Excellent Antimicrobial Properties Research Articles

Comparison of Escherichia coli Responses to Different Silver Nanoparticles with Different Particle Sizes and Surface Coatings

AbstractAgNPs are widely used for their excellent antimicrobial properties, whereas the cytotoxicity they possess makes them an unignorable environmental problem. Considering the impact of particle size and surface coating on the antibacterial properties, four types of AgNPs are selected: citrate‐coated 20 nm (C20), polyvinylpyrrolidone‐coated 20 nm (P20), citrate‐coated 100 nm (C100), and polyvinylpyrrolidone‐coated 100 nm (P100) AgNPs. All four AgNPs significantly affect the ribosome pathway, with stronger binding of large and small subunits. 20 nm and 100 nm AgNPs both affected the biosynthesis and metabolism of several amino acids (including arginine, glycine, serine, threonine, glyoxylic acid, and dicarboxylic acid). P20 and C100 exposure affected bacterial chemotaxis and flagellar motility. This study preliminarily explained the response mechanism of E. coli to AgNPs with different properties, which provided a theoretical basis for predicting the response mechanism of E. coli to metal nanoparticles with similar properties.

Silk-fibroin-based nanofibrous scaffolds integrated with nano-engineered living bacteria enabling antibiotic-free accelerated infected wound healing

Bacteria‐infected skin wounds are an immense public health challenge for high mortality-rate and enormous financial burden worldwide. Emerging living bacterial therapy promises the desired therapeutic efficacy for wound healing, however, its indiscriminate negative effects on the bioactivity of beneficial bacteria remain enormous challenges for clinical far-ranging applications. Herein, silk fibroin-based nanofibrous scaffolds equipped with nano-engineered tannic acid (TA)-Fe(III) chelate-encapsulated Lactobacillus reuteri (denoted as Mbr/L@FeTA) were proposed for antibiotic-free accelerated bacteria‐infected wound healing. Mbr/L@FeTA exhibited excellent antimicrobial properties (99.03% and 98.60% bactericidal efficiency against Escherichia coli and Staphylococcus aureus, respectively), gratifying mechanical properties and biocompatibility. Furthermore, due to on-demand TA-Fe(III) chelate-encapsulated bacterial tactics, Mbr/L@FeTA demonstrates exceptional environmental resistance and maintains satisfactory biological-activity even when administered with antibiotics. Additionally, Mbr/L@FeTA enables the stable release of organic acids and other metabolites that significantly improve the wound microenvironment and modulate inflammatory reactions. In vivo and in vitro experiments confirmed that Mbr/L@FeTA strongly promoted cell growth and proliferation, inhibited bacteria growth at the wound-site, and further accelerated the healing process in bacteria-infected wounds. These findings suggest that Mbr/L@FeTA exhibits great potential for applications in antibiotic-free infected wound therapy and simultaneously represents a useful approach for clinical applications of living bacterial therapy.

Polyvinyl alcohol/PEDOT:PSS with Fe3+/amylopectin enabled highly tough, anti-freezing and healable hydrogels for multifunctional wearable sensors

In recent years, hydrogel-based flexible sensors have garnered increasing attention in research. Ionic hydrogels, enriched with large amounts of ionic liquids, exhibit electrical conductivity, excellent electrochemical stability, anti-freezing, and antimicrobial properties. However, most ionic hydrogels suffer from poor mechanical properties, limiting their adaptability to more complex application scenarios. Integrating conductive polymers into hydrogels leads to desirable features such as increased specific surface area, soft and biocompatible interfaces, and high electrolyte permeability. In this study, we successfully prepared Fe3+/Ap@PVA/PEDOT double-network hydrogel. Utilizing polyvinyl alcohol (PVA) as the primary matrix, we introduced PEDOT:PSS and FeCl3 to confer conductivity to the hydrogel. The incorporation of amylopectin (Ap) further enhanced mechanical performance. The resulted hydrogel sensor exhibits outstanding mechanical properties, allowing for stretching up to 347 % and withstanding a tensile force of 505 kPa. In addition, it exhibits excellent antifreeze properties (can work at −30 °C), healability, water retention, and high sensitivity to stretching (GF = 4.72 at a 200 % strain ratio), compression (GF = 2.97 at a 12 % compressive ratio), and temperature (TCR = 2.46). These remarkable properties of the hydrogel make it possible in applications such as human motion monitoring, handwriting recognition, and temperature sensing.

