Antibacterial Rate Research Articles

Synergistic Antimicrobial Glycyrrhizic Acid-Based Functional Biosensing Composite for Sensitive Glucose Monitoring and Collaborative Wound Healing.

High glucose blood and bacterial infection remain major issues for the slow healing of diabetic wounds, so developing functional biosensing composite with excellent antibacterial and remarkable glucose response sensitivity is necessary and prospective. Herein, by in situ synthesis AgNPs on the surface of self-prepared PTIGA elastomers, PTIGA-AgNPs conductive composites are obtained with efficient synergistic antibacterial effect, excellent mechanical and self-healing properties. The strain of the composites can reach 1800%, and its self-healing efficiency exceeds 90% at 60°C within 8 h. Both elastomers and composites represent excellent biocompatibility and the antibacterial rate against E. coli and S. aureus exceeded 90%. Moreover, the biosensor assembled from the conductive composites exhibits excellent glucose response sensitivity and stability, with a sensitivity coefficient of 0.518mA mm-1 in the range of 0.2-3.6× 10-3 m glucose concentration, as well as a low detection limit of 0.08× 10-3 m. Furthermore, based on the remarkable antibacterial performance and bioactivity derived from GA, the composites reduce the expression of pro-inflammatory factors and promote the production of anti-inflammatory factors, and effectively promote the regeneration of skin and granulation tissue of wounds in a diabetic full-thickness skin defect model, demonstrating the enormous therapeutic potential in diabetic wound healing.

3D-printed piezocatalytic hydrogels for effective antibacterial treatment of infected wounds

Bacterial-infected wound repair has become a significant public health concern. This study developed a novel 3D-printed piezocatalytic SF-MA/PEGDA/Ag@BT (SPAB) hydrogels were fabricated by using digital light processing. These hydrogels exhibited high consistency, mechanical properties and good biocompatibility. Besides, the SPAB hydrogels exhibited excellent piezocatalytic performance and thus could induce piezoelectric polarization under ultrasound to generate reactive oxygen species (ROS). The SPAB hydrogels possessed an antibacterial rate of 99.23% and 99.96% for Escherichia coli and Staphylococcus aureus, respectively, under 5 min of ultrasonic stimulation (US) in vitro. The US-triggered piezocatalytic performance could increase antibacterial activity and improve the healing process of the infected wound. Therefore, the 3D printed piezocatalytic SPAB hydrogels could be unutilized as wound dressing in the field of bacterial-infected wound repair.

Multihydrogen Bond Modulated Polyzwitterionic Removable Adhesive Hydrogel with Antibacterial and Hemostatic Function for Wound Healing.

Wound management is a major challenge worldwide, placing a huge financial burden on the government of every nation. Wound dressings that can protect wounds, accelerate healing, prevent infection, and avoid secondary damage continue to be a major focus of research in the health care and clinical communities. Herein, a novel zwitterionic polymer (LST) hydrogel incorporated with [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA), mussel-inspired N-[tris(hydroxymethyl)methyl] acrylamide (THMA), and lithium magnesium salt was prepared for functional wound dressings. The incorporation of the THMA monomer containing three hydroxyl groups gives the hydrogel suitable adhesion properties (∼6.0 KPa). This allows the LST zwitterionic hydrogels to bind well to the skin, which not only protects the wound and ensures its therapeutic efficacy but also allows for painless removal and reduced patient pain. Zwitterionic sulfobetaine units of SBMA provide antimicrobial and mechanical properties. The chemical structure and microscopic morphology of LST zwitterionic hydrogels were systematically studied, along with their swelling ratio, adhesion, and mechanical properties. The results showed that the LST zwitterionic hydrogels had a uniform and compact porous structure with the highest swelling and mechanical strain of 1607% and 1068.74%, respectively. The antibacterial rate of LST zwitterionic hydrogels was as high as 99.49%, and the hemostatic effect was about 1.5 times that of the commercial gelatin hemostatic sponges group. In further studies, a full-thickness mouse skin model was selected to evaluate the wound healing performance. Wounds covered by LST zwitterionic hydrogels had a complete epithelial reformation and new connective tissue, and its vascular regenerative capacity was increased to about 2.4 times that of the commercial group, and the wound could completely heal within 12-13 days. This study provides significant advances in the design and construction of multifunctional zwitterionic hydrogel adhesives and wound dressings.

