FET sensor can detect ammonia down to 10 ppb and the interferences from other volatile analytes except amines can be negligible

Improving Ambipolar Semiconducting Properties of Thiazole-Flanked Diketopyrrolopyrrole-Based Terpolymers by Incorporating Urea Groups in the Side-Chains

Two new ambipolar thiazole-flanked diketopyrrolopyrrole-based polymers pDPPTz2T-1 and pDPPTz2T-2 with urea-containing linear side-chains were prepared. The formation of hydrogen bonding enhanced the ambipolar semiconducting properties, including mobilities and on/off ratios. The average mobilities (hole and electron) of pDPPTz2T-2 were 25 and 3 times higher than those of pDPPTz2T without urea groups, whereas the average on/off ratios (<i>I</i>_on/<i>I</i>_off) for hole and electron were 100 and 4 times higher than those obtained for pDPPTz2T. Thin-film microstructure studies reveal that incorporating urea groups into polymer side-chains can enhance interchain packings, including the alkyl chain lamellar and π–π stackings. Our results clearly show how incorporating urea groups in side-chains significantly influence semiconducting properties, which could be extended to other conjugated systems toward ambipolar and even n-type FETs

Aggregation-Induced Emission Nanoparticles Encapsulated with PEGylated Nano Graphene Oxide and Their Applications in Two-Photon Fluorescence Bioimaging and Photodynamic Therapy <i>in Vitro</i> and <i>in Vivo</i>

Aggregation-induced emission (AIE) nanoparticles have been shown promise for fluorescence bioimaging and photodynamic therapy due to the good combination of nanoparticles and organic dyes or photosensitizers. Among several kinds of AIE nanoparticles, those that are capsulated with nanographene oxides (NGO) are easy to make, size-tunable, and have proven to be very stable in deionized water. However, the stability in saline solution still needs improvement for further applications in chemical or biomedical fields, and the efficacy of photodynamic therapy using NGO-capsulate AIE photosensitizers has not been evaluated yet. Herein, we modified NGO with polyethylene glycol (PEG) to improve the stability of NGO-capsulated AIE nanoparticles in phosphate buffer saline. Furthermore, by combining this modification method with a dual-functional molecule which has both typical AIE property and photosensitizing ability, we performed both two-photon fluorescence bioimaging and photodynamic therapy <i>in vitro</i> and <i>in vivo</i>. Our work shows that AIE nanoparticles capsulated with PEGylated nanographene oxide can be a powerful tool for future bioimaging and photodynamic therapy applications

Self-Assembled Nanostructures Based on Activatable Red Fluorescent Dye for Site-Specific Protein Probing and Conformational Transition Detection

Smart and versatile nanostructures have demonstrated their effectiveness for biomolecule analysis and show great potential in digging insights into the structural/functional relationships. Herein, a nanoscale molecular self-assembly was constructed for probing the site-specific recognition and conformational changes of human serum albumin (HSA) with tunable size and emission. A tetraphenylethylene derivative TPE-red-COOH was used as the building block for tailoring fluorescence-silent nanoparticles. The highly specific and sensitive response to HSA was witnessed by the fast turn-on of the red fluorescence and simultaneous disassembly of the nanostructures, whereas various endogenous biomolecules cannot induce such response. The mechanism investigation indicates that the combination of multiple noncovalent interactions is the driving force for disassembling and trapping TPE-red-COOH into HSA. The resultant restriction of intramolecular rotation of TPE-red-COOH in the hydrophobic cavity of HSA induces the significant red emission. By using the fluorescence activatable nanosensor as the structural indicator, the stepwise conformational transitions of HSA during denaturing and the partial refolding of subdomain IIA of HSA were facilely visualized. Benefiting from its activatable signaling, sensitivity, and simplicity, such molecular assembly provides a kind of soft nanomaterial for site-specific biomolecule probing and conformational transition detection concerning their structure, function, and biomedical characteristics

Bioinspired Peptide for Imaging Hg²⁺ Distribution in Living Cells and Zebrafish Based on Coordination-Mediated Supramolecular Assembling

