Search

Photodynamic therapy (PDT) has long been shown to be a powerful therapeutic modality for cancer. However, PDT is undiversified and has become stereotyped in recent years. Exploration of distinctive PDT methods is thus highly in demand but remains a severe challenge. Herein, an unprecedented 1+1+1>3 synergistic strategy is proposed and validated for the first time. Three homologous luminogens with aggregation-induced emission (AIE) characteristics were rationally designed based on a simple backbone. Through slight structural tuning, these far-red/near-infrared AIE luminogens are capable of specifically anchoring to mitochondria, cell membrane, and lysosome, and effectively generating reactive oxygen species (ROS). Notably, biological studies demonstrated combined usage of three AIE photosensitizers gives multiple ROS sources simultaneously derived from several organelles, which gives superior therapeutic effect than that from a single organelle at the same photosensitizers concentration. This strategy is conceptually and operationally simple, providing an innovative approach and renewed awareness of improving therapeutic effect through three-pronged PDT.

The discovery of relaxor behavior in poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymers plays a crucial role in driving the formation of a morphotropic phase boundary (MPB) near which large enhancements of dielectric and piezoelectric responses are achieved. Here we study the dielectric spectra of P(VDF-TrFE)s near MPB and analyze the relaxor behavior using two different theoretical models. We observe the largest dielectric constant of ∼76 at 1 kHz in morphotropic composition P(VDF-TrFE) 50/50 mol % at around 69 °C. We show that the compositional dependence of dielectric peak temperature changes dramatically in the vicinity of VDF = 49 mol %. Moreover, we find that the parameters (i.e., dielectric relaxation strength) deduced from the fit of the experimental data by different models also changes abruptly at VDF = 49 mol %. These findings clearly signify the destabilization of normal ferroelectric phase occurring at the critical VDF content of 49 mol % and explicitly mark one boundary of ...

Three cross-linked porphyrin-based polyimides (PPBPI-H-CR, PPBPI-Mn-CR, and PPBPI-Fe-CR) were synthesized from 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) and 2,5-bis(3,4-dicarboxyphenoxy)-4′-p...

Significantly enhanced electromechanical responses are inherent to piezoelectric materials at the morphotropic phase boundary (MPB). Here we reveal that conformational competition between the trans-planar and 3/1-helical phases of poly(vinylidene fluoride–trifluoroethylene) P(VDF-TrFE) occurs intramolecularly rather than intermolecularly to induce the formation of MPB. We attribute significantly enhanced piezoelectric properties observed near MPB to the polarization rotation between energetically degenerate trans-planar and 3/1-helical phases. Our results offer design principles to search for new MPB polymers from a molecular perspective.

Phototheranostics involving both fluorescence imaging and photodynamic therapy has been recognized to be potentially powerful for cancer treatment by virtue of various intrinsic advantages. However, the state-of-the-art materials in this area are still far from ideal toward practical applications, ascribed to their respective and collective drawbacks, such as inefficient imaging quality, inferior reactive oxygen species (ROS) production, the lack of subcellular-targeting capability, and dissatisfactory delivery. In this paper, these shortcomings are successfully addressed through the integration of finely engineered photosensitizers with aggregation-induced emission (AIE) features and well tailored nanocarrier systems. The yielded AIE NPs simultaneously exhibit broad absorption in the visible-light region, bright near-infrared fluorescence emission, high ROS generation, as well as tumor lysosomal acidity-activated and nucleus-targeted delivery functions, making them promising for precise and efficient phototheranostics. Both in vitro and in vivo evaluations show that the presented nanotheranostic systems bearing good photostability and appreciable biosecurity perform well in fluorescence imaging-guided photodynamic cancer therapy. This study thus not only extends the application scopes of AIE nanomaterials but also offers useful insights into constructing advanced cancer phototheranostics.