Cellulose nonwoven with fast liquid-discharging and anti-return properties: A microplastic-free surface layer for disposable absorbent hygiene products

Nowadays, the waste of non-biodegradable disposable absorbent hygiene products (DAHPs) has become one of the biggest solid waste in landfills. In this work, the cellulose nonwovens (CNW) were adopted to develop fully biodegradable, microplastic-free surface layer for DAHPs. To achieve this goal, the high hydrophilicity and lack of antibacterial properties were tackled by simultaneously grating tert-butyl isocyanate (TBIS) and anchoring nano zinc oxide (nano-ZnO) on the CNW substrate via a two-step process. The urethane groups formed between cellulose and TBIS strongly coordinates with nano-ZnO, pivotally constructing a cellulose-based surface with moderately-high hydrophobicity with a water contact angle (WCA) of 139.7°, superior antibacterial rates (> 90% against Escherichia coli and Staphylococcus aureus), an excellent air-permeability (2621 mm·s-1) and a good breaking strength (66.9 N·5cm-1). Compared with the commercial sanitary products, the assembled sanitary product with laser-meshed cellulose surface exhibits an even faster liquid discharging ability (< 5 s) and an excellent anti-liquid-return property (> 96%). This innovative, functional cellulose-based fabric holds immense potential for application as sustainable, and microplastic-free surface layer of DAHPs.

Ultrasound-triggerennd piezocatalytic conductive Guar gum/PEDOT: PSS/BTO composite hydrogels for bacterial-infected skin wound healing

Open skin wounds are susceptible to infections by multidrug-resistant bacteria, which can lead to delayed wound healing or worsening of symptoms. Therefore, there is an urgent need to develop a comprehensive strategy that addresses bacterial infections while simultaneously promoting wound healing for optimal clinical outcomes. In this study, we aimed to combine the benefits of antibacterial piezoelectric catalysis action and controlled electrical stimulation to promote skin tissue repair. Initially, piezoelectric catalytic BaTiO3(BTO) nanoparticles were coated with polydopamine (PDA) to improve the interface compatibility between inorganic and organic phase. Subsequently, a novel conductive composite hydrogel termed PPGSCH was synthesized by doping PDA@BTO into poly (3, 4-ethylenedioxythiophene) -poly (styrene sulfonate) (PEDOT: PSS) hydrogel. Traditional dye degradation experiments and EPR tests found that PDA@BTO nanoparticles exhibited superior piezoelectric catalytic efficiency compared with the pristine BTO. Rheological tests and electrical conductivity tests demonstrated better electrical adaptability and mechanical stability of PPGSCH. Remarkably, under the synergism of piezoelectricity and electric polarization induced by ultrasound (US), the antibacterial rate of PPGSCH exceeded 90% in vitro. Furthermore, when subjected to 0.5 W/cm2 US irradiation, it can generate moderate levels of reactive oxygen (ROS) and micro current, promoting the proliferation and migration of mouse fibroblasts. Animal experiments on infected skin wounds in mice showed that PPGSCH could reduce inflammation, accelerate angiogenesis, and ultimately expedite the infected wound healing. This work opens up new possibilities for enhancing the repair of infected skin wounds.

Photocatalytic Activity and Antibacterial Properties of ZnO/CNTs Composites

Photocatalytic technology is one of the promising technologies for wastewater treatment. Herein, zinc oxide/multi-walled carbon nanotubes (ZnO/CNTs) photocatalyst was successfully prepared by hydrothermal method with combining in-situ synthesis technology. The micro-morphology, crystalline structure, surface chemical elements, and optical properties were characterized by SEM, TEM, XRD, FTIR, UV-Vis, and DRS technologies. The ZnO/CNTs photo-catalyst exhibited enhancement photo activity for degradation of organic pollutants under simulated light irradiation. Specifically, the photo-catalytic activity of the ZnO/CNTs catalysts improved with the rise of CNTs content in the composites. Investigation on the photo-degradation mechanism verified that the presence of CNTs in the catalyst not only optimized the band structure of ZnO semiconductor but also contributed to the transfer of photo-generated electrons and reducing the recombination of electron-hole pairs due to its excellent conductivity. Moreover, the active radical groups such as superoxide radical (O-2), hole (h+), and hydroxyl radical (·OH) played the dominated role for the pollutants degradation under the simulated sunlight irradiation. In addition, ZCT20 catalysts and light irradiation had synergistic effects on antibacterial activity, whose antibacterial rates against E. coli and S. aureus were up to 99.96% and 99.94%, respectively. Investigation on antibacterial mechanisms revealed that the existence of ROS and the continuous release of Zn2+ played an important role for improving the antibacterial activity of the ZCT20 catalyst under the simulated sunlight irradiation.

