A mechanistic study of the antibacterial effect of silver ions on Escherichia coli and Staphylococcus aureus

Improving the particulate matter filtration, antibacterial, and degradation properties of electrospinning poly(lactic acid) membranes with ZIF-8@chitosan

In order to improve the filtration efficiency of electrospinning poly(lactic acid) (PLA) membrane on particulate matter (PM), endow the membrane with good antibacterial properties, and accelerate the degradation effect of PLA materials in natural water and soil environments, ZIF-8@chitosan (ZIF-8@CS) was prepared by in situ growth method and was combined with PLA to manufacture the PLA/ZIF-8@CS electrospinning membranes. The PLA/ZIF-8@CS (3 wt%) membrane exhibited filtration efficiencies of 96.79 % for PM2.5 and 91.21 % for PM10, which were significantly higher than that of PP melt-blown cloth. Due to the inherently positive charge and the synergistic interaction between CS and ZIF-8, the antibacterial rates of PLA/ZIF-8@CS membranes were up to 100 % for E. coli and S. aureus after contact for 8 h. The addition of ZIF-8@CS in the membranes also influenced the degradation behavior of PLA/ZIF-8@CS membranes evidently.

Synthesis and analysis of multifunctional graphene oxide/Ag2O-PVA/chitosan hybrid polymeric composite for wound healing applications

The requirement for accurate treatments for skin diseases and wounds, generated a rising interest towards multifunctional polymer composites, that are capable of mimicking the natural compositions in human body. Also, electroactive composite films disseminate endogenous electrical stimulations that encourage cell migration and its proliferation at wound site, proposing greater opportunities in upgrading the conventional wound patches. In this work, the composite film made of graphene oxide, Ag2O, PVA and chitosan were developed for wound healing applications, by the solution casting method. The even dispersibility of nanofiller in polymeric matrix was validated from the physicochemical analyses. The increment in roughness of the composite film surface was noted from AFM images. The thermal stability and porous nature of the polymer composite were also verified. A conductivity value of 0.16 × 10-4 Scm-1 was obtained for the film. From MTT assay, it was noted that the films were non-cytotoxic and supported cell adhesion along with cell proliferation of macrophage (RAW 264.7) cells. Moreover, the composite film also demonstrated non-hemolytic activity of <2 %, as well as excellent antibacterial activity towards E. coli and S. aureus. Thus, the obtained results validated that the prepared composite film could be chosen as an innovative candidate for developing state-of-the-art wound dressings.

Designing antibacterial materials through simulation and theory

Antibacterial materials have a wide range of potential applications in bio-antimicrobial, environmental antimicrobial, and food antimicrobial fields due to their intrinsic antimicrobial properties, which can circumvent the development of drug resistance in bacteria. Understanding the intricate mechanisms and intrinsic nature of diverse antibacterial materials is significant for the formulation of guidelines for the design of materials with rapid and efficacious antimicrobial action and a high degree of biomedical material safety. Herein, this review highlights the recent advances in investigating antimicrobial mechanisms of different antibacterial materials with a particular focus on tailored computer simulations and theoretical analysis. From the view of structure and function, we summarize the characteristics and mechanisms of different antibacterial materials, introduce the latest advances of new antibacterial materials, and discuss the design concept and development direction of new materials. In addition, we underscore the significance of employing simulation and theoretical methodologies to elucidate the intrinsic antimicrobial mechanisms, which is crucial for a comprehensive comprehension of the control strategies, safer biomedical applications, and the management of health and environmental concerns associated with antibacterial materials. This review could potentially stimulate further endeavors in fundamental research and facilitate the extensive utilization of computational and theoretical approaches in the design of novel functional nanomaterials.

Low Silver/Copper Exchange in a Copper-Phosphate Enzyme Nanoflower Hybrid Extremely Enhanced Antimicrobial Efficacy against Multidrug Resistant Bacteria

Infections caused by bacteria that are resistant to many drugs are a major threat to public health in many countries around the world. Here we demonstrate the creation of heterogeneous catalytic nanomaterials with outstanding antimicrobial properties against several superbugs. We have shown that replacing a small amount of copper in a generated copper-phosphate-enzyme nanoflower hybrid with silver drastically increases the antimicrobial capacity of the nanomaterial. In this sense, it has been confirmed that the exchange generated silver phosphate nanoparticles on the Cu nanoflowers, with control of the nanoparticle diameter size. The Fenton catalytic activity of the Ag-containing nanobiohybrids was affected, showing better performance with lower amounts of silver in the final hybrid. This effect was confirmed by their antimicrobial efficacy against Escherichia coli, where the Ag4Cu32@CALB hybrid displayed a log reduction of 3.9, an efficiency more than 5000 times higher than that obtained with copper nanoflowers (Cu36@CALB). The hybrid also showed excellent efficacy against other bacteria such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Mycobacterium smegmatis with log reductions of 7.6, 4.3, and 1.8, respectively.

Bio-Based Thermosetting Resins: From Molecular Engineering to Intrinsically Multifunctional Customization

Recent years have witnessed a growing interest in bio-based thermosetting resins in terms of environmental concerns and the desire for sustainable industrial practices. Beyond sustainability, utilizing the structural diversity of renewable feedstock to craft bio-based thermosets with customized functionalities is very worthy of expectation. There exist many bio-based compounds with inherently unique chemical structures and functions, some of which are even difficult to synthesize artificially. Over the past decade, great efforts are devoted to discovering/designing functional properties of bio-based thermosets, and notable progress have been made in antibacterial, antifouling, flame retardancy, serving as carbon precursors, and stimuli responsiveness, among others, largely expanding their application potential and future prospects. In this review, recent advances in the field of functional bio-based thermosets are presented, with a particular focus on molecular structures and design strategies for discovering functional properties. Examples are highlighted wherein functionalities are facilitated by the inherent structures of bio-based feedstock. Perspectives on issues regarding further advances in this field are proposed at the end.

Synthesis, characterization and evaluation of in vitro potential antimicrobial efficiency of new chitosan hydrogels and their CuO nanocomposites

The phenomenon of microbial resistance and its resulting biofilms to traditional antibiotics is worsening over time. Therefore, the discovery of alternative substances that inhibit microbial activities through mechanisms different from those of known antibiotics requires attention. So, chitosan was crosslinked using different amounts of oxalyl dihydrazide yielding four novel hydrogels; ODHCs-I, ODHCs-II, ODHCs-III, and ODHCs-IV of crosslinking degree 12.17, 20.67, 31.67, and 43.17, respectively. Different amounts of CuO nanoparticles were impregnated into ODHCs-IV, obtaining ODHCs-IV/CuONPs-1 %, ODHCs-IV/CuONPs-3 % and ODHCs-IV/CuONPs-5 % composites. Their structure was emphasized using FTIR, SEM, XRD, TEM, EDX and elemental analysis. Their in vitro antimicrobial and anti-biofilm activities improved with increasing ODH and CuONPs content. ODHCs-IV exhibited minimal inhibition concentration (2 μg/mL) against S. pyogenes that was much lower than Vancomycin (3.9 μg/mL). ODHCs-IV/CuONPs-5 % displayed better inhibition performance than Vancomycin and Amphotericin B against Gram-positive-bacteria and fungi, respectively, and comparable one to that of Vancomycin against Gram-negative-bacteria. ODHCs-IV/CuONPs-5 % displayed much lower minimal biofilm inhibition concentrations (1.95 to 3.9 μg/mL) as compared with those of ODHCs-IV (7.81 and 15.63 μg/mL), against C. albicans, S. pyogenes, and K. pneumonia. ODHCs-IV/CuONPs-5 % composite is safe on normal human cells. Oxalyl dihydrazide and CuONPs amalgamated into chitosan in one formulation promoted its antimicrobial efficiency.

Biosynthesis of Polyhydroalkanoates Doped with Silver Nanoparticles Using Pseudomonas putida and Pseudomonas aeruginosa for Antibacterial Polymer Applications

In this study, the biosynthesis of polyhydroxyalkanoates (PHAs) was carried out using Pseudomonas putida and Pseudomonas aeruginosa. These PHAs were produced using reagent-grade glycerol and crude glycerol as the carbon sources. The objective was to compare the production of PHAs and to functionalize these polymers with silver nanoparticles to provide antibacterial properties for potential biomedical applications. The findings from the physical and chemical analyses confirmed the successful synthesis and extraction of PHAs, achieving comparable yields using both crude glycerol and reagent-grade glycerol as carbon sources across both strains. Approximately 16% higher PHAs production was obtained using Pseudomonas putida compared to Pseudomonas aeruginosa, and no significant difference was observed in the production rate of PHAs between the two carbon sources used, which means that crude glycerol could be utilized even though it has more impurities. Notably, PHAs functionalized with silver nanoparticles showed improved antibacterial effectiveness, especially those derived from reagent-grade glycerol and the Pseudomonas aeruginosa strain.

Biocompatible Co-organic Composite Thin Film Deposited by VHF Plasma-Enhanced Atomic Layer Deposition at a Low Temperature

Although metal-organic thin films are required for many biorelated applications, traditional deposition methods have proven challenging in preparing these composite materials. Here, a Co-organic composite thin film was prepared by plasma-enhanced atomic layer deposition (PEALD) with cobaltocene (Co(Cp)2) on polydimethylsiloxane (PDMS), using two very high frequency (VHF) NH3 plasmas (60 and 100 MHz), for use as a tissue culture scaffold. VHF PEALD was employed to reduce the temperature and control the thickness and composition. In the result of the VHF PEALD process, the Young's modulus of the Co-organic composite thin film ranged from 82.0 ± 28.6 to 166.0 ± 15.2 MPa, which is similar to the Young's modulus of soft tissues. In addition, the deposited Co ion on the Co-organic composite thin film was released into the cell culture media under a nontoxic level for the biological environment. The proliferation of both L929, the mouse fibroblast cell line, and C2C12, the mouse myoblast cell line, increased to 164.9 ± 23.4% during 7 days of incubation. Here, this novel bioactive Co-organic composite thin film on an elastic PDMS substrate enhanced the proliferation of L929 and C2C12 cell lines, thereby expanding the application range of VHF PEALD in biological fields.