Biliary-stent implantation has become an effective treatment for patients with malignant obstructive jaundice caused by hepatobiliary carcinoma. Stent restenosis due to tumor ingrowth is a common problem. In this study, we assessed a biodegradable form of magnesium (Mg) for its anticancer effect on hepatobiliary carcinoma, compared to the conventional stent material of titanium (Ti). The results showed that a Mg extract inhibited proliferation and induced apoptosis in human cholangiocarcinoma cells, while a Mg plate inhibited cell adhesion and destroyed the cytoskeleton in the process of biodegradation. In animal experiments with H22 tumor-bearing mice, Mg wires implanted in tumors exhibited an inhibitory effect on their growth compared with Ti wires. Fifteen days after implantation of metal wires, the mean tumor volume and weight in the Mg group were significantly smaller than in the Ti group. We observed the dynamic-degradation process of Mg wires in tumors and generation of H

Effective landslide hazard prevention requires accurate landslide prediction models, and the data-driven approaches based on deep learning models are gradually becoming a hot research topic. When training deep learning models, it is always preferable to have a large dataset, while most available landslide monitoring data are limited. For data missing or data sparseness problems, conventional interpolation methods based on mathematical knowledge lack mechanism interpretability. This paper proposes that numerical simulations can be used to expand the deep learning dataset we need. Taking the Jiuxianping landslide in the Three Gorges Reservoir Area (TGRA) as the geological background, a finite element numerical model was established, and the landslide displacement time series data were solved considering the boundary conditions of reservoir water level change and precipitation. Next, based on three metrics: Euclidean distance, cosine similarity, and dynamic time warping (DTW) distance, the time series similarity between the displacement data obtained from simulation and data obtained from actual monitoring were verified. Finally, the combined deep learning model was built to predict the displacement of the Jiuxianping landslide. The model was trained on both the simulated and monitored datasets and tested by the last 12 monitored data points. Prediction results with the testing set showed that the models trained using the expanded training set from numerical simulations exhibited lower prediction errors, and the errors had a more concentrated distribution. The results suggest that this landslide displacement prediction method combining numerical simulation and deep learning can solve the problem of inadequate datasets due to low monitoring frequency, as well as provide an interpretation of the physical mechanism for data vacancy filling.

Phototheranostics involving both fluorescence imaging (FLI) and photodynamic therapy (PDT) has been recognized to be potentially powerful for cancer treatment by virtue of various intrinsic advantages. However, the state-of-the-art materials in this area are still far from ideal towards practical applications, owing to their respective and collective drawbacks, such as inefficient imaging quality, inferior reactive oxygen species (ROS) production, the lack of subcellular-targeting capability, and dissatisfactory theranostics delivery. In this contribution, these shortcomings are successfully addressed through the integration of finely engineered photosensitizers having aggregation-induced emission (AIE) features and well tailored nanocarrier system. The yielded AIE NPs simultaneously exhibit broad absorption in visible light region, bright near-infrared fluorescence emission, extremely high ROS generation, as well as tumor lysosomal acidity-activated and nucleus-targeted delivery functions, making them dramatically promising for precise and efficient phototheranostics. Both in vitro and in vivo evaluations show that the presented nanotheranostic system bearing excellent photostability and appreciable biosecurity well performed in FLI-guided photodynamic cancer therapy. This study thus not only extends the applications scope of AIE nanomaterials, but also offers useful insights into constructing a new generation of cancer theranostics.

Phototheranostics involving both fluorescence imaging (FLI) and photodynamic therapy (PDT) has been recognized to be potentially powerful for cancer treatment by virtue of various intrinsic advantages. However, the state-of-the-art materials in this area are still far from ideal towards practical applications, owing to their respective and collective drawbacks, such as inefficient imaging quality, inferior reactive oxygen species (ROS) production, the lack of subcellular-targeting capability, and dissatisfactory theranostics delivery. In this contribution, these shortcomings are successfully addressed through the integration of finely engineered photosensitizers having aggregation-induced emission (AIE) features and well tailored nanocarrier system. The yielded AIE NPs simultaneously exhibit broad absorption in visible light region, bright near-infrared fluorescence emission, extremely high ROS generation, as well as tumor lysosomal acidity-activated and nucleus-targeted delivery functions, making them dramatically promising for precise and efficient phototheranostics. Both in vitro and in vivo evaluations show that the presented nanotheranostic system bearing excellent photostability and appreciable biosecurity well performed in FLI-guided photodynamic cancer therapy. This study thus not only extends the applications scope of AIE nanomaterials, but also offers useful insights into constructing a new generation of cancer theranostics.