Antibacterial PVDF Coral-Like Hierarchical Structure Composite Film Fabrication for Self-Cleaning and Radiative Cooling Effect.

Passive radiative cooling (PRC) is a zero-energy-consumption technology that reflects sunlight and radiates heat to cold outer space. In this work, a porous poly(vinylidene fluoride)-poly(methyl methacrylate) (PVDF-PMMA) composite film is fabricated by decorating zinc-imidazolate metal-organic framework (MOF) (ZIF-8) particles obtained by phase inversion. Due to the competent scattering via the coral-like hierarchical structures and the vibration excitations of specific functional groups, the prepared film exhibits good solar reflectance (92.6%) and intermediate infrared emittance (99.1%), with an average sub-ambient cooling of 10.4 °C under a solar radiation intensity of 0.6 AM1.5. Additionally, poly(vinylidene fluoride) has a low surface energy, while the ZIF-8 particles and coral-like hierarchical structures enhance the surface roughness, endowing the surface with significant superhydrophobicity characterized by a water contact angle (WCA) of 157.5° and a sliding angle (SA) of 2°. These films exhibit excellent antibacterial properties. When the content of ZIF-8 particles in the film is 300 mg·L-1, the antibacterial rate reaches 100% after 1 h of treatment. Thus, the ZIF-8 porous poly(vinylidene fluoride)-poly(methyl methacrylate) composite (ZPPP) film has potential application prospects in areas with high health and environmental requirements, such as cold chain transportation and public spaces.

Protamine-grafted carboxymethyl chitosan based hydrogel with adhesive and long-term antibacterial properties for hemostasis and skin wound healing

In this study, we developed a tissue-adhesive and long-term antibacterial hydrogel consisting of protamine (PRTM) grafted carboxymethyl chitosan (CMC) (PCMC), catechol groups modified CMC (DCMC), and oxidized hyaluronic acid (OHA), named DCMC-OHA-PCMC. According to the antibacterial experiments, the PCMC-treated groups showed obvious and long-lasting inhibition zones against E. coli (and S. aureus), and the corresponding diameters varied from 10.1 mm (and 15.3 mm) on day 1 to 9.8 mm (and 15.3 mm) on day 7. The DCMC-OHA-PCMC hydrogel treated groups also exhibited durable antibacterial ability against E. coli (and S. aureus), and the antibacterial rates changed from 99.3 ± 0.21 % (and 99.6 ± 0.36 %) on day 1 to 76.2 ± 1.74 % (and 84.2 ± 1.11 %) on day 5. Apart from good mechanical and tissue adhesion properties, the hydrogel had excellent hemostatic ability mainly because of the grafted positive-charged PRTM. As the animal assay results showed, the hydrogel was conducive to promoting the deposition of new collagen (0.84 ± 0.03), the regeneration of epidermis (98.91 ± 6.99 μm) and wound closure in the process of wound repairing. In conclusion, the presented outcomes underline the prospective potential of the multifunctional CMC-based hydrogel for applications in wound dressings.

Preparation and antibacterial mechanism of copper-based silica nanocomposite materials

In this study, copper-based silica nanocomposite with antibacterial properties is prepared by the impregnation adsorption method, employing nano-silica microspheres as carriers. The as-synthesized material has good dispersion and uniform particle size. Copper is loaded on the carrier surface in the form of CuO and Cu(OH)2.and the loading can reach up to 7 %. When the material dosage is 0.001 g·mL-1, the antibacterial rate against E. coli can reach 99 %. Adding rare earth elements improves the materials' physical, chemical, and antibacterial properties. Adding rare trace earth reduces the agglomeration, enhances the specific surface area, affects the existing form of copper, increases the crystallinity, and thus improves the antibacterial activity. The antibacterial properties are improved when the dysprosium concentration is 1 × 10-5 mol·L-1. Copper-based antibacterial nanomaterials mainly destroy the cell membrane and affect the normal function of bacterial proteins via contact antibacterial and antibacterial dissolution routes, hindering their reproduction and killing them. The material exhibits a good application prospect in antibacterial silicone rubber production.·