Vancomycin-Loaded Sol-Gel System for In Situ Coating of Artificial Bone to Prevent Surgical Site Infections.

Surgical site infections (SSIs) related to implants have always been a major challenge for clinical doctors and patients. Clinically, doctors may directly apply antibiotics into the wound to prevent SSIs. However, this strategy is strongly associated with experience of doctors on the amount and the location of antibiotics. Herein, an in situ constructable sol-gel system is developed containing antibiotics during surgical process and validated the efficacy against SSIs in beagles. The system involves chitosan (CS), β-glycerophosphate (β-GP) and vancomycin (VAN), which can be adsorbed onto porous hydroxyapatite (HA) and form VAN-CS/β-GP@HA hydrogel in a short time. The VAN concentration from VAN-CS/β-GP@HA hydrogel is higher than minimum inhibitory concentration (MIC) against Staphylococcus aureus (S. aureus) at the 21st day in vitro. In an in vivo canine model for the prevention of SSIs in the femoral condyle, VAN-CS/β-GP@HA exhibits excellent biocompatibility, antimicrobial properties, and promotion of bone healing. In all, the CS/β-GP instant sol-gel system is able to in situ encapsulate antibiotics and adhere on artificial bone implants during the surgery, effectively preventing SSIs related to implants.

Multifunctional Nanosystem for Dual Anti-Inflammatory and Antibacterial Photodynamic Therapy in Infectious Diabetic Wounds.

Infectious diabetic wounds present a substantial challenge, characterized by inflammation, infection, and delayed wound healing, leading to elevated morbidity and mortality rates. In this work, we developed a multifunctional lipid nanoemulsion containing quercetin, chlorine e6, and rosemary oil (QCRLNEs) for dual anti-inflammatory and antibacterial photodynamic therapy (APDT) for treating infectious diabetic wounds. The QCRLNEs exhibited spherical morphology with a size of 51 nm with enhanced encapsulation efficiency, skin permeation, and localized delivery at the infected wound site. QCRLNEs with NIR irradiation have shown excellent wound closure and antimicrobial properties in vitro, mitigating the nonselective cytotoxic behavior of PDT. Also, excellent biocompatibility and anti-inflammatory and wound healing responses were observed in zebrafish models. The infected wound healing properties in S. aureus-infected diabetic rat models indicated re-epithelization and collagen deposition with no signs of inflammation. This multifaceted approach using QCRLNEs with NIR irradiation holds great promise for effectively combating oxidative stress and bacterial infections commonly associated with infected diabetic wounds, facilitating enhanced wound healing and improved clinical outcomes.

High performance enrichment and analysis of fluoroquinolones residues in environmental water using cobalt ion mediated paper-based molecularly imprinted polymer chips

BackgroundFluoroquinolones (FQs) are widely used for their excellent antimicrobial properties, yet their release into aquatic environments pose risks to ecosystems and public health. The accurate monitoring and analysis of FQs present challenges due to their low concentrations and the complex matrices found in actual environmental samples. To address the need for auto-pretreatment and on-line instrumental analysis, developing new microextraction materials and protocols is crucial. Such advancements will provide better analytical assurance for the effective extraction and determination of FQs at trace levels, which is of great significance to environmental protection and human health. ResultsIn this work, we presented a Co2+ mediated paper-based molecularly imprinted polymer chip (CMC@Co-MIP), combined with UPLC analysis, to develop an effective analytical method for identifying and quantifying trace amounts of ciprofloxacin (CIP) and enrofloxacin (ENR) in water samples. Notably, the addition of Co2+ in CMC@Co-MIP helped to capture the template molecule CIP through coordination before imprinting, which significantly improved the ordering of the imprinted cavities. CMC@Co-MIP exhibited a maximum adsorption capacity up to 500.20 mg g−1 with an imprinting factor of 4.12, surpassing previous reports by a significant margin. Furthermore, the enrichment mechanism was extensively analyzed by various characterization techniques. The developed method showed excellent repeatability and reproducibility (RSD<13.0%) with detection limits ranging from 0.15 to 0.21 μg L−1 and recoveries ranging from 64.9% to 102.3% in real spiked water samples. SignificanceWe developed a novel microextraction paper-based chip based on Co2+ mediation, which effectively improved the selectivity and convenience of extracting FQs. This breakthrough allowed the chip to have a high enrichment efficiency as well as provide a robust on-line instrumental program. It also confirms that the imprinting scheme based on metal ion coordination is a high-performance strategy.