A composite foam consisting of foamed cross-linking polystyrene (c-PS) and boron nitride nanosheets (BNNSs) was synthesized, which shows a higher thermal conductivity (TC) than the corresponding solid counterparts. The BNNS fillers are found to be aligned along the cell wall as a result of the biaxial stress field from cell expansion during the formation of three-dimensional interconnectivity in the foams, resulting in an enhanced TC of 1.28 W/m K, nearly two and four times those of its solid counterpart and pure c-PS, respectively. It is found that the foaming-assisted formation of the filler network is an efficient strategy to improve the TC at low filler loadings in the composites. Furthermore, the composite foams exhibit low density, rather low dielectric constants and dissipation factors at wide frequency and temperature ranges. The present work provides a novel approach to design and prepare lightweight heat conductive polymers with low filler loadings as low-density heat management materials for potential applications in aeronautics and aerospace components.

The development of advanced dielectric materials with high breakdown strength, high dischargeable energy densities, and great efficiencies is imperative to meet the ever-increasing demand of modern power systems and electronic devices. Herein, we present the layer-by-layer solution prepared bilayer-structured nanocomposite films with much enhanced capacitive performance via resolving the typical paradox between dielectric constant and breakdown strength in dielectric materials. The bilayered nanocomposite films are composed of Al2O3 dispersed in polystyrene as the interfacial barrier layer to inhibit electrical conduction and the polystyrene layer with TiO2 to enhance dielectric constant. The resulting layered film exhibits a discharged energy density of 4.43 J/cm3 along with ultrahigh charge−discharge efficiencies of >90%, which is among the highest energy densities ever achieved in the polystyrene-based dielectric polymer nanocomposites. In addition, the composite films show outstanding cyclic stability under high electric fields, which would enable the long-term efficient operation of film capacitors. This contribution represents an efficient route to high-energy-density dielectric composite materials by using interfacial barrier architectures.

Facile synthesis and bio-applications of a series of AIEgens with widely tunable emissions ranging from violet to near-infrared are reported., Luminogens with aggregation-induced emission (AIE) characteristics are nowadays undergoing explosive development in the fields of imaging, process visualization, diagnosis and therapy. However, exploration of an AIE luminogen (AIEgen) system allowing for extremely wide color tunability remains challenging. In this contribution, the facile synthesis of triphenylamine (TPA)–thiophene building block-based AIEgens having tunable maximum emission wavelengths covering violet, blue, green, yellow, orange, red, deep red and NIR regions is reported. The obtained AIEgens can be utilized as extraordinary fluorescent probes for lipid droplet (LD)-specific cell imaging and cell fusion assessment, showing excellent image contrast to the cell background and high photostability, as well as satisfactory visualization outcomes. Interestingly, quantitative evaluation of the phototherapy effect demonstrates that one of these presented AIEgens, namely TTNIR, performs well as a photosensitizer for photodynamic ablation of cancer cells upon white light irradiation. This study thus provides useful insights into rational design of fluorescence systems for widely tuning emission colors with high brightness, and remarkably extends the applications of AIEgens.

Aiming to achieve versatile phototheranostics with the integrated functionalities of multiple diagnostic imaging and synergistic therapy, the optimum use of dissipated energy through both radiative and nonradiative pathways is definitely appealing, yet a significantly challenging task. To the best of the knowledge, there have been no previous reports on a single molecular species effective at affording all phototheranostic modalities including fluorescence imaging (FLI), photoacoustic imaging (PAI), photothermal imaging (PTI), photodynamic therapy (PDT), and photothermal therapy (PTT). Herein, a simple and highly powerful one-for-all phototheranostics based on aggregation-induced emission (AIE)-active fluorophores is tactfully designed and constructed. Thanks to its strong electron donor-acceptor interaction and finely modulated intramolecular motion, the AIE fluorophore-based nanoparticles simultaneously exhibit bright near-infrared II (NIR-II) fluorescence emission, efficient reactive oxygen species generation, and high photothermal conversion efficiency upon NIR irradiation, indicating the actualization of a balance between radiative and nonradiative energy dissipations. Furthermore, the unprecedented performance on NIR-II FLI-PAI-PTI trimodal-imaging-guided PDT-PTT synergistic therapy is demonstrated by the precise tumor diagnosis and complete tumor elimination outcomes. This study thus brings a new insight into the development of superior versatile phototheranostics for practical cancer theranostics.