Biogenic silver nanoparticle synthesis using orange peel extract and its multifaceted biomedical application

The aim of this study was to employ an agro-industrial byproduct, specifically Citrus sinensis peels, as a reservoir of polyphenols. The natural chemicals present in C. sinensis peels serve as reducing agents in an environmentally benign method for synthesizing silver nanoparticles (AgNPs). This methodology not only provides a more environmentally friendly method for synthesizing nanoparticles but also enhances the value of agricultural waste, emphasizing the sustainable utilization of resources. In our study, AgNPs were successfully synthesized using peel aqueous exact of C. sinensis and then their various biological activity has been investigated. The synthesized AgNPs were characterized by UV-vis spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscopy (TEM) analysis. Furthermore, their effectiveness in inhibiting growth and biofilm formation of Escherichia coli, Staphylococcus aureus, and Candida albicans has been investigated. The minimum inhibitory concentrations (MIC) for E. coli and S. aureus were both 32 μg/mL, and for C. albicans, it was 128 µg/mL. At 250 µg/mL of AgNPs, 94% and 92% biofilm inhibition were observed against E. coli and S. aureus, respectively. Furthermore, AgNPs demonstrated significant toxic effects against human prostate cancer cell line DU145 as investigated by anti-apoptotic, 4',6-diamidino-2-phenylindole (DAPI), reactive oxygen species (ROS), and acridine orange/ethidium bromide (AO/EtBr) assays. We also conducted uptake analysis on these pathogens and cancer cell lines to preliminarily investigate the mechanisms underlying their toxic effects. These findings confirm that AgNPs can serve as a cost-effective, non-toxic, and environmentally friendly resource for green synthesis of medicinal AgNPs. Moreover, this approach offers an alternative recycling strategy that contributes to the sustainable use of biological by-products.

Temporal and dosage impact of magnesium oxide nanoparticles on grass carp: unveiling oxidative stress, DNA damage, and antioxidant suppression

Magnesium oxide nanoparticles (MgO NPs) have gained significant importance in biomedicine and variety of nanotechnology-based materials used in the agriculture and biomedical industries. However, the release of different nanowastes in the water ecosystem becomes a serious concern. Therefore, this study was executed to evaluate the toxic impacts of MgO NPs on grass carp. A total of 60 grass carp were randomly divided in three groups (G0, G1, and G2). Fish reared in group G0 were kept as control while fish of groups G1 and G2 were exposed to 0.5 mg/L and 0.7 mg/L MgO NPs, respectively, mixed in water for 21 days. The 96h median lethal concentration (LC50) of MgO NPs was found to be 4.5 mg/L. Evaluation of oxidative stress biomarkers, antioxidant enzymes, DNA damage in different visceral organs and the presence of micronuclei in erythrocytes were determined on days 7, 14, and 21 of the trial. Results revealed dose- and time-dependent significantly increased values of reactive oxygen species, lipid peroxidation product, DNA damage in multiple visceral organs and formation of micronuclei in the erythrocytes of treated fish (0.7 mg/L). The results on antioxidant profile exhibited significantly lower amounts of total proteins, catalase, superoxide dismutase, and peroxidase in visceral organs of the fish exposed to MgO NPs (0.5 and 0.7 mg/L) at day 21 of trial compared to control group. In conclusion, it has been recorded that MgO NPs severely influence the normal physiological functions of the grass carp even at low doses.

Advancements in Nanoparticle-Based Strategies for Enhanced Antibacterial Interventions

The escalating global threat of antibiotic resistance underscores the urgent need for innovative antimicrobial strategies. This review explores the cutting-edge applications of nanotechnology in combating bacterial infections, addressing a critical healthcare challenge. We critically assess the antimicrobial properties and mechanisms of diverse nanoparticle systems, including liposomes, polymeric micelles, solid lipid nanoparticles, dendrimers, zinc oxide, silver, and gold nanoparticles, as well as nanoencapsulated essential oils. These nanomaterials offer distinct advantages, such as enhanced drug delivery, improved bioavailability, and efficacy against antibiotic-resistant strains. Recent advancements in nanoparticle synthesis, functionalization, and their synergistic interactions with conventional antibiotics are highlighted. The review emphasizes biocompatibility considerations, stressing the need for rigorous safety assessments in nanomaterial applications. By synthesizing current knowledge and identifying emerging trends, this review provides crucial insights for researchers and clinicians aiming to leverage nanotechnology for next-generation antimicrobial therapies. The integration of nanotechnology represents a promising frontier in combating infectious diseases, underscoring the timeliness and imperative of this comprehensive analysis.

Synergistic Coassembly of Folic Acid-Based Supramolecular Polymer with a Covalent Polymer Toward Fabricating Functional Antibacterial Biomaterials

Supramolecular biomaterials can recapitulate the structural and functional facets of the native extracellular matrix and react to biochemical cues, leveraging the unique attributes of noncovalent interactions, including reversibility and tunability. However, the low mechanical properties of supramolecular biomaterials can restrict their utilization in specific applications. Combining the advantages of supramolecular polymers with covalent polymers can lead to the fabrication of tailor-made biomaterials with enhanced mechanical properties/degradability. Herein, we demonstrate a synergistic coassembled self-healing gel as a multifunctional supramolecular material. As the supramolecular polymer component, we chose folic acid (vitamin B9), an important biomolecule that forms a gel comprising one-dimensional (1D) supramolecular polymers. Integrating polyvinyl alcohol (PVA) into this supramolecular gel alters its ultrastructure and augments its mechanical properties. A drastic improvement of complex modulus (G*) (∼3674 times) was observed in the folic acid-PVA gel with 15% w/v PVA (33215 Pa) compared with the folic acid gel (9.04 Pa). The coassembled hydrogels possessed self-healing and injectable/thixotropic attributes and could be printed into specific three-dimensional (3D) shapes. Synergistically, the supramolecular polymers of folic acid also improve the toughness, durability, and ductility of the PVA films. A nanocomposite of the gels with silver nanoparticles exhibited excellent catalytic efficiency and antibacterial activity. The folic acid-PVA coassembled gels and films also possessed high cytocompatibility, substantiated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and live-dead assays. Taken together, the antibacterial and cell-adhesive attributes suggest potential applications of these coassembled biomaterials for tissue engineering and wound healing.

Banana peel extract for CeO2 nanoflower synthesis: Enhancing photocatalytic activity for methyl orange dye removal and bactericidal effects

The cube architecture associated with the CeO2 nanoflowers (NFs) that generated, which had an average crystallization width of 7 nm, has been confirmed by X-ray crystallographic investigations. The method used is environmentally acceptable since it converts wasted banana peel extracts into CeO2 nanoflower. On the basis of artwork obtained from a High-Resolution Transmission Electron Microscope (HR-TEM), CeO2 nanoparticles have been observed to possess a spherical shape and an average particle diameter of 21 nm. To take the purpose of this study, green-fabricated CeO2-NFs were used to investigate the photocatalytic oxidation of methyl orange (MO) dye when exposed to sunshine. CeO2 nanofibers showed a degradation performance of 98% when compared to methyl orange dye. Evidently is a possibility that this may be caused by the presence of CeO2 nanoflowers, whereby enhance the interaction of electrons, which are holes dissolution, and adherence. Upon a single day of being exposed, the biocidal potential was tested against both gram-positive and gram-negative bacteria, including E. coli, B. cereus, and S. aureus, among others. Due to the fact that its 32 mm minimum inhibitory concentration (MIC) for B. cereus was the highest among conventional medicines. As shown by the extraordinary capabilities of WBP@CeO2 tiny particles, manipulating of flexible tiny particles to feed the purpose of achieving effective and customizable infections and dermatologist advancements is really stunning.

Silver-Doped Titanium Oxide Layers for Improved Photocatalytic Activity and Antibacterial Properties of Titanium Implants

Titanium has a long history of clinical use, but the naturally forming oxide is not ideal for bacterial resistance. Anodization processes can modify the crystallinity, surface topography, and surface chemistry of titanium oxides. Anatase, rutile, and mixed phase oxides are known to exhibit photocatalytic activity (PCA)-driven bacterial resistance under UVA irradiation. Silver additions are reported to enhance PCA and reduce bacterial attachment. This study investigated the effects of silver-doping additions to three established anodization processes. Silver doping showed no significant influence on oxide crystallinity, surface topography, or surface wettability. Oxides from a sulfuric acid anodization process exhibited significantly enhanced PCA after silver doping, but silver-doped oxides produced from phosphoric-acid-containing electrolytes did not. Staphylococcus aureus attachment was also assessed under dark and UVA-irradiated conditions on each oxide. Each oxide exhibited a photocatalytic antimicrobial effect as indicated by significantly decreased bacterial attachment under UVA irradiation compared to dark conditions. However, only the phosphorus-doped mixed anatase and rutile phase oxide exhibited an additional significant reduction in bacteria attachment under UVA irradiation as a result of silver doping. The antimicrobial success of this oxide was attributed to the combination of the mixed phase oxide and higher silver-doping uptake levels.