Microstructural, mechanical, thermo‐rheological, barrier, and antimicrobial properties of coextruded tri‐layer polylactide/encapsulated geraniol/polylactide‐graphene nanoplatelets films

AbstractA sustainable polylactide (PLA)‐based multilayer food packaging film was developed to improve neat PLA films' modest mechanical, thermal, and water/gas barrier properties. To improve the desired properties and impart antimicrobial aspects to the composite films, graphene nanoplatelets (GNP), and geraniol (GER) were reinforced into single‐layered PLA films. The project aimed to assemble three monolayers into multilayer films (MLF) through a coextrusion process, keeping the PLA‐GER layer in the core. X‐ray diffractograms, micrographs, and roughness parameters of the films demonstrated the dispersion of GNP in the film. Thermogravimetric analysis confirmed an enhancement in the thermal stability of the MLF by around 8°C when compared against single‐layer PLA films. An improvement in mechanical rigidity was supported by tensile (&gt;87%) and rheological measurements. The polymers exhibit liquid‐like behavior in melts. Barrier properties did not improve for the MLF due to the agglomeration of GNP. The excellent antimicrobial properties of the MLFs for 3 weeks of storage at refrigerated conditions against both gram‐positive and gram‐negative pathogens were attributed to the release of GER from the film into the packed chicken samples and proved their potential for use in the food industry.

Rosin-based self-healing functionalized composites with two-dimensional polyamide for antimicrobial and anticorrosion coatings

The design of polymer-based composites possessing good mechanical and self-healing properties remains a challenge in the development of high-performance self-healing materials. In this study, we used two-dimensional polyamide (2DPA), biomass rosin ester, and a dynamic crosslinking agent poly (urethane-urea) as raw materials, and prepared biomass rosin-based composites via in situ polymerization. The composites with 1 wt% 2DPA exhibited excellent self-healing properties (self-healing efficiency of 94 % after 24 h at 80 °C) and mechanical properties (tensile strength = 7.8 MPa). Moreover, the composites were applied to anticorrosion and antimicrobial coatings, which possessed excellent anticorrosion and antimicrobial properties. This study provides a new strategy for developing high-performance bio-based self-healing composites.

Synthesis and Characterization of Graphene Nanoparticles for Improved Antimicrobial Performance

Graphene is considered an excellent material for biomedical applications because of its outstanding antimicrobial performance. However, the high synthesis cost and complexity make it difficult to apply this material in numerous fields. This research focuses on synthesizing graphene nanoparticles (NPs) cost-effectively and simply. Cost-effective chemicals were used here for synthesizing graphene NPs. A simple and easy technique has been followed throughout the process. The synthesized graphene NPs were characterized by ultraviolet–visible (UV) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) and antimicrobial analyses. TEM analysis revealed the size and structure of nanosized graphene NPs. Excellent antimicrobial properties 99.99% bacterial inhibition against gram-negative bacterium E. coli have been obtained. The findings indicate the potential applications in different biomedical sectors for their improved antimicrobial properties.

The effect of avian eggshell membrane structure on microbial penetration: A simulation study

Avian eggshells exhibit excellent antimicrobial properties. In this study, we conducted simulation experiments to explore the defense mechanisms of eggshell membranes with regards to their physical features. We developed a mathematical model for the movement of microorganisms and estimated their penetration ratio into eggshell membranes based on several factors, including membrane thickness, microbial size, directional drift, and attachment probability to membrane fibers. These results not only suggest that an eggshell membrane with multiple layers and low porosity indicates high antimicrobial performance, but also imply that the fibrous network structure of the membrane might contribute to effective defense. Our simulation results aligned with experimental findings, specifically in measuring the penetration time of Escherichia coli through the eggshell membrane. We briefly discuss the significance and limitations of this pilot study, as well as the potential for these results, to serve as a foundation for the development of antimicrobial materials.