To achieve efficient and precise design of fluorescent probes, unraveling the intrinsic mechanism of their selectivity on different subcellular organelles in cell imaging is important. Using a theoretical protocol combining large-scale molecular dynamics simulations and the hybrid QM/MM model, we explored the mechanism of the strikingly different fluorescence imaging behaviors of two amphiphilic AIEgens with quite similar chemical structures. We proposed that the hydrophobic moiety and the pyridine group of AIEgens manipulate the emission behaviors, and the charged headgroups control the permeation ability through the cell membrane. Therefore, we proposed a molecular design strategy of AIEgen-based fluorescent probes to selectively target the cell membrane or mitochondria, and designed and synthesized four AIEgens. The cell imaging experimental results successfully confirmed the theoretical prediction, which would open an efficient shortcut to design AIEgen-based fluorescent probes to selectively target the cell membrane or mitochondria and lays a solid foundation for the rational design of advanced cell imaging materials.

Fluorescence-based theranostics provides a powerful platform for effective diagnosis and therapy. In particular, luminogens with aggregation-induced emission (AIE) characteristics have triggered state-of-the-art developments in theranostics, thanks to their intrinsic properties, including high signal-to-noise ratios, high photostability and capability as photosensitizing agents. However, the development of AIE luminogens for biological applications mostly stays at rational design and preparation through organic synthesis, which may give rise to high cost, environmental destruction and potential cytotoxicity. Actually, with easy access and good biocompatibility, it would be of great interest to employ AIE-active natural agents from herbs in theranostics and pharmacodynamics studies through fluorescence imaging. In this work, the use of berberine chloride, an AIE-active natural product from herbal plants, as a theranostic agent towards both cancer cells and bacteria is investigated. Through fluorescence bio-imaging, berberine chloride selectively targets cancer cells over normal cells and discriminates Gram-positive against Gram-negative bacteria. Furthermore, light-driven organelle-targeting migration of berberine chloride from mitochondria to the nucleus was discovered. Therapeutic evaluation shows that berberine chloride can efficiently ablate cancer cells over normal cells, and kill Gram-positive bacteria through both in vitro and in vivo photodynamic therapy. This work thus provides a blueprint for the next generation of theranostics using natural AIE luminogens.

Two sets of thermal stable nanocomposites were fabricated by using engineering plastics poly(ether sulfone) (PES) as a matrix and phthalocyanine molecules (CuPc) or hyperbranched phthalocyanine (HCuPc)-coated barium titanate (BT) nanoparticles as fillers for high electric field and high-temperature dielectric applications. By side-by-side comparison, the hyperbranched coating is finely addressed for enhancing the dielectric response and breakdown strength of the composites. Specifically, BT–HCuPc/PES exhibits 40% lower dielectric loss and about 110% larger breakdown strength than BT–CuPc/PES. The addition of hyperbranched phthalocyanine may enhance the compatibility and dispersion of the ceramic fillers in the polymer matrix and reduces the charge carrier between the filler and matrix. Meanwhile, high dielectric constant, high breakdown, and low dielectric loss are well-maintained in the composites filled with hyperbranched phthalocyanine-modified BT from room temperature to 150 °C. The discharged energy ...

A novel ultrafiltration membrane is developed by incorporating in situ self-assembled polymeric nanoparticles into the membrane matrix. The chemical stability of the nanoparticles in regard to pH and temperature is explored via a rational method. The result indicates that the electrostatic interaction strength between the two polyelectrolytes can withstand a broad pH range (pH 1–11) and a relatively high temperature (80 °C). Meanwhile, the nanoparticle size and distribution in the membranes are investigated by scanning electron microscopy (SEM), which are proved to be affected by the polyelectrolyte concentration and molecular weight. The contact angle values of the prepared membranes show that the membrane hydrophilicity is improved by adding polymeric nanoparticles. Furthermore, the molecular weight cut-off and pore size of the membranes are increased with added nanoparticle loading. More importantly, the mixed matrix membranes exhibit simultaneous increases in permeability and rejection of contaminants compared with the pristine PES membrane, which is ascribed to the appropriate pore size and enhanced hydrophilicity of the membranes. Especially, the composite membrane mixed with 3 wt% polymeric nanoparticles displays the highest pure water flux (460 L m−2 h−1), which is 3 times that of the pristine PES membrane, and 97.6% rejection of BSA. This work provides a new strategy for preparing flexible polymeric nanoparticles and developing high-performance mixed matrix membranes for water treatment.