Preparation of novel zwitterionic polysulfone ultrafiltration membranes for the dual-enhanced antifouling and antibacterial properties by in-situ one pot crosslinking reaction

Zwitterionic polysulfone (PSf) ultrafiltration membranes were fabricated by non-solvent phase separation (NIPS) method. Herein, a casting solution at 45 °C was developed by using chloromethylated polysulfone (CMPSf), N, N-dimethylacetamide (DMAc) as a solvent, 4-amino-benzenesulfonic acid monosodium salt (ABS) as a cross-linking agent, and Na2CO3 as an acid binder. Simultaneously, the occurrence of the electrophilic substitution reaction between ABS and CMPSf caused the formation of ABS grafting CMPSf (CMPSf-g-ABS). After a specific reaction time, the casting solution was applied to cast membranes, which were subsequently submerged in coagulation bath. A zwitterionic ultrafiltration (ZUF) membrane was obtained using NIPS following the treatment of hydrochloric acid (HCl) solution (1 M mol). Because of the formation of cross-linked CMPSf-g-ABS, the results revealed that the casting solution's viscosity increased sharply from 425.4 mPa s at the initial stage (0 h) to 4810.8 mPa s (22 h). Interestingly, the morphology of the membranes with an asymmetric finger-like structure at 0 h gradually transformed to a gradient sponge-like structure after 22 h. Specifically, the ZUF membrane (M22-H) with the gel fraction of 72.1% procured after the reaction of 22 h demonstrated a low water contact angle (40.17°) and a high pure water permeance (420.4 L m−2 h−1 bar−1). The M22-H also exhibited a high flux recovery rate (FRR) (90.2%), bovine serum albumin (BSA) rejection (>95%), and Escherichia coli (E. coli) antibacterial rate (96.2%). The surface of the ZUF membrane with numerous zwitterionic groups enhances the hydration layer's energy (i region <16 nm) and creates a thick hydration layer (ii region >16 nm), causing a significant improvement in the antifouling performance. This research opens new avenues for preparing zwitterionic functional membranes.

In Situ Electrochemical Synthesis of Squamous-like Cu2S Induced by Sulfate-Reducing Bacteria as a Fenton-like Catalyst in Wastewater Treatment: Catalytic Performance and Mechanism.

In this paper, a novel method was proposed for the synthesis of Cu2S on copper mesh via electrolysis in SRB culture medium. It was found that following electrolysis in SRB medium, squamous-like Cu2S arrays were obtained on the copper mesh, and the Cu2S loading contents varied with the electrolyzing parameters. The resultant Cu2S on copper mesh in SRB (CSCM-SRB) with the highest catalytic MB degradation properties was produced by electrolysis at 3.75 mA/cm2 for 900 s. The optimized MB-degrading conditions were determined to be 1.2 cm2/mL CSCM-SRB with 0.05 M H2O2 at 35 °C when pH = 6, under which the degradation of MB reached over 99% after 120 min of reaction. Disinfecting properties was also proven by antibacterial tests, revealing that an almost 100% antibacterial rate against E. coli was obtained after 8 min. The organic compounds produced by SRB adsorbed on CSCM-SRB strongly promoted the degradation of MB. Furthermore, possible Fenton-like mechanisms of CSCM-SRB were proposed, illustrating that ·O2-, ·OH, and 1O2 acted as the main functional species during Fenton-like reactions, leading to effective MB degradation and high antibacterial properties. Finally, a simple device for wastewater treatment was designed, providing possible applications in real environments.

Fast-polymerized lubricant and antibacterial hydrogel coatings for medical catheters