Preparation of silver nitroprusside nanoparticles for enhanced acid red 94 removal from effluent: A study on synergistic adsorption and photocatalytic processes, with toxicological assessment

Toxic dye pollution in water is an urgent global environmental issue. The synergistic action of adsorption and degradation has shown great removal effects for treating toxic dyes in aqueous environments. Silver ions and nitroprusside salts exhibit excellent antimicrobial, anticancer, and biocompatible properties and are widely used in the pharmaceutical field; however, their application in environmental treatment has not been extensively explored. Hence, we prepared novel and highly efficient silver nitroprusside nanoparticles (Ag2[Fe(CN)5NO] NPs) through a one-pot reaction using sodium nitroprusside and silver nitrate for the first removal of acid red dye (AR 94). Furthermore, Ag2[Fe(CN)5NO] NPs were characterized using various analytical techniques. The Ag2[Fe(CN)5NO] NPs have both cubic and rod-like structures with a size of 107.46 ± 34.54 d.nm, the PDI is 0.263 ± 0.018 and the zeta potential is −46.9 ± 0.026 mV. In addition, the synergistic adsorption and degradation performance of Ag2[Fe(CN)5NO] NPs was evaluated. The removal efficiencies of Ag2[Fe(CN)5NO] NPs on AR 94 can reach more than 95 % under natural light irradiation and optimal reaction conditions of 60 mg/L AR 94 dye concentration, pH 6, temperature 45 °C, and time 6 h. After 5 cycles of recycling, the removal efficiency remained above 90 %. The aqueous solution obtained after removing AR 94 demonstrated no adverse effects on Zea mays L. seed growth. It also exhibited low toxicity to Artemia salina. These results emphasize the potential of Ag2[Fe(CN)5NO] NPs as an efficient and environmentally friendly material for the removal of dyes from aqueous environments.

High-performance lithium metal anode enhanced by multifunctional film of PAN@AgNWs with antimicrobial activity

Lithium metal is expected to be the perfect anode material for the next generation of rechargeable batteries owing to its ultra-high theoretical specific capacity, low density and the lowest redox potential. However, the practical application of lithium metal batteries faces serious challenges, including uneven lithium deposition, negative electrode volume expansion, and short circuits brought by dendritic protrusions. Although the 3D structure of silver nanowires is effective in inhibiting lithium dendrite growth and lithium metal volume expansion, it still suffers from lithium inhomogeneity caused by uneven distribution of silver nanowires and complicated preparation. Therefore, PAN@AgNWs collector was prepared by a simple suction filtration method, and uniform dispersion of silver nanowires and uniform deposition of lithium were achieved. Lithium nucleation overpotential and lithium dendrite formation can be effectively reduced by PAN@AgNWs hosts due to the reduction of local current density by 3D collectors and the improved lithiophilicity of silver nanowires. With low voltage hysteresis, the symmetric battery constructed with its composite anode may cycle steadily for 4500 h at 1 mA cm−2 and 1 mAh cm−2. At the same time, the Li-PAN@AgNWs||LFP full cell still possesses a reversible of 144.18 mAh g−1 after 500 cycles at 1C. Moreover, due to large specific surface area and high surface energy of 3D silver nanowires, it exhibits excellent antimicrobial properties, with an inactivation efficiency of 96.3 % after contacting with E. coli for 2.5 h. This work shows the possibility of using PAN@AgNWs in a large scale for LMBs, and paves the way for development of high-performance antimicrobial materials.

Study of in vitro wear resistance and degradation properties of self-made treated medical magnesium alloys

Study of <i>in vitro</i> wear resistance and degradation properties of self-made treated medical magnesium alloys

Application of graphene nanoparticles in sports clothing for enhancing moisture absorption, breathability, wear resistance, and antimicrobial properties

Carbon nanomaterials, with their exceptional properties, exhibit promising potential in the textile industry. In this study, we prepare sports clothing containing graphene nanoparticles (GNPs) for college physical education (PE) teachers and investigate its performance such as moisture absorption, breathability, wear resistance, and antimicrobial properties. The results showed that the moisture absorption rate and air permeability of the sports clothing containing GNPs were significantly superior (31.3% and 203.5 mm/s respectively) compared to conventional sports clothing. Additionally, our findings demonstrated that the sports clothing containing GNPs has excellent wear-resistance and antimicrobial properties. In conclusion, these findings suggest that GNPs can enhance performance in sportswear, which not only provides university physical education instructors with high-quality and durable athletic gear but also offers novel insights into the sports equipment industry.

