Abstract
Pathogenic drug-resistant bacteria represent a threat to human health, for instance, the methicillin-resistant
Staphylococcus aureus
(MRSA). There is an ever-growing need to develop ...non-antibiotic strategies to fight bacteria without triggering drug resistance. Here, we design a hedgehog artificial macrophage with atomic-catalytic centers to combat MRSA by mimicking the “capture and killing” process of macrophages. The experimental studies and theoretical calculations reveal that the synthesized materials can efficiently capture and kill MRSA by the hedgehog topography and substantial generation of •O
2
−
and HClO with its Fe
2
N
6
O catalytic centers. The synthesized artificial macrophage exhibits a low minimal inhibition concentration (8 μg/mL Fe-Art M with H
2
O
2
(100 μM)) to combat MRSA and rapidly promote the healing of bacteria-infected wounds on rabbit skin. We suggest that the application of this hedgehog artificial macrophage with “capture and killing” capability and high ROS-catalytic activity will open up a promising pathway to develop antibacterial materials for bionic and non-antibiotic disinfection strategies.
Cancer is one of the most serious diseases endangering human health. In view of the side effects caused by chemotherapy and radiotherapy, it is necessary to develop low-toxic anti-cancer compounds. ...Polyphenols are natural compounds with anti-cancer properties and their application is a considerable choice. Pro-senescence therapy is a recently proposed anti-cancer strategy and has been shown to effectively inhibit cancer. It is of great significance to clarify the mechanisms of polyphenols on tumor suppression by inducing senescence. In this review, we delineated the characteristics of senescent cells, and summarized the mechanisms of polyphenols targeting tumor microenvironment and inducing cancer cell senescence for cancer prevention and therapy. Although many studies have shown that polyphenols effectively inhibit cancer by targeting senescence, it warrants further investigation in preclinical and clinical studies.
Besides the pandemic caused by the coronavirus outbreak, many other pathogenic microbes also pose a devastating threat to human health, for instance, pathogenic bacteria. Due to the lack of ...broad‐spectrum antibiotics, it is urgent to develop nonantibiotic strategies to fight bacteria. Herein, inspired by the localized “capture and killing” action of bacteriophages, a virus‐like peroxidase‐mimic (V‐POD‐M) is synthesized for efficient bacterial capture (mesoporous spiky structures) and synergistic catalytic sterilization (metal–organic‐framework‐derived catalytic core). Experimental and theoretical calculations show that the active compound, MoO3, can serve as a peroxo‐complex‐intermediate to reduce the free energy for catalyzing H2O2, which mainly benefits the generation of •OH radicals. The unique virus‐like spikes endow the V‐POD‐M with fast bacterial capture and killing abilities (nearly 100% at 16 µg mL–1). Furthermore, the in vivo experiments show that V‐POD‐M possesses similar disinfection treatment and wound skin recovery efficiencies to vancomycin. It is suggested that this inexpensive, durable, and highly reactive oxygen species (ROS) catalytic active V‐POD‐M provides a promising broad‐spectrum therapy for nonantibiotic disinfection.
A bioinspired, spiky, and highly catalytic‐active virus‐like peroxidase‐mimic (V‐POD‐M) is synthesized for the localized “capture and killing” eradication of pathogenic bacteria. Experimental and theoretical calculations demonstrate that the V‐POD‐M exhibits strong bacterial interactions and efficient capture, synergistic catalytic sterilization, and similar in vivo disinfection efficiency to that of vancomycin, which provides a promising broad‐spectrum therapy for nonantibiotic disinfection.
In this paper, the characters of hydrodynamic permeability, surface property, and blood compatibility of polydopamine (PDA) coated polyethersulfone (PES) ultrafiltration (UF) membranes were ...investigated in detail. We presented a general protocol to improve the hydrodynamic permeability and blood compatibility of PES UF membranes by a simple biomimetic strategy. The chemical structure and surface morphology of the PDA coated membranes were studied in detail; meanwhile, the influence of the coated PDA nano-layer on water contact angle and water flux of the modified membranes was investigated. It was found that the water flux of the pure PES membrane decreased dramatically, approach to 0ml/(m2hmmHg), after a few hours of PDA coating. To avoid the dramatic decline of water flux, the method of pre-adding pore-forming reagent was taken to fabricate the PDA coated PES membranes with tunable water flux. Moreover, the anti-fouling property, platelet adhesion, and blood coagulation time of the PDA modified PES membranes were studied, and the results indicated that the PDA modified PES UF membranes showed enhanced blood compatibility.
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► Polydopamine was used to improve hydrophilicity and hemocompatibility of PES membrane. ► The chemical structure and surface morphology of the coated PDA layer were studied. ► The modified membranes showed enhanced anti-fouling ability and blood compatibility.
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The design of self-sterilizing surfaces with favorable biocompatibility is acknowledged as an effective approach to deal with the bacterial infections of biomedical devices. In this ...study, we report an intriguing protocol for the large-scale fabrication of self-sterilizing and biocompatible surface film coatings by using polymer shielded silver nanoparticle loaded oxidized carbon nanotube (AgNPs@oCNT) nano-dispersions. To achieve the antibacterial coatings, the bioinspired positively charged and negatively charged AgNPs@oCNTs were alternately deposited onto substrates by spray-coating assisted layer-by-layer assembly. Then the bacterial inhibitory zones, optical density value monitoring, bacterial killing efficiency and adhesion were investigated; and all the results revealed that the AgNPs@oCNTs thin film coatings exhibited robust and long-term antibacterial activity against both Gram negative and Gram positive bacteria. Moreover, due to the shielding effects of polymer layers, the coatings showed extraordinary blood compatibility and limited toxicity against human umbilical vein endothelial cells. It is believed that the proposed large-scale fabrication of bactericidal, blood and cell compatible AgNPs@oCNT based thin film coatings will have great potential to forward novel operational pathogenic inhibition strategies to avoid undesired bacterial contaminations of biomedical implants or biological devices.