The Highly Durable Antibacterial Gel-like Coatings for Textiles

Hospital-acquired infections are considered a priority for public health systems since they pose a significant burden for society. High-touch surfaces of healthcare centers, including textiles, provide a suitable environment for pathogenic bacteria to grow, necessitating incorporating effective antibacterial agents into textiles. This paper introduces a highly durable antibacterial gel-like solution, Silver Shell™ finish, which contains chitosan-bound silver chloride microparticles. The study investigates the coating's environmental impact, health risks, and durability during repeated washing. The structure of the Silver Shell™ finish was studied using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The TEM images showed a core-shell structure, with chitosan forming a protective shell around groupings of silver microparticles. The field-emission scanning electron microscopy (FESEM) demonstrated the uniform deposition of Silver Shell™ on the surfaces of the fabrics. AATCC Test Method 100 was employed to quantitatively analyze the antibacterial properties of the fabrics coated with silver microparticles. Two types of bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), were used in this study. The antibacterial results showed that after 75 wash cycles, a 100% reduction for both S. aureus and E. coli in the coated samples using crosslinking agents was observed. The coated samples without a crosslinking agent exhibited 99.88% and 99.81% reductions for S. aureus and E. coli after 50 washing cycles. To compare the antibacterial properties toward non-pathogenic and pathogenic strains of the same species, MG1655 model E. coli strain (ATCC 29213) and a multidrug-resistant clinical isolate were used. The results showed the antibacterial efficiency of the Silver ShellTM solution (up to 99.99% reduction) coated on cotton fabric. AATCC-147 was performed to investigate the coated samples' leaching properties and the crosslinking agent's effects against S. aureus and E. coli. All coated samples demonstrated remarkable antibacterial efficacy, even after 75 wash cycles. The crosslinking agent facilitated durable attachment between the silver microparticles and cotton substrate, minimizing the release of particles from the fabrics. Color measurements were conducted to assess the color differences resulting from the coating process. The results indicated fixation values of 44%, 32%, and 28% following 25, 50, and 75 washing cycles, respectively.

Synthesis of Silver Nanoparticles from Aeromonas caviae for Antibacterial Activity and In Vivo Effects in Rats

Silver nanoparticles (AgNPs) have excellent antimicrobial properties, as they can inhibit multidrug-resistant (MDR) pathogens. Furthermore, bio-AgNPs have potential applications in medicine due to their low toxicity and high stability. Here, AgNPs were synthesized from the biomass of Aeromonas caviae isolated from a sediment sample and subsequently characterized. The UV-Vis spectra of AgNPs in aqueous medium peaked at 417 nm, matching their plasmon absorption. The X-ray diffraction analysis (XRD) pattern of AgNPs showed four peaks at 2θ values, corresponding to Ag diffraction faces. Absorption band peaks at 3420.16, 1635.54, and 1399.43 cm-1 were identified by Fourier-transform infrared spectroscopy (FTIR) analysis as belonging to functional groups of AgNP-associated biomolecules. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the nanoparticles are spherical and pseudospherical, with sizes of 15-25 nm. Agar well diffusion minimal inhibitory concentration (MIC) assays were used to assess the antibacterial activity of the nanoparticles against MDR pathogens. AgNPs exhibited antibacterial activity against MDR bacteria. Two groups of albino rats received intraperitoneal injections of AgNPs at 15 mg/kg or 30 mg/kg for 7 days. Blood, kidney, and liver samples were collected to investigate hematological, biochemical, and histopathological alterations. Administered AgNPs in rats fluctuated in liver and kidney function parameters. The ultrastructural impacts of AgNPs were more prominent at higher doses. The results proved the easy, fast, and efficient synthesis of AgNPs using A. caviae isolates and demonstrated the remarkable potential of these AgNPs as antibacterial agents. Nanotoxicological studies are required to identify the specific dose that balances optimal antibacterial activity with minimal toxicity to human health.

Polyalthia longifolia-mediated green synthesis of zinc oxide nanoparticles: characterization, photocatalytic and antifungal activities

The biological synthesis of zinc oxide nanoparticles (ZnO NPs) from plant extracts has emerged as a novel method for producing NPs with great scalability and biocompatibility. The present study is focused on bio-fabricated zinc oxide nanomaterial characterization and investigation of its photocatalytic and antifungal activities. ZnO NPs were biosynthesized using the leaf extract of Polyalthia longifolia without using harmful reducing or capping chemicals, which demonstrated fungicidal activity against Fusarium oxysporum f. sp. ciceris. The results showed that the inhibition of the radial growth of F. oxysporum f. sp. ciceris was enhanced as the concentration increased from 100 ppm to 300 ppm. The effectiveness of the photocatalytic activity of biosynthesized ZnO NPs was analyzed using MB dye degradation in aqueous medium under ultraviolet (UV) radiation and natural sunlight. After four consecutive cycles, the photocatalytic degradation of MB was stable and was 84%, 83%, 83%, and 83%, respectively, during natural sunlight exposure. Under the UV sources, degradation reached 92%, 89%, 88%, and 87%, respectively, in 90 minutes. This study suggests that the ZnO NPs obtained from plant extract have outstanding photocatalytic and antifungal activities against F. oxysporum f. sp. ciceris and have the potential for application as a natural pest control agent to reduce pathogenesis.

Unraveling the mysteries of silver nanoparticles: synthesis, characterization, antimicrobial effects and uptake translocation in plant-a review

MAIN CONCLUSION

The study thoroughly investigates nanosilver production, properties, and interactions, shedding light on its multifaceted applications. It underscores the importance of characterizing nanosilver for predicting its behavior in complex environments. Particularly, it highlights the agricultural and environmental ramifications of nanosilver uptake by plants. Nowadays, silver nanoparticles (AgNPs) are a very adaptable nanomaterial with many uses, particularly in antibacterial treatments and agricultural operations. Clarification of key elements of nanosilver, such as its synthesis and characterization procedures, antibacterial activity, and intricate interactions with plants, particularly those pertaining to uptake and translocation mechanisms, is the aim of this in-depth investigation. Nanosilver synthesis is a multifaceted process that includes a range of methodologies, including chemical, biological, and sustainable approaches that are also environmentally benign. This section provides a critical evaluation of these methods, considering their impacts on repeatability, scalability, and environmental impact. The physicochemical properties of nanosilver were determined by means of characterization procedures. This review highlights the significance of analytical approaches such as spectroscopy, microscopy, and other state-of the-art methods for fully characterizing nanosilver particles. Although grasp of these properties is necessary in order to predict the behavior and potential impacts of nanosilver in complex biological and environmental systems. The second half of this article delves into the intricate interactions that plants have with nanosilver, emphasizing the mechanisms of absorption and translocation. There are significant ramifications for agricultural and environmental problems from the uptake of nanosilver by plants and its subsequent passage through their tissues. In summary, by summarizing the state-of-the-art information in this field, this study offers a comprehensive overview of the production, characterization, antibacterial capabilities, and interactions of nanosilver with plants. This paper contributes to the ongoing conversation in nanotechnology.

Green synthesis of silver nanoparticle prepared with Ocimum species and assessment of anticancer potential

Silver nanoparticles (AgNPs) have gained much attention due to their unique physical, and chemical properties. Integration of phytochemicals in nanoformulation might have higher applicability in healthcare. Current work demonstrates the synthesis of green AgNPs with O. gratissimum (gr-AgNPs) O. tenuiflorum (te-AgNPs) and O. americanum (am-AgNPs) followed by an evaluation of their antimicrobial and anticancer properties. SEM analysis revealed spherical-shaped particles with average particle sizes of 69.0 ± 5 nm for te-AgNPs, 46.9 ± 9 nm for gr-AgNPs, and 58.5 ± 18.7 nm for am-AgNPs with a polydispersity index below 0.4. The synthesized am-AgNPs effectively inhibited Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, Aspergillus niger, and Candida albicans with 23 ± 1.58 mm, 20 ± 1.68 mm, 22 ± 1.80 mm, 26 ± 1.85 mm, and 22 ± 1.40 nm of zone of inhibition respectively. Synthesized AgNPs also induced apoptotic cell death in MCF-7 in concentration-dependent manner. IC50 values for am-AgNPs, te-AgNPs, and gr-AgNPs were 14.78 ± 0.89 µg, 18.04 ± 0.63 and 15.41 ± 0.37 µg respectively which suggested that am-AgNPs were the most effective against cancer. At higher dose size (20 µg) AgNPs were equally effective to commercial standard Doxorubicin (DOX). In comparison to te-AgNPs and gr-AgNPs, am-AgNPs have higher in vitro anticancer and antimicrobial effects. The work reported Ocimum americanum for its anticancer properties with chemical profile (GCMS) and compared it with earlier reported species. The activity against microbial pathogens and selected cancer cells clearly depicted that these species have distinct variations in activity. The results have also emphasized on higher potential of biogenic silver nanoparticles in healthcare but before formulation of commercial products, detailed analysis is required with human and animal models.

