Dual-Porosity Hollow Carbon Spheres with Tunable Through-Holes for Multi-Guest Delivery

Study of oxygen-deficient W18O49-based drug delivery system readily absorbed through cellular internalization pathways in tumor-targeted chemo-/photothermal therapy

W₁₈O₄₉-mediated photothermal therapy (PTT) is affected by the easily oxidized property and its direct exposure to physiological environment can cause biological events, which limit its development in the biomedical field. Herein, a composite nanoparticle PVP-W₁₈O₄₉@C (PW@C), with significant antioxidant and excellent biocompatibility, was constructed to overcome the limitations of W₁₈O₄₉ in the medical field. Oxygen-deficient W₁₈O₄₉, with irregular defect structure, was combined with hollow carbon nanospheres treated by reflux to obtain W₁₈O₄₉@C (W@C) similar to sea urchins. Compared with W₁₈O₄₉, W@C shows stronger antioxidant properties, and it still has the ability to convert light energy to heat energy after 6 months. In addition, polyvinyl pyrrolidone is coated on the surface of W@C to construct PW@C, which significantly improves biocompatibility of W@C. The photothermal conversion efficiency of PW@C was 42.9 ± 1.3. PWD (PW@C loaded with DOX·HCl) showed controllable drug release behavior under pH and NIR stimulation, and the drug release rate reached 69.1 ± 1.6% at pH = 5.0. Notably, PWD was readily absorbed by cells through clathrin/caveolae-mediated internalization channels, and the viability of HeLa cells treated with PWD + NIR was only 21.5 ± 1.0%. Through photothermal, drug delivery/release and cytotoxicity evaluation, PWD was proved to be an effective platform for chemo-/photothermal combinational tumor therapy.

Silk-Waste-Derived Porous Carbon for Fast Electric Heating under Safe Voltage

Fast and safe electric heating is highly needed in extreme climates or thermal therapy. Herein, porous activated carbon derived from silk waste is prepared by a simple method. Various porous activated carbons are obtained using different types and concentrations of activator (KOH, KCl, and KHCO₃). The effect of the microstructure on the electric heating performance of these carbons is investigated carefully. The type, activator concentration, and carbonization temperature play key roles in the regulation of electric heating properties. The porous carbon activated by 0.05 M KHCO₃ at 800 °C demonstrates larger specific surface area (3077 m² g^-1), higher graphitization degree, and lower resistance (2.4 Ω cm), which synergistically contribute greatly to its higher electrothermal efficiency and better electric heating performance. The equilibrium temperature could reach 73 °C in 2 min under a safe voltage of 12 V, proving the better pore-forming capacity and activating function of KHCO₃. An electric heating cotton@carbon composite fabric with quite good electric heating property and stability is also prepared, which could reach 38 °C in 2 min under 12 V safe voltage and maintain a temperature 10 °C higher than the ambient temperature even when bent at an angle of 55°. This activated carbon derived from waste protein using a simple and cheap process has great potential in practical applications.

Design of a Smart Self-Healing Coating with Multiple-Responsive Superhydrophobicity and Its Application in Antibiofouling and Antibacterial Abilities

Inspired by the restoration of the superhydrophobic surfaces after the damage in nature such as lotus leaf and clover, smart self-healing coating with controllable release of loaded healing agents is both of scientific and technological interest. Herein, a smart self-healing coating with superhydrophobicity was gained through blending UV/NIR/acid/base multiple-responsive ZnO-encapsulated mesoporous polydopamine (MPDA) microspheres (zinc oxide-encapsulated mesoporous polydopamine microspheres) with silicone latex and hydrophobic nanoparticles. The hydrophobic and micro/nanostructured ZnO-encapsulated MPDA microspheres provided UV/NIR/acid/base multiple response sources for the smart self-healing coating, combining the photocatalytic activity and acid/base solubility of ZnO nanoparticles, zwitterionic characteristic of amino-modified silicone oil (ASO), as well as the photothermal conversion abilities and charge characteristics of PDA. The ZnO nanoparticles simultaneously acted as the protective layer for the stimuli-responsive microspheres and functional filler in the coating, contributing to realize the controllable and long-period release of loaded hydrophobic ASO and the further antibacterial functionalization for the coating. The super/high hydrophobicity and antibiofouling performances of the coating could be self-healed by UV, NIR, acid, or base stimuli, attributing to the release of ASO from the microspheres. Then, large-area, rapid, and controllable healing superiority could be achieved on the coating with the combined multiple responses under different conditions. Robust environmental endurances for superhydrophobic coating were also confirmed under harsh environments by directly exposing to UV-accelerated weathering and immersing into various solutions (including strong acid/base, salt, and artificial seawater solution). This smart coating has high application prospects due to its environmentally friendly nature, excellent self-healing, and multifunctional characteristics, and the multiple-responsive ZnO-encapsulated MPDA microspheres can be used for the functionalization of other materials.

Yolk-Shell Carbon Nanospheres with Controlled Structure and Composition by Self-Activation and Air Activation

Yolk-shell carbon nanospheres (YSCNs) have raised a great deal of interest due to the synergistic advantages over their counterparts. However, it is still difficult to precisely regulate the morphology, porosity, and composition of YSCNs. Here, N-doped porous YSCNs were synthesized via an in situ self-activation by pyrolysis of polypyrrole encapsulated hyper-cross-linked polystyrene (HPS@PPy) core-shell nanospheres, followed by a mild air activation treatment. During the self-activation process, the polypyrrole shell of HPS@PPy provided a confinement effect for the morphology transformation from the core-shell to the yolk-shell structure. The air activation exhibited simultaneous control over porosity and composition. The preparation parameters, such as shell thickness and air activation conditions, were modified to optimize the structure and surface composition of YSCNs to achieve optimal electrochemical performances.

Effect of eggshell membrane as porogen on the physicochemical structure and protease immobilization of chitosan-based macroparticles

Chitosan-based macroparticle is a common carrier for enzyme immobilization applied in food industry. Driven by the requirement of large carrier pores for the biomacromolecular substrates such as protein, the eggshell membrane powder (ESMP) was employed as multifunctional porogen to improve the physicochemical structure of chitosan-based macroparticles. The prepared macroparticles were characterized by SEM, XRD, FTIR, Raman spectroscopy, nitrogen adsorption-desorption isotherms, and thermogravimetric analysis. The results showed that an increase of ESMP percentage could improve the porosity of macro holes in macroparticles, and it also enlarged the size of mesopores. Moreover, the ESMP significantly increased (P < 0.05) the amount of papain immobilization, whereas the specific activity of immobilized papain achieved a maximum value of 871.95 U/mg at CSESM2 and then declined with the increase of ESMP. Therefore, the inclusion of 20 % ESMP in chitosan-based macroparticles gave the highest activity of its immobilized protease.

Synthesis of a Porous C3N-Derived Framework with High Yield by Gallic Acid Cross-Linking Using Salt Melts

Porous carbon/nitrogen frameworks are an emerging class of noble organic materials with a wide range of potential applications. However, the design and controlled synthesis of those materials are still a challenge. Herein, we present the rational design of such a system with high microporosity, specific surface areas of up to 946 m² g^-1, and excellent condensation yields. The obtained noble frameworks were used for the delivery of larger organic molecules and changed the melting behavior of some daily drug molecules along their highly polarizable surfaces.