Tribovoltaic Effect Strengthened Microwave Catalytic Antibacterial Composite Hydrogel.

Microwave (MW) therapy is an emerging therapy with high efficiency and deep penetration to combat the crisis of bacterial resistance. However, as the energy of MW is too low to induce electron transition, the mechanism of MW catalytic effect remains ambiguous. Herein, a cerium-based metal-organic framework (MOF) is fabricated and used in MW therapy. The MW-catalytic performance of CeTCPP is largely dependent on the ions in the liquid environment, and the electron transition is achieved through a "tribovoltaic effect" between water molecules and CeTCPP. By this way, CeTCPP can generate reactive oxygen species (ROS) in saline under pulsed MW irradiation, showing 99.9995 ± 0.0002% antibacterial ratio against Staphylococcus aureus (S. aureus) upon two cycles of MW irradiation. Bacterial metabolomics further demonstrates that the diffusion of ROS into bacteria led to the bacterial metabolic disorders. The bacteria are finally killed due to "amino acid starvation". In order to improve the applicability of CeTCPP, It is incorporated into alginate-based hydrogel, which maintains good MW catalytic antibacterial efficiency and also good biocompatibility. Therefore, this work provides a comprehensive instruction of using CeTCPP in MW therapy, from mechanism to application. This work also provides new perspectives for the design of antibacterial composite hydrogel.

Photocatalysis Meets Piezoelectricity in a Type-I Oxygen Vacancy-Rich BaTiO3/BiOBr Heterojunction: Mechanism Insights from Characterizations to DFT Calculations.

It is a challenging task to design a piezoelectric photocatalyst with excellent performance under mechanical agitation instead of ultrasonic irradiation. Integrating vacancy defects into a heterojunction seems to be an effective strategy for synergistically increasing its piezo-photocatalytic performance. For this goal, a two-step hydrothermal method was adopted to architect a type-I oxygen-vacancy-rich BaTiO3/BiOBr heterojunction to surge the degradation of Rhodamine B (RhB) under the combined action of simulated sunlight irradiation and mechanical agitation. Various instrumental techniques demonstrated the formation of a BaTiO3/BiOBr heterojunction with high crystallinity. The existence of surface oxygen vacancies was confirmed by XPS and EPR tests. PFM results manifested that this heterojunction had excellent piezoelectric properties, with a piezoelectric response value of 30.31 pm V-1. Comparative experiments indicated that RhB degradation efficiency under piezo-photocatalysis over this heterojunction largely exceeded the total sum of those under piezocatalysis and photocatalysis. h+, ·O2-, and 1O2 were the dominant reactive species for RhB degradation. The improved separation efficiency of photogenerated charges was verified by electrochemical measurements. DFT calculations indicated that the polarization of BaTiO3 could affect the electronic band structure of BiOBr. This work will provide comprehensive insights into piezo-photocatalytic mechanism at a microcosmic level and help to develop new-styled piezoelectric photocatalysts.

Natural Extracts for Antibacterial Applications.

Bacteria-induced epidemics and infectious diseases are seriously threatening the health of people around the world. In addition, antibiotic therapy has been inducing increasingly more serious bacterial resistance, which makes it urgent to develop new treatment strategies to combat bacteria, including multidrug-resistant bacteria. Natural extracts displaying antibacterial activity and good biocompatibility have attracted much attention due to greater concerns about the safety of synthetic chemicals and emerging drug resistance. These antibacterial components can be isolated and utilized as antimicrobials, as well as transformed, combined, or wrapped with other substances by using modern assistive technologies to fight bacteria synergistically. This review summarizes recent advances in natural extracts from three kinds of sources-plants, animals, and microorganisms-for antibacterial applications. This work discusses the corresponding antibacterial mechanisms and the future development of natural extracts in antibacterial fields.

A Smart Bacteria-Capture-Killing Vector for Effectively Treating Osteomyelitis Through Synergy Under Microwave Therapy.

