No abstract

The low oxygen dependence of type I photosensitizers (PSs) has made them a popular choice for treating solid tumors. However, the drawbacks of poor water solubility, short emission wavelength, poor stability, and inability to distinguish cancer cells from normal cells limit the application of most type I PSs in clinical therapy. Thereby, developing novel type I PSs for overcoming these problems is an urgent but challenging task. Herein, by utilizing the distinctive structural characteristics of anion‐π+ interactions, a highly water‐soluble type I PS (DPBC‐Br) with aggregation‐induced emission (AIE) characteristic and near‐infrared (NIR) emission is fabricated for the first time. DPBC‐Br displays remarkable water solubility (7.3 mM) and outstanding photobleaching resistance, enabling efficient and precise differentiation between tumor cells and normal cells in a wash‐free and long‐term tracking manner via NIR‐I imaging. Additionally, the superior type I reactive oxygen species (ROS) produced by DPBC‐Br provide both specific killing of cancer cells in vitro and inhibition of tumor growth in vivo, with negligible systemic toxicity. This study rationally constructs a highly water‐soluble type I PS, which has higher reliability and controllability compared with conventional nanoparticle formulating procedures, offering great potential for clinical cancer treatment.

Near-infrared (NIR) photosensitizers with rapid reactive oxygen species (ROS) production ability are in great demand owing to their promising performances toward boosting photodynamic therapy (PDT) and deep deep-tissue imaging, but...

The exploitation of ultralong organic room temperature phosphorescence (UORTP) materials lags far behind the need because of the lack of general design strategies. Here we proposed a facile design strategy...

Ovalene’s nitrogenated derivative with all zigzag edges and nitrogen atom doping at the periphery has been developed via one-step nitrogenation of formylbisanthene. Because of nitrogen incorporation, these molecules show greatly decreased highest occupied molecular orbital levels, enhanced intermolecular interactions, and a reversible acid response. Aza-ovalene also exhibits a diatropic ring current along the periphery. This work provides rare examples of all-zigzag-edged N-polycyclic aromatic hydrocarbons.

α-L-Rhamnosidase is a glycoside hydrolase capable of removing naringin from citrus juice. However, α-L-rhamnosidases always have broad substrate spectra, causing negative effects on citrus juice. In this study, a α-L-rhamnosidase-expressing fungal strain, JMU-TS529, was identified, and its α-L-rhamnosidase was characterized. As a result, JMU-TS529 was identified as Aspergillus tubingensis via morphological and molecular characteristics. The predicted protein sequence shared an amino acid identity of less than 30% with previously characterized α-L-rhamnosidases. The optimal pH and temperature were 4.0 and 50–60 °C, respectively. Most importantly, the α-L-rhamnosidase showed a strong ability to hydrolyze naringin but scarcely acted on other substrates. Furthermore, the enzyme could efficiently remove naringin from pomelo juice without changing its attractive aroma. These results indicate that the present enzyme represents a new clade of Aspergillus α-L-rhamnosidase that is desirable for debittering citrus juice, providing a better alternative for improving the quality of citrus juice.

α‐l‐Rhamnosidase is a biotechnologically important enzyme in food industry and in the preparation of drugs and drug precursors. To expand the functionality of our previously cloned α‐l‐rhamnosidase from Aspergillus niger JMU‐TS528, 14 mutants were constructed based on the changes of the folding free energy (ΔΔG), predicted by the PoPMuSiC algorithm. Among them, six single‐site mutants displayed higher thermal stability than wild type (WT). The combinational mutant K573V–E631F displayed even higher thermostability than six single‐site mutants. The spectra analyses displayed that the WT and K573V–E631F had almost similar secondary and tertiary structure profiles. The simulated protein structure‐based interaction analysis and molecular dynamics calculation were further implemented to assess the conformational preferences of the K573V–E631F. The improved thermostability of mutant K573V–E631F may be attributed to the introduction of new cation–π and hydrophobic interactions, and the overall improvement of the enzyme conformation. Practical applications The stability of enzymes, particularly with regards to thermal stability remains a critical issue in industrial biotechnology and industrial processing generally tends to higher ambient temperature to inhibit microbial growth. Most of the α‐l‐rhamnosidases are usually active at temperature from 30 to 60°C, which are apt to denature at temperatures over 60°C. To expand the functionality of our previously cloned α‐l‐rhamnosidase from Aspergillus niger JMU‐TS528, we used protein engineering methods to increase the thermal stability of the α‐l‐rhamnosidase. Practically, conducting reactions at high temperatures enhances the solubility of substrates and products, increases the reaction rate thus reducing the reaction time, and inhibits the growth of contaminating microorganisms. Thus, the improvement on the thermostability of α‐l‐rhamnosidase on the one hand can increase enzyme efficacy; on the other hand, the high ambient temperature would enhance the solubility of natural substrates of α‐l‐rhamnosidase, such as naringin, rutin, and hesperidin, which are poorly dissolved in water at room temperature. Protein thermal resistance is an important issue beyond its obvious industrial importance. The current study also helps in the structure–function relationship study of α‐l‐rhamnosidase.

Pathogenic bacteria infections, especially multidrug resistant bacteria infections have aroused worldwide attention due to their severe threats to human beings. Thus, the development of highly effective antibacterial reagents is very important. However, the design of antimicrobials is still quite challenging for the lack of a universal design strategy. Here, a synergistic manipulation strategy of dipole-dipole and anionπ + interaction is proposed for constructing highly efficient antimicrobials with aggregation-induced emission (AIE) feature. Firstly, four anion-π + -type AIE luminogens were de-signed and synthesized. Due to the electron-donating and hydrophilic characteristic of methoxy groups, 3MOTPO containing three methoxy groups showed the largest dipole moment (5.06 Debye) and dual anion-π + interactions in the solid state. Driven by both dipole-dipole and anion-π + interactions, 3MOTPO showed the strongest bacterial binding ability and the best antibacterial activities (MIC 90 = 3.76 μM). The work offers a deep insight into the rational design of highly efficient antimicrobials for luminescence-guided antibacterial study.