Green Synthesis and Characterization of Biologically Synthesized and Antibiotic-Conjugated Silver Nanoparticles followed by Post-Synthesis Assessment for Antibacterial and Antioxidant Applications

The paper presents the antibacterial and antioxidant activities of silver nanoparticles (AgNPs) when conjugated with two antibiotics levofloxacin and ciprofloxacin as well as biologically synthesized nanoparticles from Moringa oleifera and Curcuma longa. Leaves of Moringa and powder of Curcuma were used in the green synthesis of silver nanoparticles. Ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used for the characterization of the synthesized silver nanoparticles. Comparison of levofloxacin and ciprofloxacin and their conjugated AgNPs was also studied for antibacterial and antioxidant activity. The synthesis of Moringa-AgNPs, turmeric-AgNPs, levofloxacin-AgNPs, and ciprofloxacin-AgNPs was confirmed by UV spectroscopy. An absorption peak value of 400-450 nm was observed, and light to dark brown color indicated the synthesis of AgNPs. Moringa-AgNPs revealed high antioxidant activity (80.3 ± 3.14) among all of the synthesized AgNPs. Lev-AgNPs displayed the highest zone of inhibition for Staphylococcus aureus, while in Escherichia coli, Cip-AgNPs showed high antibacterial activity. Furthermore, AgNPs synthesized using green methods exhibit high and efficient antimicrobial activities against two food-borne pathogens. Biologically synthesized nanoparticles exhibited antibacterial activity against E. coli (13.73 ± 0.46 with Tur-AgNPs and 13.53 ± 0.32 with Mor-AgNPs) and S. aureus (14.16 ± 0.24 with Tur-AgNPs and 13.36 ± 0.77 with Mor-AgNPs) by using a well diffusion method with significant shrinkage and damage of the bacterial cell wall, whereas antibiotic-conjugated nanoparticles showed high antibacterial activity compared to biologically synthesized nanoparticles with 14.4 ± 0.37 for Cip-AgNPs and 13.93 ± 0.2 for Lev-AgNPs for E. coli and 13.3 ± 0.43 for Cip-AgNPs and 14.33 ± 0.12 for Lev-AgNPs for S. aureus. The enhanced efficiency of conjugated silver nanoparticles is attributed to their increased surface area compared to larger particles. Conjugation of different functional groups contributes to improved reactivity, creating active sites for catalytic reactions. Additionally, the precise control over the size and shape of green-synthesized nanoparticles further augments their catalytic and antibiotic activities.

Multidrug-Resistant Escherichia coli Remains Susceptible to Metal Ions and Graphene-Based Compounds

Escherichia coli is listed as a priority 1 pathogen on the World Health Organization (WHO) priority pathogen list. For this list of pathogens, new antibiotics are urgently needed to control the emergence and spread of multidrug-resistant strains. This study assessed eighteen metal ions, graphene, and graphene oxide for their antimicrobial efficacy against E. coli in both planktonic and biofilm growth states and the potential synergy between metal ions and graphene-based compounds. Molybdenum and tin ions exhibited the greatest antimicrobial activity against the planktonic states of the isolates with minimal inhibitory concentrations (MIC) ranging between 13 mg/L and 15.6 mg/L. Graphene oxide had no antimicrobial effect against any of the isolates, while graphene showed a moderate effect against E. coli (MIC, 62.5 mg/L). Combinations of metal ions and graphene-based compounds including tin-graphene, tin-graphene oxide, gold-graphene, platinum-graphene, and platinum-graphene oxide exhibited a synergistic antimicrobial effect (FIC ≤ 0.5), inhibiting the planktonic and biofilm formation of the isolates regardless of their antibiotic-resistant profiles. The bactericidal effect of the metal ions and the synergistic effects when combined with graphene/graphene oxide against medically relevant pathogens demonstrated that the antimicrobial efficacy was increased. Hence, such agents may potentially be used in the production of novel antimicrobial/antiseptic agents.

Synthesis, Characterization, and Evaluation of the Antimicrobial Effects and Cytotoxicity of a Novel Nanocomposite Based on Polyamide 6 and Trimetaphosphate Nanoparticles Decorated with Silver Nanoparticles

This study aimed to develop a polymeric matrix of polyamide-6 (P6) impregnated with trimetaphosphate (TMP) nanoparticles and silver nanoparticles (AgNPs), and to evaluate its antimicrobial activity, surface free energy, TMP and Ag+ release, and cytotoxicity for use as a support in dental tissue. The data were subjected to statistical analysis (p < 0.05). P6 can be incorporated into TMP without altering its properties. In the first three hours, Ag+ was released for all groups decorated with AgNPs, and for TMP, the release only occurred for the P6-TMP-5% and P6-TMP-10% groups. In the inhibition zones, the AgNPs showed activity against both microorganisms. The P6-TMP-2.5%-Ag and P6-TMP-5%-Ag groups with AgNPs showed a greater reduction in CFU for S. mutans. For C. albicans, all groups showed a reduction in CFU. The P6-TMP groups showed higher cell viability, regardless of time (p < 0.05). The developed P6 polymeric matrix impregnated with TMP and AgNPs demonstrated promising antimicrobial properties against the tested microorganisms, making it a potential material for applications in scaffolds in dental tissues.

Antibacterial coating of orthodontic elastomeric ligatures with silver and bismuth nanofilms by magnetron sputtering: A feasibility study

OBJECTIVES

Magnetron sputtering was evaluated to equip surfaces of orthodontic elastomeric ligatures with silver and bismuth nanofilms.

MATERIAL AND METHODS

Antibacterial properties were evaluated by the adhesion of Streptococcus mutans. Polyurethane-based elastomeric ligatures were coated with silver and bismuth nanofilms via direct current magnetron sputtering. Surface roughness (Ra ) and surface-free energy (SFE) were assessed. Coated specimens were incubated with S. mutans for 2 h. Adhering bacteria were visualized by Hoechst staining and quantified by an ATP-based luminescence assay. One-way analysis of variance with Tukey post hoc testing and Pearson correlation analysis were performed (p < .05) to relate bacterial adhesion to surface roughness and surface-free energy.

RESULTS

Elastomeric ligatures were successfully coated with silver and bismuth nanofilms. Ra was significantly reduced by silver coating. Silver and bismuth coatings showed significantly higher SFE than controls. Adhesion of S. mutans was significantly decreased by silver coating. No correlation between bacterial adhesion and SFE was found. Correlation between bacterial adhesion and Ra was positive but not statistically significant.

CONCLUSIONS

Magnetron sputtering proved to be a feasible method to equip orthodontic elastomeric ligatures with silver and bismuth nanofilms. Silver coatings of elastomeric ligatures may reduce white spots and carious lesions in orthodontic patients. Future research is required to stabilize coatings.

Comparative Evaluation of Penetration of Various Nano-sized Intra-canal Medicaments: An In Vitro Confocal Laser Scanning Microscopic Study

Background

To assess and contrast the depth of penetration of conventional calcium hydroxide, nanoparticle calcium hydroxide, silver nanoparticles, and combination of nanoparticle calcium hydroxide and silver nanoparticles into dentinal tubules using confocal laser scanning microscope.

Materials and Methods

Eighty human single-rooted teeth were decoronated and instrumented up to Protaper Universal F3. Teeth were separated into four groups at random (n = 20) following chemomechanical preparation. Group 1: Control Conventional Calcium Hydroxide; Group 2: Nanoparticle Calcium Hydroxide; group 3: Silver Nanoparticles; group 4: Combination of Nanoparticle Calcium Hydroxide and Silver Nanoparticles. With the use of lentulo spirals, medications were injected into the canals, stirred up with ultrasound, and then kept at 37°C for 24 hours. A 1 mm thick slice was obtained at 5 mm from the root apex by sectioning the root perpendicular to the long axis of the tooth and then put on a glass slide to measure the depth of penetration using a confocal laser microscope.

Statistical Analysis

To quantify the depth of penetration among the four groups, a one-way ANOVA was used and post hoc-Tukey's test was used to compare between groups.

Results

All of the groups were statistically significant, with group 4 showing the greatest depth of penetration, followed by group 2 and group 3. In contrast, all other groups in the intergroup comparison were statistically significant (P value 0.05) aside from the comparison of group 2 to group 3.

Conclusion

Silver nanoparticles and nanoparticle calcium hydroxide together demonstrated greater penetration than calcium hydroxide, silver nanoparticles, and nanoparticle calcium hydroxide alone.

Visible-Light-Driven Mentha spicata L.-Mediated Ag-Doped Bi2Zr2O7 Nanocomposite for Enhanced Degradation of Organic Pollutants, Electrochemical Sensing, and Antibacterial Applications

Novel visible-light-driven Ag (X)-doped Bi2Zr2O7 (BZO) nanocomposites in pudina (P) extract (Mentha spicata L.), X-1, 3, 5, 7, and 9 mol %, were synthesized by the one-pot greener solution combustion method. The as-synthesized nanocomposite materials were characterized by using various spectral [X-ray diffraction (XRD), Fourier transform infrared, UV-visible, UV- diffuse reflectance spectra, X-ray photoelectron spectroscopy], electrochemical (cyclic voltammetry, electrochemical impedance spectroscopy), and analytical (scanning electron microscopy-energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller) techniques. The average particle size of the nanocomposite material was found to be between 14.8 and 39.2 nm by XRD. The well-characterized Ag-doped BZOP nanocomposite materials exhibited enhanced photocatalytic degradation activity toward hazardous dyes such as methylene blue (MB) and rose bengal (RB) under visible light irradiation ranges between 400 and 800 nm due to their low energy band gap. As a result, 7 mol % of Ag-doped BZOP nanocomposite material exhibited excellent photodegradation activity against MB (D.E. = 98.7%) and RB (D.E. = 99.3%) as compared to other Ag-doped BZOP nanocomposite materials and pure BZOP nanocomposite, respectively, due to enhanced semiconducting and optical behaviors, high binding energy, and mechanical and thermal stabilities. The Ag-doped BZOP nanocomposite material-based electrochemical sensor showed good sensing ability toward the determination of lead nitrate and dextrose with the lowest limit of detection (LOD) of 18 μM and 12 μM, respectively. Furthermore, as a result of the initial antibacterial screening study, the Ag-doped BZOP nanocomposite material was found to be more effective against Gram-negative bacteria (Escherichia coli) as compared to Gram-positive (Staphylococcus aureus) bacteria. The scavenger study reveals that radicals such as O2•- and •OH are responsible for MB and RB mineralization. TOC removal percentages were found to be 96.8 and 98.5% for MB and RB dyes, and experimental data reveal that the Ag-doped BZOP enhances the radical (O2•- and •OH) formation and MB and RB degradation under visible-light irradiation.