Medical catheters are highly susceptible to friction and infection when intervening or implanting in the body, and to thrombosis when in contact with blood. Coating medical catheters with lubricant and antibacterial hydrogel is an effective strategy but struggle to achieve. Here, hydrogel coating on the catheter surface with lubrication and antibacterial properties was constructed by the rapid polymerization of acrylamide (AAM) and sulfobetaine methacrylate (SBMA) in the presence of quaternary ammonium chitosan (QCS) based on the redox-based cross-linking method. First, the medical catheter surface was decorated with a polyethyleneimine (PEI) adhesive layer. The pre-gel solution was then applied to the catheter surface, followed by immersion in an aqueous FeSO4·7H2O solution, where a large amount of SO4-• was generated by a redox reaction between ammonium persulfate (APS) and Fe2+, which rapidly triggered the monomer to cross-link to form the coating. Polyelectrolyte PEI as the adhesive layer could bind the coating to the substrate through hydrogen bonding interactions and confer antimicrobial properties to the coating with the assistance of QCS (antibacterial rate of 95.88 % against E. coli and 97.11 % against B. subtilis). The hydrogel coatings exhibited outstanding lubricity with a low coefficient of friction (COF ≈ 0.053) and excellent antifouling properties (resists non-specific protein adsorption, inhibits platelet adhesion and prevents thrombosis (The clotting time was extended from 25.6 s to 74.7 s)) based on the integration of SBMA. This work shed new light on the design of hydrogel coatings to achieve modification of the substrate surface.

Structural design and antibacterial properties of porous SiO2/ZnO/Cu2O composites

In this study, the main antibacterial agent employed was nano-ZnO/Cu2O composite powder. The nano-ZnO/Cu2O composite powder was thoroughly dispersed within the gel precursor and subsequently utilized as a carrier for the preparation of porous SiO2 via sol–gel method. Finally, porous SiO2/ZnO/Cu2O composites were obtained. Through the characterization of the phase and structure of the composites, it can be found that nano-ZnO/Cu2O is physically embedded in the porous SiO2 skeleton and fully combined with the porous SiO2. Finally, porous SiO2/ZnO/Cu2O composites were successfully synthesized. The phase and structure of the composites were thoroughly characterized, revealing that nano-ZnO/Cu2O was physically embedded within the porous SiO2 framework and exhibits excellent integration with the porous SiO2 matrix. Compared to single-component nano-ZnO/Cu2O, the composite exhibits significantly enhanced specific surface area and improved pore properties, thereby leading to an enhancement in photocatalytic performance. Furthermore, the antibacterial performance test of the composites clearly demonstrates a remarkable 100% antibacterial rate. Porous SiO2/ZnO/Cu2O composites offer a novel avenue for enhancing the antibacterial properties of ZnO and Cu2O.

Study on PTFE superhydrophobic coating modified by IC@dMSNs and its enhanced antibacterial effect

IntroductionVascular catheter-related infections and thrombosis are common and may lead to serious complications after catheterization. Reducing the incidence of such infections has become a significant challenge. ObjectivesThis study aims to develop a super hydrophobic nanocomposite drug-loaded vascular catheter that can effectively resist bacterial infections and blood coagulation. MethodsIn this study, a SiO2 nanocoated PTFE (Polytetrafluoroethylene) catheter (PTFE-SiO2) was prepared and further optimized to prepare a SiO2 nanocoated PTFE catheter loaded with imipenem/cilastatin sodium (PTFE-IC@dMSNs). The catheters were characterized for performance, cell compatibility, anticoagulant performance, in vitro and in vivo antibacterial effect and biological safety. ResultsPTFE-IC@dMSNs catheter has efficient drug loading performance and drug release rate and has good cell compatibility and anticoagulant effect in vitro. Compared with the PTFE-SiO2 catheter, the inhibition ring of the PTFE-IC@dMSNs catheter against Escherichia coli increased from 3.98 mm2 to 4.56 mm2, and the antibacterial rate increased from about 50.8 % to 56.9 %, with a significant difference (p < 0.05). The antibacterial zone against Staphylococcus aureus increased from 8.63 mm2 to 11.74 mm2, and the antibacterial rate increased from approximately 83.5 % to 89.3 %, showing a significant difference (p < 0.05). PTFE-IC@dMSNs catheter also has good biocompatibility in vivo. Furthermore, the PTFE-IC@dMSNs catheter can reduce the adhesion of blood cells and have excellent anticoagulant properties, and even maintain these properties even with the addition of imipenem/cilastatin sodium. ConclusionCompared with PTFE, PTFE-SiO2 and PTFE-IC@dMSNs catheters have good characterization performance, cell compatibility, and anticoagulant properties. PTFE SiO2 and PTFE-IC@dMSNs catheters have good antibacterial performance and tissue safety against E. coli and S. aureus. Relatively, PTFE-SiO2 and PTFE-IC@dMSNs catheter has better antibacterial properties and histocompatibility and has potential application prospects in anti-bacterial catheter development and anticoagulation.