Osteomyelitis caused by deep tissue infections is difficult to cure through phototherapy due to the poor penetration depth of the light. Herein, Cu/C/Fe3O4-COOH nanorod composites (Cu/C/Fe3O4-COOH) with nanoscale tip convex structures are successfully fabricated as a microwave-responsive smart bacteria-capture-killing vector. Cu/C/Fe3O4-COOH exhibited excellent magnetic targeting and bacteria-capturing ability due to its magnetism and high selectivity affinity to the amino groups on the surface of Staphylococcus aureus (S. aureus). Under microwave irradiation, Cu/C/Fe3O4-COOH efficiently treated S. aureus-infected osteomyelitis through the synergistic effects of microwave thermal therapy, microwave dynamic therapy, and copper ion therapy. It is calculated the electric field intensity in various regions of Cu/C/Fe3O4-COOH under microwave irradiation, demonstrating that it obtained the highest electric field intensity on the surface of copper nanoparticles of Cu/C/Fe3O4-COOH due to its high-curvature tips and metallic properties. This led to copper nanoparticles attracted more charged particles compared with other areas in Cu/C/Fe3O4-COOH. These charges are easier to escape from the high curvature surface of Cu/C/Fe3O4-COOH, and captured by adsorbed oxygen, resulting in the generation of reactive oxygen species. The Cu/C/Fe3O4-COOH designed in this study is expected to provide insight into the treatment of deep tissue infections under the irradiation of microwave.

Interfacial and Defect Polarization Enhanced Microwave Noninvasive Therapy for Staphylococcus aureus-Infected Chronic Osteomyelitis.

Chronic osteomyelitis (COM), is a long-term, constant, and intractable disease mostly induced by infection from the invasion of Staphylococcus aureus (S. aureus) into bone cells. Here, we describe a highly effective microwave (MW) therapeutic strategy for S. aureus-induced COM based on the in situ growth of interfacial oxygen vacancy-rich molybdenum disulfide (MoS2)/titanium carbide (Ti3C2Tx) MXene with oxygen-deficient titanium dioxide (TiO2-x) on Ti3C2Tx (labeled as HU-MoS2/Ti3C2Tx) by producing reactive oxygen species (ROS) and heat. HU-MoS2/Ti3C2Tx produced heat and ROS, which could effectively treat S. aureus-induced COM under MW irradiation. The underlying mechanism determined by density functional theory (DFT) and MW vector network analysis was that HU-MoS2/Ti3C2Tx formed a high-energy local electric field under MW irradiation, consequently generating more high-energy free electrons to pass and move across the interface at a high speed and accelerate by the heterointerface, which enhanced the charge accumulation on both sides of the interface. Moreover, these charges were captured by the oxygen species adsorbed at the HU-MoS2/Ti3C2Tx interface to produce ROS. MoS2 facilitated multiple reflections and scattering of electromagnetic waves as well as enhanced impedance matching. Ti3C2Tx enhanced the conduction loss of electromagnetic waves, while functional groups induced dipole polarization to enhance attenuation of MW.

Microwave-excited, antibacterial core-shell BaSO4/BaTi5O11@PPy heterostructures for rapid treatment of S. aureus-infected osteomyelitis.

Owing to its deep penetration capability, microwave (MW) therapy has emerged as a promising method to eradicate deep-seated acute bone infection diseases such as osteomyelitis. However, the MW thermal effect still needs to be enhanced to achieve rapid and efficient treatment of deep focal infected areas. In this work, the multi-interfacial core-shell structure barium sulfate/barium polytitanates@polypyrrole (BaSO4/BaTi5O11@PPy) was prepared, which exhibited enhanced MW thermal response via the well-designed multi-interfacial structure. To be specific, BaSO4/BaTi5O11@PPy achieved rapid temperature increases in a short period and efficient clearance of Staphylococcus aureus (S. aureus) infections under MW irradiation. After 15 min MW irradiation, the antibacterial efficacy of BaSO4/BaTi5O11@PPy can reach up to 99.61 ± 0.22%. Their desirable thermal production capabilities originated from enhanced dielectric loss including multiple interfacial polarization and conductivity loss. Additionally, in vitro analysis illuminated that the underlying antimicrobial mechanism was attributed to the noticeable MW thermal effect and changes in energy metabolic pathways on bacterial membrane instigated by BaSO4/BaTi5O11@PPy under MW irradiation. Considering remarkable antibacterial efficiency and acceptable biosafety, we envision that it has significant value in broadening the pool of desirable candidates to fight against S. aureus-infected osteomyelitis. STATEMENT OF SIGNIFICANCE: The treatment of deep bacterial infection remains challenging due to the ineffectiveness of antibiotic treatment and the susceptibility to bacterial resistance. Microwave (MW) thermal therapy (MTT) is a promising approach with remarkable penetration to centrally heat up the infected area. This study proposes to utilize the core-shell structure BaSO4/BaTi5O11@PPy as an MW absorber to achieve localized heating under MW radiation for MTT. In vitro experiments demonstrated that the disrupted bacterial membrane is primarily due to the localized high temperature and interrupted electron transfer chain. As a consequence, its antibacterial rate is as high as 99.61% under MW irradiation. It is shown that the BaSO4/BaTi5O11@PPy is a promising candidate for eliminating bacterial infection in deep-seated tissues.