Local recurrence has become the main problem of tumor thermal ablation for hepatocellular carcinoma (HCC). Nanotechnology could potentially aid in improving the situation. MoS₂ nanomaterials, as ideal photothermal therapy (PTT) agents, have gathered great interest due to their excellent surface plasmon resonance features, high photothermal conversion efficiency, good biocompatibility and low cost. In this work, we synthesized layered MoS₂ hollow spheres (LMHSs; diameter ∼300 nm) via the solvent-controlled ultrasonic nebulization method. Compared to LMHSs previously synthesized by our group (approx. 600 nm), the current ones showed better efficacy, as well as enhanced permeability and retention, due to their ideal size. In addition, the LMHSs are developed with both layered and hollow structures, which are extremely suitable for loading anticancer agents. In this study, doxorubicin (DOX) was loaded into the nanoparticles (NPs) using the vacuum negative pressure loading method, and the drug loading capacity was as high as 32.5%. Therefore, the efficacy of cancer cell killing by photothermal ablation was markedly enhanced by DOX released from the LMHSs. As we expected, the as-made DOX@MoS₂ NPs exhibited excellent photothermo-chemotherapy effect, both in vitro and in vivo. Tumor cell viability was inhibited up to 73% at the power density of 1.2 W cm-2, and tumors in mice models achieved complete response, with no recurrence. The PTT with DOX@MoS₂ NPs had a much better synergistic therapeutic efficacy than each individual treatment, showing great promise for HCC treatment.

In this study, a polymeric composite with high-k, low dielectric loss, and high electrical energy storage has been developed by dispersing tetra-amido-phthalocyanine zinc (ZnPc) coated acidified multi-walled carbon nanotubes (a-MWCNT) within the sulfonated poly (ether ether ketone) (SPEEK) polymer matrix. The ZnPc-MWCNT/SPEEK composites exhibited better dielectric properties than pure polymer matrix, with a dielectric constant of 14.0 and a dielectric loss of 0.042 at 1 kHz (with 12 wt% ZnPc-MWCNT). Furthermore, the discharged energy density of ZnPc-MWCNT/SPEEK composites (4 wt% ZnPc-MWCNT) is 68% higher than that of the pure polymer.

High-temperature ceramic/polymer nanocomposites with large energy density as the reinforcement exhibit great potential for energy storage applications in modern electronic and electrical power systems. Yet, a general drawback is that the increased dielectric constant is usually achieved at the cost of decreased breakdown strength, thus leading to moderate improvement of energy density and even displaying a marked deterioration under high temperatures and high electric fields. Herein, a new strategy is reported to simultaneously improve breakdown strength and discharged energy density by a step-by-step, controllable dual crosslinking process, which constructs a strengthened interface as well as reduces molecular chains relaxation under elevated temperatures. Great breakdown strength and discharged energy density is achieved in the dual crosslinked network BT-BCB@DPAES nanocomposites at elevated temperatures when compared to noninterfacial-strengthened, BT/DPAES composites, i.e., an enhanced breakdown strength and a discharged energy density of 442 MV m-1 and 3.1 J cm-3 , increasing by 66% and 162%, and a stable cyclic performance over 10 000 cycles is demonstrated at 150 °C. Moreover, the enhancement through the synergy of two crosslinked networks is rationalized via a comprehensive phase-field model for the composites. This work offers a strategy to enhance the electric storage performances of composites at high temperatures.