Bacterial infection of medical devices has been considered to be a world-wide clinical threat towards patients’ health. In this study, a bioinspired and biocompatible antibacterial coating was prepared via the spray-assisted layer-by-layer (LbL) assembly. The silver nanopartilces loaded oxidized carbon nanotube (AgNPs@oCNT), which were coated by functional polymers (chitosan and synthetic heparin mimicking polymers), were prepared via mussel inspired chemistry; and the spray-assisted assembly process allowed the fast construction on devices. Owing to the antibacterial efficiency of the loaded AgNPs, the coating showed robust bacterial killing activity and resistance towards bacterial adhesion. Moreover, since that the AgNPs were shielded by the polymers, the coating exhibited no clear toxicity at blood or cellular level. Benefiting from the universal and large-scale fabrication advancements of the spray assisted LbL coating; it is believed that the proposed strategy can be applied in designing many other kinds of self-sterilizing biomedical implants and devices.
An amphiphilic triblock co-polymer of poly(vinyl pyrrolidone)–b-poly(methyl methacrylate)–b-poly(vinyl pyrrolidone) (PVP-b-PMMA-b-PVP) was synthesized via reversible addition–fragmentation chain ...transfer (RAFT) polymerization. The block co-polymer can be directly blended with polyethersulfone (PES) using dimethylacetamide (DMAC) as the solvent to prepare flat sheet and hollow fiber membranes using a liquid–liquid phase separation technique. The PVP block formed a brush on the surface of the blended membrane, while the PMMA block mingled with the PES macromolecules, which endowed the membrane with permanent hydrophilicity. After adding the as-prepared block co-polymer the modified membranes showed lower protein (bovine serum albumin) adsorption, suppressed platelet adhesion, and a prolonged blood coagulation time, and thereby the blood compatibility was improved. Furthermore, the modified PES membranes showed good cytocompatibility, ultrafiltration and protein anti-fouling properties. These results suggest that surface modification of PES membranes by blending with the amphiphilic triblock co-polymer PVP-b-PMMA-b-PVP allows practical application of these membranes with good biocompatibility in the field of blood purification, such as hemodialysis and bioartificial liver support.
Combining the advantages of the fibrous nanostructure of carbon nanotubes (CNTs) and the bioactivities of heparin/heparin-mimicking polyanions, functional nanofibrous heparin or heparin-mimicking ...multilayers were constructed on PVDF membrane with highly promoted endothelialization and antithrombogenic activities. Oxidized CNT (oCNT) was first functionalized with water-soluble chitosan (polycation), then enwrapped with heparin or a typical sulfonated heparin-mimicking polymers (poly(sodium 4-styrenesulfonate-co-sodium methacrylate)) to construct the multilayers. Then, the surface-deposited multilayers were constructed via electrostatic layer-by-layer assembly of the functionalized oCNTs. The scanning electron microscope and atom force microscope images confirmed that the coated multilayers exhibited nanofibrous and porous structure. The live/dead cell staining and cell viability assay results indicated that the coated nanofibrous multilayers had excellent compatibility with endothelial cells. The cell morphology observation further confirmed the promotion ability of surface endothelialization due to the coated heparin/heparin-mimicking multilayers. Further systematical evaluation on blood compatibility revealed that the surface heparin/heparin-mimicking multilayer-coated membranes also had significantly improved blood compatibility including restrained platelet adhesion and activation, prolonged blood clotting times, and inhibited activation of coagulation and complement factors. In summary, the proposed nanofibrous multilayers integrated endothelialization and antithrombogenic properties; meanwhile, the heparin-mimicking coating validated comparable performances as heparin coating. Herein, it is expected that the surface coating of nanofibrous multilayers, especially the facilely constructed heparin-mimicking coating, may have great application potential in biomedical fields.
► Citric acid was grafted onto polyurethane, used as the anticoagulant additive. ► A new activated partial thromboplastin time method was introduced in this paper. ► The blood compatibility and ...cytocompatibility of the blended membrane were researched.
Citric acid, a widely used anticoagulant, was grafted onto polyurethane through a two-step solution polymerization. The novel synthesized polymer can be directly blended with polyethersulfone (PES) to prepare membranes. The modified membranes showed lower protein (bovine serum albumin, BSA; bovine serum fibrinogen, BFG) adsorption and suppressed platelet adhesion. Due to the binding of calcium ions in blood, the modified membranes effectively prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), plasma recalcification time (PRT) and the whole blood clotting time (WBCT). Furthermore, the modified membranes showed good cytocompatibility, and the surfaces promoted hepatocyte adhesion and proliferation compared to pure PES membrane. These results indicated that the surface modification by blending citric acid grafted polyurethane provided practical application of the membranes with good biocompatibility, especially the anticoagulant property; and the membranes could be used in blood purification fields, such as hemodialysis and bioaritificial liver assist devices.
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