Magnetic Composite Rapidly Treats Staphylococcus aureus-Infected Osteomyelitis through Microwave Strengthened Thermal Effects and Reactive Oxygen Species.

It is difficult to effectively treat bacterial osteomyelitis using photothermal therapy or photodynamic therapy due to poor penetration of light. Here, a microwave (MW)-excited magnetic composite of molybdenum disulfide (MoS2 ) / iron oxide (Fe3 O4 ) is reported for the treatment of bacteria-infected osteomyelitis. In in vitro and in vivo experiments, MoS2 /Fe3 O4 is shown to effectively eradicate bacteria-infected mouse tibia osteomyelitis, due to MW thermal enhancement and reactive oxygen species (ROS) (1 O2 and ·O2 - ) production under MW radiation. In addition, the mechanism of MW heat generation is proposed by MW network vector analysis. By the density functional theory and finite element method, the ROS generation mechanism is proposed. The synergy or conductive network between dielectric MoS2 and magnetic Fe3 O4 can reach both enhancement of the dielectric and magnetic attenuation capability. In addition, abundant interfaces are generated to enhance the attenuation of electromagnetic waves by MoS2 and Fe3 O4, introducing multiple reflections and interfacial polarization. Therefore, MoS2 /Fe3 O4 has excellent MW absorption ability based on the synergy or conductive network between MoS2 and magnetic Fe3 O4 as well as multiple dielectric reflections and interfacial polarization.

Gallium (Ga)-strontium (Sr) layered double hydroxide composite coating on titanium substrates for enhanced osteogenic and antibacterial abilities.

Bacterial infection and poor osteogenic capacity can result in the loosing or failure of titanium (Ti)-based implants in the clinic. Therefore, it is urgent to design an effective approach to enhance the osteogenic property and restrict bacterial activity. In this study, a layered double hydroxide (LDH) composed of Ga and Sr ions on Ti substrates by a hydrothermal method, then calcined in 250°C and denoted as LDH250. The scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were confirmed that the LDH films were successfully formed on the Ti substrates. Importantly, the obtained LDH films can induce an alkaline microenvironment around the Ti surface and regulate the behaviors of osteogenic cells and bacteria. In vitro cellular experiments, the LDH250 can enhance the differentiation of both MC3T3-E1 cells and osteoblasts, stimulate alkaline phosphatase activity (ALP), collagen secretion, and mineralization levels. Meanwhile, antimicrobial assay against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) demonstrated that the LDH250 samples had strong antibacterial abilities, which attributed to the release profile of Ga3+ could act as a "Trojan horse" to destroy the bacterial iron metabolism, inducing of local alkaline environment, and producing reactive oxygen species. Hence, this study provides an effective method for reducing antibacterial infection and enhancing the bone integrative capacity of Ti-based implants for orthopedic applications.

A versatile and low-toxicity material for photothermal therapy in deeper tissues.

The limited depth of the near infrared (NIR) response is one of the major flaws of the present photothermal therapy (PTT). In this article, thermosensitive polyurethane urea (TPUU) was synthesized by polymerization. Subsequent experiments showed that, compared with classical photosensitizers, TPUU has higher photothermal effects and lower cytotoxicity. These valuable properties could make the present PTT research provide more therapeutic options among different tissues and organs. As a practical example, TPUU was applied to regulate the intestinal flora through external NIR irradiation, which implied its promising expanded applications in deeper tissues.

ZnO/CPAN Modified Contact Lens with Antibacterial and Harmful Light Reduction Capabilities.

Compared with traditional glasses, the comfortable and convenient contact lens (CL) has seen an upsurge among the public. However, due to the lack of antibacterial properties of ordinary CLs, the risk of eye infection is greatly increased accordingly. On the other hand, ordinary CLs also cannot effectively reduce the short-wavelength blue light emitted from electronic products, such as mobile phones and computers. Aiming at the above two problems, zinc oxide (ZnO)/cyclized polyacrylonitrile (CPAN) composites are developed for CL modification. After loading with ZnO/CPAN (ZC), the CL shows a broad-spectrum antibacterial property. Further experiments also prove that it can block UVB, UVA, as well as blue light selectively, under the premise of ensuring hydrophilicity and certain transparency. Theoretically, this ZC-decorated CL can fundamentally reduce the damage to the eyes from harmful light emitted by light-emitting diodes and the secretion of pro-inflammatory factors, which is thus a promising eye protection strategy for modern society.

Dual-Effective Chronic Wounds Management System through a Monoglyceride Binary Blend Matrix Based Thermal-Responsive Phase-Transition Substrate.

