Combining Chitosan, Stearic Acid, and (Cu-, Zn-) MOFs to Prepare Robust Superhydrophobic Coatings with Biomedical Multifunctionalities.

There is an urgent need to develop a series of multifunctional materials with good biocompatibility, high mechanical strength, hemostatic properties, antiadhesion, and anti-infection for applications in wound care. However, successfully developing multifunctional materials is challenging. In this study, two superhydrophobic composite coatings with good biocompatibility, high mechanical strength, strong antifouling and blood repellency, fast hemostasis, and good antibacterial activity are prepared on cotton fabric surface by simple, green, and low-cost one-step dip-coating technology. The results discussed in the manuscript reveals that the two superhydrophobic composite coatings can maintain good mechanical stability, strong water repellency, and durability under various types of mechanical damage, high-temperature treatment, and long-term strong light irradiation. The coatings also exhibit good repellency to various solid pollutants, highly viscous liquid pollutants, and blood. In vitro and in vivo hemostatic experiments show that both composite coatings have good hemostatic and anticlot adhesion properties. More importantly, this superhydrophobic coating prevents bacterial adhesion and growth and released Cu2+ and Zn2+ ions and chitosan to achieve bactericidal properties, thereby protecting injured skin from bacterial infection. The two superhydrophobic coatings enhance the antifouling, antiadhesion, hemostatic, and antibacterial functions of blood-repellent dressings and therefore have broad application prospects in medical and textile fields.

Rough Endoplasmic Reticulum Inspired Polystyrene-Brush-Based Superhigh Sulfur Content Cathodes Enable Lithium-Sulfur Cells with High Mass and Capacity Loading.

The development of highly sophisticated biomimetic models is significant yet remains challenging in the electrochemical energy storage field. Lithium-sulfur (Li-S) cells with high sulfur content and high-sulfur-loading cathodes are urgently required to meet the fast-growing demand for electronic devices. Nevertheless, such cathode materials generally suffer from large sulfur agglomeration, nonporous structure, and insufficient conductivity, leading to rapid capacity decay and low sulfur utilization. Herein, inspired by rough endoplasmic reticulum, a 2D polystyrene (PS)-brush-based (G-g-PS) superhigh-sulfur-content (96 wt%) composite(G-g-sPS@S) is fabricated via the vulcanization reaction. The vulcanized PS side-chains and their S8 composites on the nanosheet surface can efficiently provide sulfur species, and the intersheet interstitial pores can provide rapid mass-transfer channels for redox reactions of sulfur species. Furthermore, the highly sulfophilic vulcanized PS side-chains are able to effectively inhibit the shuttle effect of polysulfides and regulate their redox process. With these merits, the cells with G-g-sPS@S cathodes exhibit an ultralow decay rate of 0.02% per cycle over 400 cycles at 2 C and deliver a superior areal capacity of 12.6 mAh cm-2 even with a high sulfur loading of 10.5 mg cm-2 .

Construction of Hierarchical Micro/Nanostructured ZnO/Cu-ZnMOFs@SA Superhydrophobic Composite Coatings with Excellent Multifunctionality of Anticorrosion, Blood-Repelling, and Antimicrobial Properties.

Naked medical devices are often damaged by blood, bacteria, and other extreme environmental conditions (heat, humidity, acid, alkali, salts, and others), causing device failure and increasing difficulty for the operator. They can also cause inflammation and coagulation resulting in severe complications and even death. In this work, the superhydrophobic ZnO/copper-zinc metal-organic frameworks@stearic acid (ZnO/Cu-ZnMOFs@SA) composite coatings with hierarchical micro/nanostructures were fabricated on Zn substrates via a one-step hydrothermal method. The effects of hierarchical micro/nanostructures on surface wettability, physicochemical stability, and biological properties have been studied in this manuscript. The structure not only provided the coatings with robust waterproofing, abrasive resistance, durability, and thermal and light irradiation stability but also successfully recovered their superhydrophobicity by remodifying the surface with SA, showing excellent repeatability. In addition, the coating demonstrates excellent corrosion resistance and self-cleaning ability and rejects various solid and liquid contaminants. The superhydrophobic ZnO/Cu-ZnMOFs@SA composite coatings also exhibited excellent antibacterial and thrombosis resistance. The findings indicated that the superhydrophobic composite coatings have a strong potential for application in medical instruments for exhibiting multifunctional properties in various extreme environments.