Photo-Responsive Ascorbic Acid-Modified Ag2S-ZnS Heteronanostructure Dropping pH to Trigger Synergistic Antibacterial and Bohr Effects for Accelerating Infected Wound Healing

Nonantibiotic approaches must be developed to kill pathogenic bacteria and ensure that clinicians have a means to treat wounds that are infected by multidrug-resistant bacteria. This study prepared matchstick-like Ag2S-ZnS heteronanostructures (HNSs). Their hydrophobic surfactants were then replaced with hydrophilic poly(ethylene glycol) (PEG) and thioglycolic acid (TGA) through the ligand exchange method, and this was followed by ascorbic acid (AA) conjugation with TGA through esterification, yielding well-dispersed PEGylated Ag2S-ZnS@TGA-AA HNSs. The ZnS component of the HNSs has innate semiconductivity, enabling the generation of electron-hole pairs upon irradiation with a light of wavelength 320 nm. These separate charges can react with oxygen and water around the HNSs to produce reactive oxygen species. Moreover, some holes can oxidize the surface-grafted AA to produce protons, decreasing the local pH and resulting in the corrosion of Ag2S, which releases silver ions. In evaluation tests, the PEGylated Ag2S-ZnS@TGA-AA had synergistic antibacterial ability and inhibited Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). Additionally, MRSA-infected wounds treated with a single dose of PEGylated Ag2S-ZnS@TGA-AA HNSs under light exposure healed significantly more quickly than those not treated, a result attributable to the HNSs' excellent antibacterial and Bohr effects.

Bacterial Cellulose-Based Bandages with Integrated Antibacteria and Electrical Stimulation for Advanced Wound Management

Bandages for daily wounds are the most common medical supplies, but there are still ingrained defects in their appearance, comfort, functions, as well as environmental pollution. Here, novel bandages based on bacterial cellulose (BC) membrane for wound monitoring and advanced wound management are developed. The BC membrane is combined with silver nanowires (AgNWs) by using vacuum filtration method to achieve transparent, ultrathin (≈7 µm), breathable (389.98-547.79 g m-2  d-1 ), and sandwich-structured BC/AgNWs bandages with superior mechanical properties (108.45-202.35 MPa), antibacterial activities against Escherichia coli and Staphylococcus aureus, biocompatibility, and conductivity (9.8 × 103 -2.0 × 105  S m-1 ). Significantly, the BC/AgNWs bandage is used in the electrical stimulation (direct current, 600  microamperes for 1 h every other day) treatment of full-thickness skin defect in rats, which obviously promotes wound healing by increasing the secretion of vascular endothelial growth factor (VEGF). The BC bandage is used for monitoring wounds and achieve a high accuracy of 94.7% in classifying wound healing stages of hemostasis, inflammation, proliferation, and remodeling, by using a convolutional neural network. The outcomes of this study not only provide two BC-based bandages as multifunctional wound management, but also demonstrate a new strategy for the development of the next generation of smart bandage.

Construction of durable antibacterial cellulose textiles through grafting dynamic disulfide-containing amino-compound and nanosilver deposition

Cotton textile is very comfortable to wear, and also provides an ideal environment for bacterial propagation, easily causing harm to human health. In order to address this issue, various antibacterial techniques are employed for cotton finishing. However, some processes are complex and involve the use of environmentally unfriendly chemicals. In this work, a durable and efficient antibacterial cotton fabric was prepared via grafting of an amino-compound containing dynamic disulfide bonds, and then in-situ deposition of silver nanoparticles (AgNPs). Briefly, the reactive α-lipoic acid-modified polyethyleneimine (mPEI) was introduced to the cotton fibers via thiol-ene click reaction. Subsequently, the amino groups and dynamically-generated sulfhydryl groups in the mPEI molecules were used to initiate the ultrafast reduction of silver ions without the participation of additional reductant, constructing a stable antibacterial layer on fiber surface. The results reveal that the amino and thiol groups of mPEI could form coordination bonds with the deposited silver nanoparticles, and the antibacterial ability of AgNP@cotton-g-mPEI fabric remains at a high level even after 20 washing cycles. After 30 min of contact with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the antibacterial rates against both bacteria reached 99.99 %. Meanwhile, the network matrix constructed by the recombination of the dynamic disulfide bonds in mPEI endows the cotton fabric with detectable wrinkle resistance and encouraging anti-ultraviolet effect. The present work provides a novel alternative for preparation of durable and efficient antibacterial textiles.

Nano-hydroxyapatite structures for bone regenerative medicine: Cell-material interaction

Bone tissue engineering holds great promise for the regeneration of damaged or severe bone defects. However, several challenges hinder its translation into clinical practice. To address these challenges, interdisciplinary efforts and advances in biomaterials, cell biology, and bioengineering are required. In recent years, nano-hydroxyapatite (nHA)-based scaffolds have emerged as a promising approach for the development of bone regenerative agents. The unique similarity of nHA with minerals found in natural bones promotes remineralization and stimulates bone growth, which are crucial factors for efficient bone regeneration. Moreover, nHA exhibits desirable properties, such as strong chemical interactions with bone and facilitation of tissue growth, without inducing inflammation or toxicity. It also promotes osteoblast survival, adhesion, and proliferation, as well as increasing alkaline phosphatase activity, osteogenic differentiation, and bone-specific gene expression. However, it is important to note that the effect of nHA on osteoblast behavior is dose-dependent, with cytotoxic effects observed at higher doses. Additionally, the particle size of nHA plays a crucial role, with smaller particles having a more significant impact. Therefore, in this review, we highlighted the potential of nHA for improving bone regeneration processes and summarized the available data on bone cell response to nHA-based scaffolds. In addition, an attempt is made to portray the current status of bone tissue engineering using nHA/polymer hybrids and some recent scientific research in the field.

Formulation optimization and evaluation of oromucosal in situ gel loaded with silver nanoparticles prepared by green biosynthesis

Treating oral diseases remains challenging as API is quickly washed out of the application site by saliva turnover and mouth movements. In situ gels are a class of application forms that present sol-gel transition's ability as a response to stimuli. Their tunable properties are provided using smart polymers responsible for stimuli sensitivity, often providing mucoadhesivity. In this study, antimicrobial in situ gels of thermosensitive and pH-sensitive polymers loaded with silver nanoparticles were prepared and evaluated. The nanoparticles were prepared by green synthesis using Agrimonia eupatoria L. extract. According to the data analysis, the in situ gel with the most promising profile contained 15 % of Pluronic® F-127, 0.25 % of methylcellulose, and 0.1 % of Noveon® AA-1. Pluronic® F-127 and methylcellulose significantly increased the viscosity of in situ gels at 37 °C and shear rates similar to speaking and swallowing. At 20 °C, a behavior close to a Newtonian fluid was observed while being easily injectable (injection force 13.455 ± 1.973 N). The viscosity of the formulation increased with temperature and reached 2962.77 ± 63.37 mPa·s (37 °C). A temperature increase led to increased adhesiveness and rigidity of the formulation. The critical sol-gel transition temperature at physiological pH was 32.65 ± 0.35 °C. 96.77 ± 3.26 % of Ag NPs were released by erosion and dissolution of the gel after 40 min. The determination of MIC showed effect against E. coli and S. aureus (0.0625 mM and 0.5000 mM, respectively). The relative inhibition zone diameter of the in situ gel was 73.32 ± 11.06 % compared to gentamicin sulfate. This work discusses the optimization of the formulation of novel antibacterial in situ gel for oromucosal delivery, analyses the impact of the concentration of excipients on the dependent variables, and suggests appropriate evaluation of the formulation in terms of its indication. This study offers a promising dosage form for local treatment of oral diseases.

Emerging strategies for combating Fusobacterium nucleatum in colorectal cancer treatment: Systematic review, improvements and future challenges

Colorectal cancer (CRC) is generally characterized by a high prevalence of Fusobacterium nucleatum (F. nucleatum), a spindle-shaped, Gram-negative anaerobe pathogen derived from the oral cavity. This tumor-resident microorganism has been closely correlated with the occurrence, progression, chemoresistance and immunosuppressive microenvironment of CRC. Furthermore, F. nucleatum can specifically colonize CRC tissues through adhesion on its surface, forming biofilms that are highly resistant to commonly used antibiotics. Accordingly, it is crucial to develop efficacious non-antibiotic approaches to eradicate F. nucleatum and its biofilms for CRC treatment. In recent years, various antimicrobial strategies, such as natural extracts, inorganic chemicals, organic chemicals, polymers, inorganic-organic hybrid materials, bacteriophages, probiotics, and vaccines, have been proposed to combat F. nucleatum and F. nucleatum biofilms. This review summarizes the latest advancements in anti-F. nucleatum research, elucidates the antimicrobial mechanisms employed by these systems, and discusses the benefits and drawbacks of each antimicrobial technology. Additionally, this review also provides an outlook on the antimicrobial specificity, potential clinical implications, challenges, and future improvements of these antimicrobial strategies in the treatment of CRC.