Peptides with modular structure provide a tailorable platform for constructing responsive supramolecular assemblies, which are attractive as functional biomaterials and smart sensors. In this work, the feasibility of regulating small peptides assembly with molecular design and metal ion recognition was demonstrated. Tripeptides were designed and found to have diverse response and self-assembly behavior to Hg²⁺. The incorporation of an aggregation-induced emission fluorophore TPE enabled the visualization of Hg²⁺ recognition and the assembly phenomenon. A structural analogue (Pep<b>2</b>) to γ-glutathione was identified with high specificity and nanomolar response to Hg²⁺ both in buffer solution and living cells. Driven by the coordination force and noncovalent intramolecular stacking, assembling of twisted nanofibers from Pep<b>2</b>-TPE and Hg²⁺ were observed. Benefiting from its biocompatibility, fast and switchable fluorescence response, Pep<b>2</b>-TPE was applied for imaging and monitoring Hg²⁺ distribution in living cells and zebrafish. With good permeability to plasma membrane and tissues, Pep<b>2</b>-TPE indicated the preferential distribution of Hg²⁺ in cell nucleoli and brain of zebrafish, which is related with the deleterious effect of inorganic mercury in living biosystems

Alternating Conjugated Electron Donor–Acceptor Polymers Entailing Pechmann Dye Framework as the Electron Acceptor Moieties for High Performance Organic Semiconductors with Tunable Characteristics

In this paper, we report the design, synthesis and semiconducting behavior of two conjugated D–A polymers <b>P-BPDTT</b> and <b>P-BPDBT</b> which entail <b>BPD</b>, a Pechmann dye framework, as electron accepting moieties, and thieno­[3,2-<i>b</i>]­thiophene and 2,2′-bithiophene as electron donating moieties. Their HOMO/LUMO energies and bandgaps were estimated based on the respective cyclic voltammgrams and absorption spectra of thin films. <b>P-BPDTT</b> possesses lower LUMO level and narrower bandgap than <b>P-BPDBT</b>. On the basis of the characterization of the field-effect transistors, a thin film of <b>P-BPDTT</b> exhibits ambipolar semiconducting properties with hole and electron mobilities reaching 1.24 cm² V^–1 s^–1 and 0.82 cm² V^–1 s^–1, respectively, after thermal annealing. In comparison, thin film of <b>P-BPDBT</b> only shows <i>p</i>-type semiconducting behavior with hole mobility up to 1.37 cm² V^–1 s^–1. AFM and XRD studies were presented to understand the interchain arrangements on the substrates and the variation of carrier mobilities

Additional file 1 of Inhibition of valve mesenchymal stromal cell calcium deposition by bFGF through alternative polyadenylation regulation of the CAT gene

Supplementary material 1

Fluorescence Turn-On Chemosensor for Highly Selective and Sensitive Detection and Bioimaging of Al³⁺ in Living Cells Based on Ion-Induced Aggregation

Herein, a new fluorescence turn-on chemosensor 2-(4-(1,2,2-triphenylvinyl)­phenoxy)­acetic acid (TPE-COOH) specific for Al³⁺ was presented by combining the aggregation-induced-emission (AIE) effect of tertaphenylethylene and the complexation capability of carboxyl. The introduction of carboxylic group provides the probe with good water-solubility which is important for analyzing biological samples. The recognition toward Al³⁺ induced the molecular aggregation and activated the blue fluorescence of the TPE core. The high selectivity of the probe was demonstrated by discriminating Al³⁺ over a variety of metal ions in a complex mixture. A detection limit down to 21.6 nM was determined for Al³⁺ quantitation. Furthermore, benefiting from its good water solubility and biocompatibility, imaging detection and real-time monitoring of Al³⁺ in living HeLa cells were successfully achieved. The AIE effect of the probe enables high signal-to-noise ratio for bioimaging even without multiple washing steps. These superiorities make this probe a great potential for the functional study and analysis of Al³⁺ in complex biosystems