Relaxor ferroelectrics exhibit outstanding dielectric, electromechanical and electrocaloric properties, and are the materials of choice for acoustic sensors, solid-state coolers, transducers and actuators1-4. Despite more than five decades of intensive study, relaxor ferroelectrics remain one of the least understood material families in ferroelectric materials and condensed matter physics5-14. Here, by combining X-ray diffraction, atomic force microscope infrared spectroscopy and first-principles calculations, we reveal that the relaxor behaviour of ferroelectric polymers originates from conformational disorder, completely different from classic perovskite relaxors, which are typically characterized by chemical disorder. We show that chain chirality is essential to the formation of the disordered helix conformation arising from local distortions of gauche torsional angles, which consequently give rise to relaxor properties in polymers. This study not only sheds light on the fundamental mechanisms of relaxor ferroelectrics, but also offers guidance for the discovery of new ferroelectric relaxor organic materials for flexible, scalable and biocompatible sensor and energy applications.

Bacterial infectious diseases, especially those caused by Gram-positive bacteria, have been seriously threatening human health. Preparation of a multifunctional system bearing both rapid bacterial differentiation and effective antibacterial effects is highly in demand, but remains a severe challenge. Herein, we rationally designed and successfully developed a sequence of aggregation-induced emission luminogens (AIEgens) with orderly enhanced D-A strength. Evaluation of structure-function relationships reveals that AIEgens having intrinsic positive charge and proper ClogP value are able to stain Gram-positive bacteria. Meanwhile, one of the presented AIEgens (TTPy) can generate reactive oxygen species (ROS) in extraordinarily high efficiency under white light irradiation due to the smaller singlet-triplet energy gap. Thanks to the NIR emission, excellent specificity to Gram-positive bacteria, and effective ROS generation efficiency, TTPy has been proved to perform well in selective photodynamic killing of Gram-positive bacteria in vitro, such as S. aureus and S. epidermidis, even in S. aureus-infected rat wounds.

Local recurrence has become the main problem of tumor thermal ablation for hepatocellular carcinoma (HCC). Nanotechnology could potentially aid in improving the situation. MoS₂ nanomaterials, as ideal photothermal therapy (PTT) agents, have gathered great interest due to their excellent surface plasmon resonance features, high photothermal conversion efficiency, good biocompatibility and low cost. In this work, we synthesized layered MoS₂ hollow spheres (LMHSs; diameter ∼300 nm) via the solvent-controlled ultrasonic nebulization method. Compared to LMHSs previously synthesized by our group (approx. 600 nm), the current ones showed better efficacy, as well as enhanced permeability and retention, due to their ideal size. In addition, the LMHSs are developed with both layered and hollow structures, which are extremely suitable for loading anticancer agents. In this study, doxorubicin (DOX) was loaded into the nanoparticles (NPs) using the vacuum negative pressure loading method, and the drug loading capacity was as high as 32.5%. Therefore, the efficacy of cancer cell killing by photothermal ablation was markedly enhanced by DOX released from the LMHSs. As we expected, the as-made DOX@MoS₂ NPs exhibited excellent photothermo-chemotherapy effect, both

Polymer dielectrics are ubiquitous in advanced electric energy storage systems. However, the relatively low operating temperature significantly menaces their widespread application at high temperatures, such as for hybrid vehicles and aerospace power electronics. Spider silk, a natural nanocomposite comprised of biopolymer chains and crystal protein nanosheets combined by multiple interfacial interactions, exhibits excellent mechanical properties even at elevated temperatures. Inspired by the hierarchical nanostructure of spider silk, poly(aryl ether sulfone) is anchored to the surface of wide bandgap artificial nanosheets to prepare the nanocomposites with nanoconfinement effect. The bioinspired strategy successfully improves the mechanical and electrical performances of the nanocomposite. Owing to the structural-enabled enhancements, the nanocomposites exhibit excellent breakdown strength and electrical energy storage performance at high temperatures. In detail, giant discharged energy density (2.7 J cm-3 ) and high charge-discharge efficiency (>90%) are simultaneously achieved at 150 °C and 400 MV m-1 . Notably, under 500 MV m-1 , the discharged energy density reaches 4.2 J cm-3 , which is the record high discharged energy density among polymer-based dielectrics at 150 °C. This work demonstrates a viable strategy to design high-temperature polymer dielectrics by constructing nanoconfinement in the nanocomposites.