Eggshell membrane powder reinforces adhesive polysaccharide hydrogels for wound repair

Multifunctional polysaccharide hydrogels with strong tissue adhesion, and antimicrobial and hemostatic properties are attractive wound healing materials. In this study, a chitosan-based hydrogel (HCS) was designed, and its properties were enhanced by incorporating oxidized eggshell membrane (OEM). Hydrogel characterization and testing results showed that the hydrogel had excellent antimicrobial properties, cytocompatibility, satisfactory adhesion properties on common substrates, and wet-state adhesion capacity. A rat liver injury model confirmed the significant hemostatic effect of the hydrogel. Finally, the ability of the hydrogel to promote wound healing was verified using rat skin wound repair experiments. Our findings indicate that HCS/OEM hydrogels with added eggshell membrane fibers have better self-healing properties, mechanical strength, adhesion, hemostatic properties, and biocompatibility than HCS hydrogels, in addition to having superior repair performance in wound repair experiments. Overall, the multifunctional polysaccharide hydrogels fabricated in this study are ideal for wound repair.

Sensitive determination of ciprofloxacin with a light-driven photoelectrochemical sensor based on Cu2O/g-C3N4 heterojunctions

Ciprofloxacin (CFX) has excellent bactericidal and antimicrobial properties and is widely used in dairy cattle husbandry. Due to metabolic effects, there is often a certain residue in milk, even a trace amount will pose a threat to humans. Therefore, its facile and sensitive detection is of significant importance. Herein, Cu2O/g-C3N4 heterojunction has been synthesized and its photoelectrochemical (PEC) properties and electron transfer mechanism have been studied. The use of visible light can significantly improve the efficiency of electron migration and the separation of photogenerated electron hole pairs, thus showing higher photoelectric performance for the detection of CFX. In the range of 5.0 ∼1000.0 ng·L−1, the current of Cu2O/g-C3N4 is linearly related to the concentration of CFX and the detection limit is 1.5 ng·L−1. PEC sensor has good long-term stability and selectivity. The practical application of this method is verified by testing commercial samples. Thus, this research provides a feasible PEC sensing platform for routine analysis of other antibiotics in practice.

Fabrication of polyvinyl alcohol/vanillin/Ti3C2Tx/ZnONPs composite film with excellent antimicrobial properties for pepper preservation

Novel food packaging materials with antimicrobial properties must be developed to ensure that fresh agricultural products are free from microbial contamination during the process from “farm” to “table”. Herein, we synthesized an antimicrobial composite packaging film by employing a green in situ synthesis method. The method involves the in situ reduction of zinc oxide nanoparticles (ZnONPs) on the substrate Ti3C2Tx by Lactobacillus plantarum fermentation broth, which was then blended with polyvinyl alcohol and vanillin to obtain the polyvinyl alcohol/vanillin/Ti3C2Tx/ZnONPs (PVA/VAN/T-Z) composite film. The incorporation of crosslinker VAN and antimicrobial material Ti3C2Tx/ZnONPs did not affect the transparency and color of the film, but improved its mechanical strength, hydrophobicity, and antimicrobial ability of the film. Antimicrobial experiments demonstrated that the PVA/VAN/T-Z composite film exhibited significant antimicrobial activity against bacteria (Gram-negative E. coli and Gram-positive S. aureus) and fungi isolated from peppers. Furthermore, pepper preservation experiments demonstrated that the PVA/VAN/T-Z composite film exhibited commendable antimicrobial and preservation performance compared to commercially available film. As a novel antimicrobial packaging material, the multifunctional PVA/VAN/T-Z composite film has a broad application prospect in food preservation.