NO released via both a Cu-MOF-based donor and surface-catalyzed generation enhances anticoagulation and antibacterial surface effects.

The anticoagulation and antibacterial functions of implant and interventional catheters during indwelling will determine their success or failure. Here, an amino-containing copper-based metal-organic framework (Cu-MOF) coating was prepared on the thermoplastic polyurethane substrate (TPU) surface by spin coating for anti-thrombotic and anti-infection effects. The adhesion properties of the polyurethane prepolymer coating (PC) enhanced the binding force of Cu-MOF particles and TPU surface and improved stability. Due to the coordination affinity of Cu2+ with nitric oxide (NO) and the NO loading capacity of the amino group, it showed that a large amount of NO was loaded in the coating. Meanwhile, the coordinated Cu2+ in the coating also catalyzed endogenous NO donors to generate NO, which prolonged the NO release for up to 30 days. The results of antibacterial experiments showed that the NO released from the coating had good antibacterial effects on both E. coli and S. epidermidis. An obvious antibacterial ring can be seen and the antibacterial rate was higher than 96%. It also showed inhibiting platelet adhesion and activation, prolonged in vitro clotting time and inhibited thrombus formation. In summary, for the first time, NO release from the coating was realized by the combined ways of NO donor and catalytic endogenous NO donor. It can not only meet the high NO release rate required for early anticoagulation and antibacterial of the catheter but also maintain normal anticoagulation requirements in the later period.

Stearic acid modified nano CuMOFs used as a nitric oxide carrier for prolonged nitric oxide release.

Nitric oxide (NO) shows high potential in the cardiovascular system with anticoagulant and antibacterial efficacy. Cu based metal organic frameworks with amino modification (CuMOFs) were found to have an extraordinary high NO loading, but at the expense of framework stability in ambient moisture. Nano CuMOFs was synthesized by hydrothermal method in this work, and treated with stearic acid (SA) creating a hydrophobic form. It was found that the structure of the particles was not affected after treatment with SA, and the treated CuMOFs had tunable hydrophobicity. Both CuMOFs and SA modified CuMOFs adsorbed NO with the reaction of the amino group and NO to form a NONOate. SA modification enhanced stability of the CuMOFs in phosphate buffer solution (PBS, pH = 7.4), slowed down the interaction between the NO loading unit and H2O, and thus NO releasing was prolonged. The resulting NO-loaded CuMOFs inhibited platelet activation dramatically, prolonged the coagulation time and displayed excellent antibacterial properties. They could be envisioned as a good candidate for application in blood contacting implants.

Self-Supporting Electrocatalyst Film Based on Self-Assembly of Heterogeneous Bottlebrush and Polyoxometalate for Efficient Hydrogen Evolution Reaction.

Developing efficient electrocatalysts to promote the hydrogen evolution reaction (HER) is essential for a green and sustainable future energy supply. For practical applications, it is a challenge to achieve the self-assembly of electrocatalyst from microscopic to macroscopic scales. Herein, a facile strategy is proposed to fabricate a self-supporting electrocatalyst film (CNT-g-PSSCo/PW12 ) for HER by electrostatic interaction-induced self-assembly of cobalt polystyrene sulfonate-grafted carbon nanotube heterogeneous bottlebrush (CNT-g-PSSCo) and polyoxometalate (PW12 ). Co2+ ions of CNT-g-PSSCo can function as junctions for interconnecting neighboring bottlebrushes to form the 3D nanonetwork structure and enable electrostatic capture of negatively charged PW12 nanodots. Moreover, CNT backbones can provide highly conductive pathways to CNT-g-PSSCo/PW12 . Such a self-assembled CNT-g-PSSCo/PW12 displays a low overpotential of 31 mV at a current density of 10 mA cm-2 and a small Tafel slope of 25 mV dec-1 , showing high efficiency toward HER. Furthermore, CNT-g-PSSCo/PW12 with a stable self-supporting film morphology exhibits long-term electrocatalytic stability over 1000 CV cycles without noticeable overpotential change in acidic media. The findings may provide a new avenue for constructing self-assembled functional nanonetwork materials with well-orchestrated structural hierarchy for many applications in energy, environment, catalysis, medicine, and others.