Construction of single component theranostic agent with one-for-all features to concurrently afford both multi-modality imaging and therapy is an appealing yet significantly challenging task. Herein, a type of luminogens with aggregation-induced emission (AIE) characteristics are tactfully designed and facilely synthesized. These AIE luminogens (AIEgens) exhibit long emission wavelengths, good photostability, remarkable biocompatibility, good reactive oxygen species (ROS) generation performance and excellent photothermal conversion efficiency, which allow them to be powerfully utilized for in vitro and in vivo cancer phototheranostics. The results show that one of the AIEgens is capable of precisely diagnosing solid tumors of mice by means of combined near-infrared-I/II (NIR-I/II) fluorescence-photoacoustic imaging, meanwhile this AIEgen can activate photodynamic and photothermal synergistic therapy (PDT-PTT) upon laser irradiation, resulting in excellent tumor elimination efficacy with only once injection and irradiation. This study thus provides a versatile platform for practical cancer theranostics.

The efficient utilization of energy dissipating from non-radiative excited-state decay of fluorophores was only rarely reported. Herein, we demonstrate how to boost the energy generation of non-radiative decay and use it for cancer theranostics. A novel compound (TFM) was synthesized which possesses a rotor-like twisted structure, strong absorption in the far red/near-infrared region, and it shows aggregation-induced emission (AIE). Molecular dynamics simulations reveal that the TFM aggregate is in an amorphous form consisting of disordered molecules in a loose packing state, which allows efficient intramolecular motions, and consequently elevates energy dissipation from the pathway of thermal deactivation. These intrinsic features enable TFM nanoparticles (NPs) to display a high photothermal conversion efficiency (51.2 %), an excellent photoacoustic (PA) effect, and effective reactive oxygen species (ROS) generation. In vivo evaluation shows that the TFM NPs are excellent candidates for PA imaging-guided phototherapy.

Piezoelectricity—the direct interconversion between mechanical and electrical energies—is usually remarkably enhanced at the morphotropic phase boundary of ferroelectric materials1–4, which marks a transition region in the phase diagram of piezoelectric materials and bridges two competing phases with distinct symmetries1,5. Such enhancement has enabled the recent development of various lead and lead-free piezoelectric perovskites with outstanding piezoelectric properties for use in actuators, transducers, sensors and energy-harvesting applications5–8. However, the morphotropic phase boundary has never been observed in organic materials, and the absence of effective approaches to improving the intrinsic piezoelectric responses of polymers9,10 considerably hampers their application to flexible, wearable and biocompatible devices. Here we report stereochemically induced behaviour in ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) copolymers, which is similar to that observed at morphotropic phase boundaries in perovskites. We reveal that compositionally tailored tacticity (the stereochemical arrangement of chiral centres related to the TrFE monomers11,12) can lead to intramolecular order-to-disorder evolution in the crystalline phase and thus to an intermediate transition region that is reminiscent of the morphotropic phase boundary, where competing ferroelectric and relaxor properties appear simultaneously. Our first-principles calculations confirm the crucial role of chain tacticity in driving the formation of this transition region via structural competition between the trans-planar and 3/1-helical phases. We show that the P(VDF-TrFE) copolymer with the morphotropic composition exhibits a longitudinal piezoelectric coefficient of −63.5 picocoulombs per newton, outperforming state-of-the-art piezoelectric polymers10. Given the flexibility in the molecular design and synthesis of organic ferroelectric materials, this work opens up the way for the development of scalable, high-performance piezoelectric polymers.

Polymer/CNT (carbon nanotube) composites with a high dielectric constant show great potential for energy storage applications. However, these CNT-based composites usually suffer from high dielectric loss and low breakdown strength, and pose difficulties in the tailoring of the dielectric constant. The integration of a CNT cladding insulator filler layer into the polymers provides an effective way to reach a low dielectric loss and a high breakdown strength. But the insulator layer could significantly reduce the dielectric constant, thereby decreasing the energy storage density of composites. Herein, we have designed and fabricated a novel candidate composed of a semiconductor NH2–CuPc coated multi-walled carbon nanotube (MWCNT-CuPc) through chemical grafting, in which dielectric CuPc layers can act not only as insulation barriers for suppressing leakage current, but also as semi-conductor layers to partially block electron motion. Thus the as-prepared composites exhibit not only a higher dielectric constant but also extremely decreased dielectric loss and excellent dielectric strength. Moreover, the dielectric properties of the composites can be easily tuned by tailoring the loading of MWCNT-CuPc. Our strategy provides a new pathway to achieve polymer/CNT composites with high dielectric performances for energy storage applications.