A new monoglyceride-based heat-sensitive substrate is proposed, for the first time, as a wound management system. First, an appropriate portion of glyceryl monooleate (GMO) and glyceryl monostearate (GMS) is mixed to provide a thermal phase responsive matrix (GMO-GMS, GG). Subsequently, to improve the photothermal responsive and antibacterial performance, silver nanoparticles (Ag) decorated reduced graphene oxide (rGO) nanocomposite (rGO-Ag) is added to the GG matrix to obtain (GG-rGO-Ag). According to the systematic studies from uninfected, infected, and diabetic wound models, by applying near infrared (NIR) laser, the phase change of GG-rGO-Ag can be triggered to release Ag on demand for sterilization. More importantly, this smart GG substrate can also promote the production of vascular endothelial growth factor protein, thus serving as a NIR defined mufti-effective wound management system.

A multi-effective and long-acting immunotherapy through one single hydrogel based injection.

A dual-effective (photothermal and immune) therapy employing gold nanorods (AuNRs) with a drug (two macrophage migration inhibitory factor (MIF) inhibitors) sustained release hydrogel was designed in this paper. The subsequent cellular and animal studies demonstrated that the proposed therapy can not only inhibit the proliferation, migration, and recurrence of cancer cells, but also improve the immune function (increase the infiltration of CD8+ killer T cells in tumors) without the traditional multiple injections of expensive immune drugs.

Fast-Acting Black-Phosphorus-Assisted Depression Therapy with Low Toxicity.

A black phosphorus (BP)-nanosheet-based drug-delivery system containing a therapeutic drug (Fluoxetine, Flu) is synthesized. According to subsequent behavioral, biochemical, and electrophysiological analysis, BP-Flu, after irradiated with near-infrared light (808 nm), can significantly reduce the therapy time of depression. Meanwhile, the inherent biotoxicity of Flu is also alleviated.

Synergic Effect between Adsorption and Photocatalysis of Metal-Free g-C3N4 Derived from Different Precursors.

Graphitic carbon nitride (g-C3N4) used in this work was obtained by heating dicyandiamide and melamine, respectively, at different temperatures. The differences of g-C3N4 derived from different precursors in phase composition, functional group, surface morphology, microstructure, surface property, band gap and specific surface area were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-visible diffuse reflection spectroscopy and BET surface area analyzer, respectively. The photocatalytic discoloration of an active cationic dye, Methylene Blue (MB) under visible-light irradiation indicated that g-C3N4 derived from melamine at 500°C (CN-M500) had higher adsorption capacity and better photocatalytic activity than that from dicyandiamide at 500°C (CN-D500), which was attributed to the larger surface area of CN-M500. MB discoloration ratio over CN-M500 was affected by initial MB concentration and photocatalyst dosage. After 120 min reaction time, the blue color of MB solution disappeared completely. Subsequently, based on the measurement of the surface Zeta potentials of CN-M500 at different pHs, an active anionic dye, Methyl Orange (MO) was selected as the contrastive target pollutant with MB to reveal the synergic effect between adsorption and photocatalysis. Finally, the photocatalytic mechanism was discussed.

Dye-sensitized solar cell based on blood mimetic thixotropy sol-gel electrolyte.

Blood mimetic thixotropy sol-gel electrolytes were prepared and sandwiched between dye-coated porous TiO(2) and a platinum counter-electrode to form a dye-sensitized solar cell. The highest overall conversion efficiency of 6.45%, and the fill factor of 0.74 under the white light irradiation AM 1.5 (100 mW cm(-2)) were obtained.

[Operative treatment of complicated distal femoral fractures].

OBJECTIVE: To explore an effective way for treating severe complicated distal femoral fractures. METHODS: Twenty-six patients with complicated distal femoral fracture who all belonged to 33C3.3 type according to AO/ASIF classification, were treated with a lateral condylar buttress plate or self-designed aliform anatomical plate, and operated on with allogeneic bone grafting. RESULTS: All cases were followed up for an average of 14 months (ranging 5-25 months). Twenty-four wounds were primary healing postoperatively, 2 wounds were infected and healed after dressing change. Twenty-four had bone healing after 4-11 months, 2 needed to operate again because of earlier weight-bearing resulting in fixation failure. According to shelbourne and Brueckmann score, the excellent and good rate was 88.46%. CONCLUSION: The internal fixation for complicated distal femoral fracture by self-designed aliform anatomical plate and lateral condylar buttress plate with a great deal of allograft bone is an effective surgical method. As it has long oval holes and the holes are consecutive, the aliform anatomical plate is more suitable for severe complicated fractures. At the same time, autogenous-ilium transplantation can be substituted by the allograft bone.