In vitro degradation and dual responsively antibacterial zeolitic imidazolate frameworks-8@Rhein composite coating on magnesium alloy

Magnesium alloys attract wide attention as bone implant materials due to their outstanding biodegradable and biocompatible properties. However, its rapid degradation rate and bacterial infections after implanting limit its applications. Herein, a self-sacrificing Mg(OH)2 coating was formed on the MAO coated samples to avoid the dissolution of the MAO coating, promoting the in-situ growth of zeolitic imidazolate frameworks-8@Rhein coating on the MAO coated AZ31 alloys (defined as MAO/ZIF-8@Rhein coating). Results displayed that the MAO/ZIF-8@Rhein coating provides favorable corrosion resistance due to the physical barriers of ZIF-8@Rhein NPs and inner MAO coating. Rhein is one-step loaded by ZIF-8 NPs and released in response to both pH changes and near-infrared light (NIR) irradiation to kill bacteria. Additionally, the antibacterial rate of MAO/ZIF-8@Rhein coating reaches to 99.95 % (E. coli) and 99.90 % (S. aureus) under the synergy of contact-killing of Rhein and its photothermal effect by irradiation of 808 nm NIR light, and the photothermal conversion efficiency comes up to 53.4 %. Therefore, this dual responsively antibacterial composite coating with good corrosion resistance will promote the applications of Mg alloys in the biomedical field.

Sputtering-Deposited Ultra-Thin Ag-Cu Films on Non-Woven Fabrics for Face Masks with Antimicrobial Function and Breath NOx Response.

The multifunctional development in the field of face masks and the growing demand for scalable manufacturing have become increasingly prominent. In this study, we utilized high-vacuum magnetron sputtering technology to deposit a 5 nm ultra-thin Ag-Cu film on non-woven fabric and fabricated ultra-thin Ag-Cu film face masks. The antibacterial rates against Escherichia coli and Staphylococcus aureus were 99.996% and 99.978%, respectively, while the antiviral activity against influenza A virus H1N1 was 99.02%. Furthermore, the mask's ability to monitor respiratory system diseases was achieved through color change (from brownish-yellow to grey-white). The low cost and scalability potential of ultra-thin silver-copper film masks offer new possibilities for practical applications of multifunctional masks.

Synthesis of inorganic/organic hybrid-shell antibacterial polyurea microcapsules loaded with Ag/TiO2 nanoparticles

Silver/titanium dioxide (Ag/TiO2) nanoparticles, renowned as effective inorganic antibacterial agents with a wide spectrum of activity and minimal resistance induction, encounter challenges when incorporated into organic substrates. This integration often leads to particle aggregation, resulting in a substantial reduction in antibacterial efficacy. This study devised a novel approach involving loading Ag/TiO2 nanoparticles onto polyurea microcapsules (PUMC), forming hybrid-shelled microcapsules (Ag/TiO2-PUMC) using silane coupling agents. The preparation of polyurea microcapsules offers the advantages of rapid synthesis and mild reaction conditions, facilitating industrial-scale production. Additionally, loading Ag/TiO2 nanoparticles onto polyurea microcapsules helps alleviate the aggregation issue, and the organic nature of polyurea microcapsules enhances compatibility with organic substrates. Characterization techniques, including SEM, TEM, FTIR, XRD, UV–visible absorption spectroscopy, EPR and thermogravimetric analysis, were employed to confirm the successful grafting of Ag/TiO2 nanoparticles onto the PUMC. A comparative analysis between the two silane coupling agents, KH550 and KH792, revealed that the dual amino-functional silane coupling agent, KH792, played a pivotal role in chain extension during the microcapsule self-polymerization process. The antibacterial activity of the Ag/TiO2-PUMC was evaluated against Escherichia coli and Staphylococcus aureus. Remarkably, the hybrid-shelled microcapsules exhibited outstanding antibacterial efficacy, achieving a 99.99% antibacterial rate within just 0.5 hours. This performance surpassed unmodified Ag/TiO2 nanoparticles, highlighting the enhanced antibacterial efficacy of the hybrid-shelled microcapsule structure. This study presents a successful synthesis strategy for inorganic/organic hybrid-shelled antibacterial microcapsules and provides valuable insights for refining inorganic antibacterial agents. The demonstrated approach holds substantial promise for advancing the field of organic antibacterial materials.