A Novel Approach for Synthesizing Ultra–Small Silver Nanoparticles Using Covalent Organic Frameworks as Template, Stabilizer and Reductant at Room Temperature

AbstractThe preparation of ultra–small silver nanoparticles (average diameter ≤10 nm) is a technical problem because of their aggregation tendency. Therefore, the preparation conditions are usually harsh and complex. It is widely recognized that covalent organic frameworks (COFs) represent a novel class of porous crystalline compounds with broad applications in various fields. In this work, an environmentally and economically friendly new method has been developed for synthesizing ultra–small silver nanoparticles by reducing silver ions in ethanol solution with a covalent organic framework (TPB–DMTP–COF) as a template and reductant at room temperature. Interestingly, the TPB–DMTP–COF not only serves as a template and reductant but also functions as a stabilizer. Moreover, the TPB–DMTP–COF can be utilized repeatedly as a reductant. The morphology and structure of the silver nanoparticles were examined using transmission electron microscopy and showed that they were spherical with an average particle size of approximately 7.5 nm. Compared with the previously reported silver nanoparticles, the silver nanoparticles synthesized by this new method are not coated with Surfactant, such as Polyvinylpyrrolidone (PVP). As a result, they possess a larger exposed surface area, exhibit increased activity, and demonstrate excellent antimicrobial properties against both Gram–negative Escherichia coli and Gram–positive bacteria Staphylococcus aureus.

Green synthesis, characterization and applications of Phyllanthus emblica fruit extract mediated chromium oxide nanoparticles

The green synthesis of metallic nanoparticles is attributable towards diverse applications in various fields, recently. In this research, we report simple and eco-friendly synthesis of chromium oxide (Cr2O3) nanoparticles using the fruit extract of Phyllanthus emblica as a reducing and capping agent. The absorbance peaks at 350 nm and 450 nm validated the nanoparticle formation in UV–visible spectrum. FTIR spectrum revealed the nature of functional groups. The crystalline properties of nanoparticles were ascertained by XRD analysis. EDX spectrum corroborated the elemental composition of nanoparticles in which chromium and oxygen constituted 68% of total weight. SEM images demonstrated agglomeration of nanoparticles resulting in the formation of large irregularly shaped flakes. Cr2O3 nanoparticles demonstrated excellent antimicrobial properties against 11 bacterial isolates and 1 fungal isolate. The largest inhibition zone (53 mm) was measured against A. baumannii while the smallest inhibition zone (26 mm) was recorded against S. aureus. Minimum inhibitory concentration (MIC) values were < 1 µg/ml for all microbes. However, the synthesized nanoparticles did not reveal synergism with any of the selected antibiotics (FICI values > 1). Nanoparticles possessed potent anti-biofilm powers with maximum (77%) inhibition of E. coli biofilms and minimum (45%) inhibition of S. enterica biofilms. Photocatalytic activity of Cr2O3 nanoparticles was evaluated to determine their efficacy in environmental bioremediation. Outcomes demonstrated degradation of methyl red (84%) but not of methylene blue dye. Furthermore, the Cr2O3 nanoparticles displayed considerable antioxidant (43%) as well as anti-inflammatory (44%) potentials. Hence, the present study accounts for the versatile applications of P. emblica-mediated Cr2O3 nanoparticles which could be pursued for future biomedical and environmental applications.Graphical

Recoverable and degradable carboxymethyl chitosan polyelectrolyte hydrogel film for ultra stable encapsulation of curcumin

Hydrogels have shown great potential for application in food science due to their diverse functionalities. However, most hydrogels inevitably contain toxic chemical cross-linking agent residues, posing serious food safety concerns. In this paper, a curcumin/sodium alginate/carboxymethyl chitosan hydrogels (CSCH) were prepared by self-assembly of two oppositely charged polysaccharides, carboxymethyl chitosan and sodium alginate, to form a three-dimensional network encapsulating curcumin for extending food shelf life. The network structure of the CSCH film confirmed by FTIR, XRD, and XPS was mainly formed by electrostatic interactions. The chemical stability of CSCH network encapsulated curcumin was 4.2 times greater than that of free curcumin, with excellent gas barrier, antimicrobial, antioxidant, and biosafety properties. It was found that CSCH films reduced dehydration, prevented nutrient loss, inhibited microbial growth, and lowered the respiration rate, which effectively maintained the quality of mango and prolonged its shelf-life up to 11 days. Notably, CSCH films possessed the properties of rapid recycling (10 mins) and biodegradability (53 days). This polysaccharide-based hydrogel film provides a viable strategy for the development of green and sustainable food packaging.