The In Vitro Antibacterial Activity of Argirium SUNc against Most Common Pathogenic and Spoilage Food Bacteria

Foodborne diseases are one of the main issues for human health, and antibacterial packaging plays a major role in food security assurance. Silver ultra nanoparticles (Argirium SUNc) are antimicrobial agents that have a wide spectrum of action, including against pathogenic bacteria and spoilage fungi. The aim of the present study was to evaluate the antibacterial activity of Argirium SUNc on the bacteria most commonly found in food: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium. In this regard, an in vitro study was carried out by assessing the Argirium SUNc effectiveness on different concentrations of each tested microbial strain and at different time intervals. The data showed that the antimicrobial activity of Argirium SUNc was directly related to the microbial concentration and varied depending on the microbial species. Moreover, a greater effectiveness against Gram-negative bacteria than Gram-positive bacteria was observed. These preliminary results provided important information on the silver nanoparticles spectrum of action, and this is an aspect that appears particularly promising for obtaining a viable alternative to traditional antimicrobials to be used against the pathogens and spoilage agents most commonly found in the food chain, harmful both to health and quality aspects.

Antibacterial Activity and Mechanisms of Action of Inorganic Nanoparticles against Foodborne Bacterial Pathogens: A Systematic Review

Foodborne disease outbreaks due to bacterial pathogens and their toxins have become a serious concern for global public health and security. Finding novel antibacterial agents with unique mechanisms of action against the current spoilage and foodborne bacterial pathogens is a central strategy to overcome antibiotic resistance. This study examined the antibacterial activities and mechanisms of action of inorganic nanoparticles (NPs) against foodborne bacterial pathogens. The articles written in English were recovered from registers and databases (PubMed, ScienceDirect, Web of Science, Google Scholar, and Directory of Open Access Journals) and other sources (websites, organizations, and citation searching). "Nanoparticles," "Inorganic Nanoparticles," "Metal Nanoparticles," "Metal-Oxide Nanoparticles," "Antimicrobial Activity," "Antibacterial Activity," "Foodborne Bacterial Pathogens," "Mechanisms of Action," and "Foodborne Diseases" were the search terms used to retrieve the articles. The PRISMA-2020 checklist was applied for the article search strategy, article selection, data extraction, and result reporting for the review process. A total of 27 original research articles were included from a total of 3,575 articles obtained from the different search strategies. All studies demonstrated the antibacterial effectiveness of inorganic NPs and highlighted their different mechanisms of action against foodborne bacterial pathogens. In the present study, small-sized, spherical-shaped, engineered, capped, low-dissolution with water, high-concentration NPs, and in Gram-negative bacterial types had high antibacterial activity as compared to their counterparts. Cell wall interaction and membrane penetration, reactive oxygen species production, DNA damage, and protein synthesis inhibition were some of the generalized mechanisms recognized in the current study. Therefore, this study recommends the proper use of nontoxic inorganic nanoparticle products for food processing industries to ensure the quality and safety of food while minimizing antibiotic resistance among foodborne bacterial pathogens.

Designing of bis-organosilanes as dual chemosensor for Sn(II) and Al(III) ions: Antibacterial activity and in silico molecular docking study

Here, in this article, we present the design and synthesis of 1,2,3-triazole allied Schiff base functionalized organosilanes 6(a-e) utilising single step approach. These compounds were further characterised using NMR (1H, 13C) and mass spectrometry. Furthermore, UV-Visible and fluorescence spectroscopy showed that compound 6a had a high selectivityto Sn(II) and Al(III) metal ions compared to other relevant metal ions with lowlimit of detection (LOD) values. Suppression of -C=N isomerization, constrained intramolecular charge transfer (ICT), and complexation with Sn(II)/Al(III) ions (Chelation Enhanced Fluorescence (CHEF)) results in probe 6a's enhanced turn on fluorescence toward the detection of Sn(II) and Al(III) ions. Probe 6a was a strong candidate for the detection of Sn(II) and Al(III) ions due to its selectivity, reversibility, and competitiveness. Since the detecting phenomenon can be reversed, the sensor 6a perfectly mimics the INHIBIT molecular logic gate. Also, computational study utilising DFT technique was used to shed light on the complexation mode of 6a with Sn(II) and Al(III) metal ions. The compound 6a's antibacterial activity has also been successfully tested against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Additionally, the compound 6a was docked to the E. coli and S. aureus proteins, which exhibited excellent results with binding energies of -7.18 Kcal mol-1 and -7.05 Kcal mol-1, respectively. As both in-vitro and docking studies demonstrated anti-bacterial activity of the probe 6a, it may be anticipated that the probe has potential to serve as anti-bacterial drug in nearly future.

Tailored Coatings for Enhanced Performance of Zinc-Magnesium Alloys in Absorbable Implants

Absorbable metals exhibit potential for next-generation temporary medical implants, dissolving safely in the body during tissue healing and regeneration. Their commercial incorporation could substantially diminish the need for additional surgeries and complications that are tied to permanent devices. Despite extensive research on magnesium (Mg) and iron (Fe), achieving the optimal combination of mechanical properties, biocompatibility, and controlled degradation rate for absorbable implants remains a challenge. Zinc (Zn) and Zn-based alloys emerged as an attractive alternative for absorbable implants, due to favorable combination of in vivo biocompatibility and degradation behavior. Moreover, the development of suitable coatings can enhance their biological characteristics and tailor their degradation process. In this work, four different biodegradable coatings (based on zinc phosphate (ZnP), collagen (Col), and Ag-doped bioactive glass nanoparticles (AgBGNs)) were synthesized by chemical conversion, spin-coating, or a combination of both on Zn-3Mg substrates. This study assessed the impact of the coatings on in vitro degradation behavior, cytocompatibility, and antibacterial activity. The ZnP-coated samples demonstrated controlled weight loss and a decreased corrosion rate over time, maintaining a physiological pH. Extracts from the uncoated, ZnP-coated, and Col-AgBGN-coated samples showed higher cell viability with increasing concentration. Bacterial viability was significantly impaired in all coated samples, particularly in the Col-AgBGN coating. This study showcases the potential of a strategic material-coating combination to effectively tackle multiple challenges encountered in current medical implant technologies by modifying the properties of absorbable metals to tailor patient treatments.

Calotropis procera (L.) mediated synthesis of AgNPs and their application to control leaf spot of Hibiscus rosa-sinensis (L.)

Abstract Nature is gifted with a wide range of ornamental plants, which beautify and clean the nature. Due to its great aesthetic value, there is a need to protect these plants from a variety of biotic and abiotic stresses. Hibiscus rosa-sinensis (L.) is an ornamental plant and it is commonly known as China rose or shoeblack plant. It is affected by several fungal and bacterial pathogens. Current study was designed to isolate leaf spot pathogen of H. rosa-sinensis and its control using silver nanoparticles (AgNPs). Based on molecular and morphological features, the isolated leaf spot pathogen was identified as Aspergillus niger. AgNPs were synthesized in the leaf extract of Calotropis procera and characterized. UV-vis spectral analysis displayed discrete plasmon resonance bands on the surface of synthesized AgNPs, depicting the presence of aromatic amino acids. Fourier transform infrared spectroscopy (FTIR) described the presence of C-O, NH, C-H, and O-H functional groups, which act as stabilizing and reducing molecules. X-ray diffraction (XRD) revealed the average size (~32.43 nm) of AgNPs and scanning electron microscopy (SEM) depicted their spherical nature. In this study, in vitro and in vivo antifungal activity of AgNPs was investigated. In vitro antifungal activity analysis revealed the highest growth inhibition of mycelia (87%) at 1.0 mg/ml concentration of AgNPs. The same concentration of AgNPs tremendously inhibited the spread of disease on infected leaves of H. rosa-sinensis. These results demonstrated significant disease control ability of AgNPs and suggested their use on different ornamental plants.

Silver-integrated EDM processing of TiAl6V4 implant material has antibacterial capacity while optimizing osseointegration

Periprosthetic joint infections (PJI) are a common reason for orthopedic revision surgeries. It has been shown that the silver surface modification of a titanium alloy (Ti-6Al-4V) by PMEDM (powder mixed electrical discharge machining) exhibits an antibacterial effect on Staphylococcus spp. adhesion. Whether the thickness of the silver-modified surface influences the adhesion and proliferation of bacteria as well as the ossification processes and in-vivo antibacterial capacity has not been investigated before. Therefore, the aim of this work is to investigate the antibacterial effect as well as the in vitro ossification process depending on the thickness of PMEDM silver modified surfaces. The attachment of S. aureus on the PMEDM modified surfaces was significantly lower than on comparative control samples, independently of the tested surface properties. Bacterial proliferation, however, was not affected by the silver content in the surface layer. We observed a long-term effect of antibacterial capacity in vitro, as well as in vivo. An induction of ROS, as indicator for oxidative stress, was observed in the bacteria, but not in osteoblast-like cells. No influence on the in vitro osteoblast function was observed, whereas osteoclast formation was drastically reduced on the silver surface. No changes in cell death, the metabolic activity and oxidative stress was measured in osteoblasts. We show that already small amounts of silver exhibit a significant antibacterial capacity while not influencing the osteoblast function. Therefore, PMEDM using silver nano-powder admixed to the dielectric represents a promising technology to shape and concurrently modify implant surfaces to reduce infections while at the same time optimizing bone ingrowth of endoprosthesis.

Antibacterial properties and abrasion-stability: Development of a novel silver-compound material for orthodontic bracket application

PURPOSE

Bacteria-induced white spot lesions are a common side effect of modern orthodontic treatment. Therefore, there is a need for novel orthodontic bracket materials with antibacterial properties that also resist long-term abrasion. The aim of this study was to investigate the abrasion-stable antibacterial properties of a newly developed, thoroughly silver-infiltrated material for orthodontic bracket application in an in situ experiment.