Highly flexible carbon nitride-polyethylene glycol-cellulose acetate film with photocatalytic antibacterial activity for fruit preservation

Cellulose acetate film, as a biodegradable and biomass-derived material, has great potential applications in food packaging. However, the poor mechanical and antibacterial properties limit its applications. Herein, a highly flexible carbon nitride-polyethylene glycol-cellulose acetate (CN-PEG-CA) film was successfully prepared by combining graphitic carbon nitride (g-C3N4) photocatalyst with cellulose acetate (CA). The g-C3N4 enables the film with antibacterial activity, as a green photocatalyst. PEG softens the rigid polymer CA and crosslinks CA, PEG, and g-C3N4 together by hydrogen bonding, as a flexible crosslinker. X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectrum (FT-IR) characterizations confirmed the successful preparation of the CN-PEG-CA film. The mechanical property tests demonstrated that adding PEG increased the elongation at break of the film by about 4 times. The composite film had high antibacterial activity, and the bactericidal rates on Escherichia coli and Staphylococcus aureus were 99.98 % and 99.89 %, respectively. It effectively extended the shelf life of strawberries to 96 h and effectively maintained the quality of strawberries during storage. After 96 h, the weight loss rate of strawberries packaged with 15 % CN-PEG-CA film was 21.83 %, vitamin C content was 45.47 %, titratable acidity content was 0.89 %, and color, hardness and total soluble solids were well maintained. And biocompatibility test results showed that the film was safe and nontoxic. From the ecological and economic point of view, the highly flexible and biodegradable films with efficient photocatalytic antibacterial activity synthesized in this paper have great potential in the field of food packaging.

Scalable, high-strength, wear-resistant, antibacterial polyethylene micro-nano fiber protective materials

Polyethylene (PE) fibers, known for their exceptional mechanical and protective properties, have found valuable applications in personal protective equipment during the COVID-19 pandemic. However, traditional PE fibers lack inherent antibacterial properties, making them susceptible to microbial contamination and potentially contributing to the secondary transmission of pathogens. Therefore, the development of antibacterial PE fibers holds paramount importance. Here, we successfully develop high-strength, wear-resistant, and antibacterial PE fibers by applying a dip-coating process with polylactic acid (PLA) solutions containing ZnO-Ag nanoparticles onto the surface of PE fibers. These antibacterial PE fibers exhibit an impressive antibacterial rate exceeding 99.9% against common bacteria, a tensile strength of 33.7 MPa, along with outstanding wear resistance, wearing comfort, and washing stability. Furthermore, continuous production of antibacterial PE nonwovens is achieved by combining roll-to-roll and dip-coating processes. Therefore, the excellent properties and industrial-scale production potential of antibacterial PE fibers position them with broad application prospects in the fields of medical protection, biochemical protection, and beyond.

Construction of organophosphate-functionalized α‑zirconium phosphate towards fire-resistant, weather-resistant and antibacterial reinforcement of transparent fireproof coatings applied on wood substrates

To meet the requirements of fire protection and decorative properties of wood, developing transparent fireproof coatings with excellent comprehensive performance is vital. A new category of organophosphate-grafted α‑zirconium phosphate (α-ZrP) was synthesized as functional flame retardant, then in combination with melamine-formaldehyde resin prepared comprehensive transparent fireproof coatings covering fire protection, smoke suppression, anti-bacteria and weatherability. The results show that adding α-ZrP results in an effective improvement of the mechanical properties, fire protection and smoke suppression under the premise of guaranteeing the high transparency of the coatings. In particular, the MZrPPB3 sample containing a 98:2 mass ratio of phosphate ester to modified α-ZrP possesses 55.2 %, 76.2 % and 23.7 % decrement in flame spread rating, smoke density rating and equilibrium backside temperature at 900 s in comparison with MZrPPB0 sample without α-ZrP, respectively, accompanied by superior adhesion classification of 4B rating and pencil hardness of 2H rating. The efficient fire protection performance of α-ZrP-containing coatings attributes success to the high-quality intumescent char formed by the stable crosslinking and aromatic structures, as confirmed by characterization of FTIR and SEM-EDS analyses. Additionally, adding α-ZrP into the coatings confers them extraordinary weatherability rich in appearance integrity and fire protection performance after accelerated aging test. Meantime, the obtained satisfactory antibacterial property of coatings relates to the presence of α-ZrP with an antibacterial rate of up to 99.0 % for MZrPPB3 against Escherichia coli.