The first water-soluble NIR AIEgen was synthesized and used for ultrafast wash-free cellular imaging and photodynamic cancer cell ablation., The synthesis of water-soluble near-infrared (NIR)-emissive fluorescent molecules with aggregation-induced emission (AIE) characteristics and theranostic functions is highly desirable but remains challenging. In this work, we designed and readily prepared for the first time such a molecule with AIE features, good water-solubility and intense emission in the NIR region. This AIE luminogen (AIEgen) is able to specifically “light up” the cell membrane without the involvement of a washing procedure. Interestingly, the staining process can be performed by simply shaking the culture with cells at room temperature for only a few seconds after the addition of the AIEgen, indicating an ultrafast and easy-to-operate staining protocol. This is the first fluorescent “light-up” probe for cell-imaging that allows the combination of a short staining period (at the second-level) with a wash-free process. Additionally, the presented AIEgen has also been developed to serve as an excellent phototherapeutic agent for high efficiency generation of reactive oxygen species (ROS) upon visible light irradiation, which allows its effective application in the photodynamic ablation of cancer cells, demonstrating its dual role as an imaging and phototherapeutic agent.

With the increase of bacterial infections in clinical practice, it becomes a public health problem which has aroused worldwide attention. Fluorescence imaging-guided photodynamic antibiosis has recently emerged as a promising protocol to solve this problem. However, developing a super powerful fluorescent material allowing facile preparation, long emission wavelength, rapid bacterial discrimination, washing-free staining, and high photodynamic antibacterial efficiency in a single entity, is highly desirable but remains challenging. In this study, we utilize for the first time a water-soluble near-infrared (NIR) emissive luminogen with aggregation-induced emission (AIE) characteristics, namely TTVP, for simultaneous dual applications of Gram-positive bacteria discrimination and photodynamic antibiosis. TTVP is able to selectively target Gram-positive bacteria over Gram-negative bacteria through a washing-free procedure after only 3 s incubation period, which is at least 100-fold shorter than those of previously reported protocols, implying ultrafast bacterial discrimination features. Meanwhile, TTVP exhibits extremely high reactive oxygen species generation efficiency, which is far superior to that of most popularly used photosensitizers, representing one of the best candidates for photodynamic antibiosis. In vitro and in vivo results demonstrate that TTVP provides extraordinary performance on photodynamic antibacterial therapy. This study thus offers a blueprint for the next generation of antibacterial materials.

Carbon nanotube (CNT)/polymer composites with high dielectric constants are highly desired by the electronic and electric industries. However, high conductivity CNTs exhibit bad dispersion properties in polymers, leading to high dielectric losses in the composites. One effective strategy to overcome these problems involves the fabrication of core–shell structured fillers with CNT cores and non-conductive or semi-conductive shells. In this study, tetra-amido-phthalocyanine copper (4NH 2 -CuPc) coated, acidified multi-walled carbon nanotube (a-MWCNT) composites were fabricated through π–π stacking interactions. The coating thickness was controlled by adjusting the concentration of 4NH 2 -CuPc in the mixture and was subsequently confirmed by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analyses. The a-MWCNTs/4NH 2 -CuPc were added to poly(vinylidene fluoride) (PVDF) to produce a-MWCNTs/4NH 2 -CuPc/PVDF composites. The dielectric properties of these composites reached the optimum values when the rate of 4NH 2 -CuPc adsorption on the a-MWCNTs was the highest. A composite with 9 wt% a-MWCNTs and 13.5 wt% 4NH 2 -CuPc (mass ratio a-MWCNTs:4NH 2 -CuPc = 1:1.5) exhibited the largest dielectric constant (3200) and a dielectric loss tangent (2.1 at 1 kHz).