METHODS

To generate the novel material, silver was vacuum-infiltrated into a sintered porous tungsten matrix. A tooth brushing simulation machine was used to perform abrasion equal to 2 years of tooth brushing. The material was characterized by energy dispersive X‑ray (EDX) analysis and roughness measurement. To test for antibacterial properties in situ, individual occlusal splints equipped with specimens were worn intraorally by 12 periodontal healthy patients for 48 h. After fluorescence staining, the quantitative biofilm volume and live/dead distribution of the initial biofilm formation were analyzed by confocal laser scanning microscopy (CLSM).

RESULTS

Silver was infiltrated homogeneously throughout the tungsten matrix. Toothbrush abrasion only slightly reduced the material's thickness similar to conventional stainless steel bracket material and did not alter surface roughness. The new silver-modified material showed significantly reduced biofilm accumulation in situ. The effect was maintained even after abrasion.

CONCLUSION

A promising, novel silver-infiltrated abrasion-stable material for use as orthodontic brackets, which also exhibit strong antibacterial properties on in situ grown oral biofilms, was developed. The strong antibacterial properties were maintained even after surface abrasion simulated with long-term toothbrushing.

Hydrated alginate polysaccharide fabrics grafted with sliver nanocrystals for wearable thermal and health management

The creation of functional components with precise chemistries on carbohydrate polymers is of great significance for future wearable biomedicine and health management. Among various carbohydrate polymers, marine polysaccharide featured with antimicrobial, biodegradable and biocompatible properties is an ideal platform while the water-swelling nature makes it difficult to form stable interface. Here, well-dispersed silver nanoparticles have been in-situ assembled on hydrated alginate fabric (AF), involving chemical absorption of Ag ions and in-situ reduction of conductive Ag layer. Owing to the stable complex formed between Ag ions and carboxyl groups, the Ag-grafted AF exhibits superior Joule heating capability, including low operating voltage (1-3 V), high saturation temperature (63 °C), rapid response time (25 s) and outstanding durability against harsh conditions. Furthermore, the Ag-grafted AF demonstrates noticeable inhibition against E. coli and S. aureus as compared with the pristine AF. This work provides a rational strategy for the functionalization of hydrated polysaccharide and enables wearable thermotherapy devices for human health management.

Antimicrobial mechanism of cuprous oxide (Cu2O) coatings

Some very effective antimicrobial coatings exploit copper or cuprous oxide (Cu2O) as the active agent. The aim of this study is to determine which species is the active antimicrobial - dissolved ions, the Cu2O solid, or reactive oxygen species. Copper ions were leached from Cu2O into various solutions and the leachate tested for both dissolved copper and the efficacy in killing Pseudomonas aeruginosa. The concentration of copper species leached from Cu2O into aqueous solution varied greatly with the composition of the aqueous solution. For a range of solution buffers, killing of P. aeruginosa was highly correlated with the concentration of copper in the leachate. Further, 10 µL bacterial suspension droplets were placed on Cu2O coatings, with or without a polymer barrier layer, and tested for bacterial kill. Killing occurred without contact between bacterium and solid, demonstrating that contact with Cu2O is not necessary. We therefore conclude that soluble copper species are the antimicrobial agent, and that the most potent species is Cu+. The solid quickly raises and sustains the concentration of soluble copper species near the bacterium. Killing via soluble copper ions rather than contact should allow copper coatings to kill bacteria even when fouled, which is an important practical consideration.

The effect of nanosilver-based preparation on microbiological quality of poultry litter

The study aimed to examine an effect of the preparation based on nanosilver suspension on mineral carrier on poultry litter microbiological profile. The study was conducted on Ross 308 broiler chickens. Three groups were formed, 84 birds in each. Preparation used in the study was composed of aqueous nanosilver suspension sprayed on mineral sorbent. Birds were maintained on straw-sawdust litter; the groups were differentiated due to preparation application (C - control without preparation, I - preparation applied once at the beginning, II - preparation added each week). Pooled litter samples were collected from the top layer of the litter (six samplings) in order to determine mesophilic bacteria count. Additionally, on the last day of the experiment litter samples were collected from three points (by drinker, feeder, pen corner) to analyze the total number of microorganisms, Salmonella spp., Escherichia coli, Enterococci, and molds. In the case of mesophilic bacteria count, the highest decrease was noted for group II. Total number of microorganisms determined in various points of the pen did not give clear relationship; in some cases even an increase was found. Salmonella spp. decreased as a result of preparation addition; the highest decrease was noted for samples collected by feeders. The results for Escherichia coli are not unequivocal. However, a decrease was found in the case of drinkers and feeders compared to control, especially in group II. An addition of preparation caused a decrease in Enterococci, especially for samples collected by feeders in group II. Similar tendency was found for molds. The study demonstrated that the preparation exhibits bactericidal properties. However, its effect varies depending on microorganism kind and sample collection point.

The Synergistic Effect of Biosynthesized Silver Nanoparticles and Phytocompound as a Novel Approach to the Elimination of Pathogens

Due to the wide applications of silver nanoparticles (AgNPs), research on their ecological synthesis has been extensive in recent years. In our study, biogenic silver nanoparticles were synthesized extracellularly using the white rot fungus Trametes versicolor via two cultivation methods: static and shaking. The cell filtrate of the fungus was used as a reducing agent in the process of nanoparticle synthesis. Characterization of the obtained nanoparticles was carried out using UV-VIS spectroscopy and scanning electron microscopy. The biosynthesized nanoparticles have antimicrobial potential against pathogenic bacteria, particularly in Gram-negative strains. The bactericidal effect was obtained for E. coli at a concentration of 7 µg/mL. The use of higher concentrations of compounds was necessary for Gram-positive bacteria. Taking into account the problem of the risk of cytotoxicity of AgNPs, combined therapy using a phytochemical was used for the first time, which was aimed at reducing the doses of nanoparticles. The most representative synergistic effect was observed in the treatment of 5 µg/mL silver nanoparticles in combination with 15 µg/mL ursolic acid against E. coli and P. aeruginosa with a bactericidal effect. Moreover, the coadministration of nanoparticles considerably reduced the growth of both Staphylococcus strains, with a bactericidal effect against S. aureus. The viability test confirmed the strong synergistic effect of both tested compounds. Silver nanoparticles synthesized using the T. versicolor showed excellent antibacterial potential, which opens perspectives for future investigations concerning the use of the nanoparticles as antimicrobials in the areas of health.

Study on the antibacterial effect of CuO nanoparticles on Klebsiella pneumonia bacteria: Efficient treatment for colorectal cancer

Colorectal cancer (CRC) is a widespread type of cancer across the world. One efficient therapy approach is the use of antibiotic agents, but one of the main issues related to treating CRC is microbial resistance to antibiotics. As microbes are becoming more resistant to antibiotics and other traditional antimicrobial agents, nanobiotechnology has made it possible to employ nanomaterials with the aim of creating a new generation of antimicrobial agents. In the present study, we have assessed the antimicrobial potential of CuO nanoparticles (NPs) against gram-negative bacteria like Klebsiella pneumoniae carrying PKS genes responsible for encoding colibactin as the key factor for CRC development. For this purpose, the antibacterial effects of conventional antibacterial agents, including erythromycin, piperacillin, and ampicillin, as well as CuONPs, were compared on isolated strains from cancerous candidates. The obtained results revealed that isolates (K. pneumoniae) showed resistance toward the mentioned conventional antibiotics, but CuONPs showed efficient antibacterial properties against K. pneumonia with a MIC = 62 μg/mL. On the other hand, a synergistic antibacterial effect was obtained when CuONPs were used in combination with conventional antibiotics, which are ineffective when used alone. Therefore, CuONPs can be introduced as an excellent antimicrobial agent against K. pneumoniae bacteria in CRC, especially when they are combined with other antibiotics since they can activate the antimicrobial activity of the conventional antibiotics.

Preparation and Characterization of Mono- and Biphasic Ca1-xAgxHPO4·nH2O Compounds for Biomedical Applications

This study aimed to explore the effects of the full-scale replacement (up to 100%) of Ca2+ ions with Ag1+ ions in the structure of brushite (CaHPO4·2H2O). This substitution has potential benefits for producing monophasic and biphasic Ca1-xAgxHPO4·nH2O compounds. To prepare the starting solutions, (NH4)2HPO4, Ca(NO3)2·4H2O, and AgNO3 at different concentrations were used. The results showed that when the Ag/Ca molar ratio was below 0.25, partial substitution of Ca with Ag reduced the size of the unit cell of brushite. As the Ag/Ca molar ratio increased to 4, a compound with both monoclinic CaHPO4·2H2O and cubic nanostructured Ag3PO4 phases formed. There was a nearly linear relationship between the Ag ion ratio in the starting solutions and the wt% precipitation of the Ag3PO4 phase in the resulting compound. Moreover, when the Ag/Ca molar ratio exceeded 4, a single-phase Ag3PO4 compound formed. Hence, adjusting the Ag/Ca ratio in the starting solution allows the production of biomaterials with customized properties. In summary, this study introduces a novel synthesis method for the mono- and biphasic Ca1-xAgxHPO4·nH2O compounds brushite and silver phosphate. The preparation of these phases in a one-pot synthesis with controlled phase composition resulted in the enhancement of existing bone cement formulations by allowing better mixing of the starting ingredients.

Mycosynthesis of silver nanoparticles from endophytic Aspergillus flavipes AUMC 15772: ovat-statistical optimization, characterization and biological activities

BACKGROUND

Mycosynthesis of silver nanoparticles (SNPs) offers a safe, eco-friendly, and promising alternative technique for large-scale manufacturing. Our study might be the first report that uses mycelial filtrate of an endophytic fungus, Aspergillus flavipes, for SNPs production under optimal conditions as an antimicrobial agent against clinical multidrug-resistant (MDR) wound pathogens.

RESULTS

In the present study, among four different endophytic fungi isolated from leaves of Lycium shawii, the only one isolate that has the ability to mycosynthesize SNPs has been identified for the first time as Aspergillus flavipes AUMC 15772 and deposited in Genebank under the accession number OP521771. One variable at a time (OVAT) and Plackett Burman design (PBD) were conducted for enhancing the production of mycosynthesized SNPs (Myco-SNPs) through optimization using five independent variables. The overall optimal variables for increasing the mycosynthesis of SNPs from mycelial filtrate of A. flavipes as a novel endophytic fungus were a silver nitrate concentration of 2 mM, a pH of 7.0, an incubation time of 5 days, and a mycelial filtrate concentration of 30% in dark conditions. UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray spectroscopy (XRD), Transmission electron microscopy (TEM), and Selected-Area Electron Diffraction (SAED) patterns were used to characterize Myco-SNPs, which showed the peak of absorbance at 420 nm, and FTIR showed the bands at 3426.44, 2923.30, 1681.85, 1552.64, and 1023.02 cm-1, respectively, which illustrated the presence of polyphenols, hydroxyl, alkene, nitro compounds, and aliphatic amines, respectively. The XRD pattern revealed the formation of Myco-SNPs with good crystal quality at 2θ = 34.23° and 38.18°. The TEM image and SAED pattern show the spherical crystalline shape of Myco-SNPs with an average size of 6.9232 nm. High antibacterial activity of Myco-SNPs was recorded against MDR wound pathogens as studied by minimum inhibitory concentrations ranging from 8 to 32 µg/mL, time kill kinetics, and post-agent effects. Also, in vitro cell tests indicated that Myco-SNPs support the cell viability of human skin fibroblast cells as a nontoxic compound.

CONCLUSION

The obtained results revealed the successful production of Myco-SNPs using the mycelial filtrate of A. flavipes, which may be a promising nontoxic alternative candidate for combating MDR wound pathogens.

Cu-vitamin B3 donut-like MOFs incorporated into TEMPO-oxidized bacterial cellulose nanofibers for wound healing

In this study, a novel multifunctional nanocomposite wound dressing was developed, consisting of TEMPO-oxidized bacterial cellulose (TOBC) nanofibers functionalized with donut-like copper-based metal-organic frameworks (CuVB3 MOFs). These CuVB3 MOFs were constructed using copper nodes linked by vitamin B3 molecules, resulting in a copper nicotinate crystal structure as confirmed by X-ray diffraction. Electron microscopy confirmed the presence of donut-like microstructures with uniform element distribution in the synthesized MOFs. Through the incorporation of CuVB3 MOFs into the TOBC nanofibers, innovative TOBC-CuVB3 nanocomposites were created. Biocompatibility testing using the MTT assay demonstrated enhanced cell viability of over 115% for the TOBC-CuVB3 nanocomposite. Acridine Orange staining revealed a ratio of 88-92% live cells on the wound dressings. Furthermore, fibroblast cells cultured on TOBC-CuVB3 exhibited expanded morphologies with long filopodia. The agar diffusion method exhibited improved antibacterial activity against both Gram-positive and Gram-negative bacterial strains, correlating with increased CuVB3 concentration in the samples. In vitro cellular scratch assays demonstrated excellent wound healing potential, with a closure rate of over 98% for wounds treated with the TOBC-CuVB3 nanocomposite. These findings underscore the synergistic effects of copper, vitamin B3, and TOBC nanofibers in the wound healing process.

Mechanisms of emerging resistance associated with non-antibiotic antimicrobial agents: a state-of-the-art review

Although the development of resistance by microorganisms to antimicrobial drugs has been recognized as a global public health concern, the contribution of various non-antibiotic antimicrobial agents to the development of antimicrobial resistance (AMR) remains largely neglected. The present review discusses various chemical substances and factors other than typical antibiotics, such as preservatives, disinfectants, biocides, heavy metals and improper chemical sterilization that contribute to the development of AMR. Furthermore, it encompasses the mechanisms like co-resistance and co-selection, horizontal gene transfer, changes in the composition and permeability of cell membrane, efflux pumps, transposons, biofilm formation and enzymatic degradation of antimicrobial chemicals which underlie the development of resistance to various non-antibiotic antimicrobial agents. In addition, the review addresses the resistance-associated changes that develops in microorganisms due to these agents, which ultimately contribute to the development of resistance to antibiotics. In order to prevent the indiscriminate use of chemical substances and create novel therapeutic agents to halt resistance development, a more holistic scientific approach might provide diversified views on crucial factors contributing to the persistence and spread of AMR. The review illustrates the common and less explored mechanisms contributing directly or indirectly to the development of AMR by non-antimicrobial agents that are commonly used.

Nano-delivery systems as a promising therapeutic potential for epilepsy: Current status and future perspectives

Epilepsy is a common chronic neurological disorder caused by aberrant neuronal electrical activity. Antiseizure medications (ASMs) are the first line of treatment for people with epilepsy (PWE). However, their effectiveness may be limited by their inability to cross the blood-brain barrier (BBB), among many other potential underpinnings for drug resistance in epilepsy. Therefore, there is a need to overcome this issue and, hopefully, improve the effectiveness of ASMs. Recently, synthetic nanoparticle-based drug delivery systems have received attention for improving the effectiveness of ASMs due to their ability to cross the BBB. Furthermore, exosomes have emerged as a promising generation of drug delivery systems because of their potential benefits over synthetic nanoparticles. In this narrative review, we focus on various synthetic nanoparticles that have been studied to deliver ASMs. Furthermore, the benefits and limitations of each nano-delivery system have been discussed. Finally, we discuss exosomes as potentially promising delivery tools for treating epilepsy.

A novel ruthenium-silver based antimicrobial potentiates aminoglycoside activity against Pseudomonas aeruginosa

The rapid dissemination of antibiotic resistance combined with the decline in the discovery of novel antibiotics represents a major challenge for infectious disease control that can only be mitigated by investments in novel treatment strategies. Alternative antimicrobials, including silver, have regained interest due to their diverse mechanisms of inhibiting microbial growth. One such example is AGXX, a broad-spectrum antimicrobial that produces highly cytotoxic reactive oxygen species (ROS) to inflict extensive macromolecular damage. Due to the connections identified between ROS production and antibiotic lethality, we hypothesized that AGXX could potentially increase the activity of conventional antibiotics. Using the gram-negative pathogen Pseudomonas aeruginosa, we screened possible synergistic effects of AGXX on several antibiotic classes. We found that the combination of AGXX and aminoglycosides tested at sublethal concentrations led to a rapid exponential decrease in bacterial survival and restored the sensitivity of a kanamycin-resistant strain. ROS production contributes significantly to the bactericidal effects of AGXX/aminoglycoside treatments, which is dependent on oxygen availability and can be reduced by the addition of ROS scavengers. Additionally, P. aeruginosa strains deficient in ROS detoxifying/repair genes were more susceptible to AGXX/aminoglycoside treatment. We further demonstrate that this synergistic interaction was associated with a significant increase in outer and inner membrane permeability, resulting in increased antibiotic influx. Our study also revealed that AGXX/aminoglycoside-mediated killing requires an active proton motive force across the bacterial membrane. Overall, our findings provide an understanding of cellular targets that could be inhibited to increase the activity of conventional antimicrobials. IMPORTANCE The emergence of drug-resistant bacteria coupled with the decline in antibiotic development highlights the need for novel alternatives. Thus, new strategies aimed at repurposing conventional antibiotics have gained significant interest. The necessity of these interventions is evident especially in gram-negative pathogens as they are particularly difficult to treat due to their outer membrane. This study highlights the effectiveness of the antimicrobial AGXX in potentiating aminoglycoside activities against P. aeruginosa. The combination of AGXX and aminoglycosides not only reduces bacterial survival rapidly but also significantly re-sensitizes aminoglycoside-resistant P. aeruginosa strains. In combination with gentamicin, AGXX induces increased endogenous oxidative stress, membrane damage, and iron-sulfur cluster disruption. These findings emphasize AGXX's potential as a route of antibiotic adjuvant development and shed light on potential targets to enhance aminoglycoside activity.

The Impact of Silver Nanoparticle-Induced Photothermal Therapy and Its Augmentation of Hyperthermia on Breast Cancer Cells Harboring Intracellular Bacteria

Breast cancer can harbor intracellular bacteria, which may have an impact on metastasis and therapeutic responses. Silver nanoparticles are FDA-approved for their antimicrobial potential, plus they have pleiotropic benefits for eradicating cancer cells. In the current work we synthesized photothermal silver nanoparticles (AgNPs) with an absorption at 800 nm for heat generation when exposed to near-infrared laser irradiation. Breast cell lines MCF 10A, MCF7, and MDA MB 231 were infected with Pseudomonas aeruginosa, and their response to AgNPs, heat, or photothermal therapy (PTT) was evaluated. The results demonstrate that the application of a brief heating of cells treated with AgNPs offers a synergistic benefit in killing both infected and non-infected cells. Using 10 µg/mL of AgNPs plus laser stimulation induced a temperature change of 12 °C, which was sufficient for reducing non-infected breast cells by 81-94%. Infected breast cells were resistant to PTT, with only a reduction of 45-68%. In the absence of laser stimulation, 10 µg/mL of AgNPs reduced breast cell populations by 10-65% with 24 h of exposure. This concentration had no impact on the survival of planktonic bacteria with or without laser stimulation, although infected breast cells had a 42-90% reduction in intracellular bacteria. Overall, this work highlights the advantages of AgNPs for the generation of heat, and to augment the benefits of heat, in breast cancer cells harboring intracellular infection.