Search

Graphical abstract Abstract The antimicrobial polypeptide ε-poly(l -lysine) (ε-PL) was electrostatically incorporated to poly(acrylic acid) (PAA)/poly(vinyl alcohol) (PVA) electrospun nanofibers. ε-PL loading and distribution was assessed by infrared spectra, ζ-potential measurements and the primary amino reactive dye fluorescamine. Functionalized fibers with 485 ± 140 nm diameter, could be loaded with 0.57–0.74 g ε-PL (g dressing)−1 that released at a constant rate of 5.4 ± 2.8 mg ε-PL (g dressing day)−1. Such a dressings resulted in two orders of magnitude lower bacterial colonization than non-functionalized PAA-PVA after 14 days of incubation. Bacterial impairment was attributed to the damage of cell membranes and the formation of intracellular reactive oxygen species. ε-PL functionalized nanofibers did not display cytotoxicity to human corneal epithelial cells, HCEpC, in 24 h MTT assays. However, the viability of rapidly growing tumoral HeLa cells decreased >50% under the same conditions. The prepared biocompatible nanofibrous dressings with durable antibacterial activity show potential application as wound dressings and other biomedical uses. [ABSTRACT FROM AUTHOR]

The study focuses on antibacterial Cu/C:F nanocomposites deposited onto polyether-ether-ketone (PEEK) substrates. The nanocomposites were prepared by means of physical vapour deposition; copper nanoparticles (NPs), produced with the use of a gas aggregation source, were coated with RF sputtered polytetrafluorethylene. It was found that nanocomposites, formed with a properly tailored number of Cu NPs and C:F barrier thickness, offer a strong antibacterial effect against E. coli without any harm to MG63 cells. [ABSTRACT FROM AUTHOR]

Antibacterial Ag-doped hydroxyapatite/polylactic acid(HA/PLA) composite coatings are rarely studied as implant coatings in recent years. Ag-doped hydroxyapatite (HA) powders were synthesized by chemical precipitation with different initial molar ratios of [Ag]/[Ca] (0(pure HA), 0.001, 0.003 and 0.005), and sintered in air at 800 °C. And then Ag-doped HA/PLA coatings were formed on stainless steel substrates by spin-coating technique for the first time. The obtained products were examined by the techniques of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). The results showed that the doped Ag ions entered the crystal lattice of apatite successfully, but Ag 3 PO 4 was also formed as the initial ratio of [Ag]/[Ca] increased. XPS suggested that some Ag 3 PO 4 was then decomposed into metallic Ag in the high-temperature sintering process. Moreover, the addition of PLA could help form uniform composite coatings. The antibacterial activity of Ag-doped HA powders and Ag-doped HA/PLA composite coatings was also tested and showed a significant antibacterial property (bactericidal efficiency in 24h over 85%) while having low content of Ag. The results indicated both Ag-doped powders and composite coatings would be potential antibacterial materials for future applications. [ABSTRACT FROM AUTHOR]

Cationic dendrimers are intriguing materials that can be used as antibacterial materials; however, they display significant cytotoxicity towards diverse cell lines at high generations or high doses, which limits their applications in biomedical fields. In order to decrease the cytotoxicity, a series of biocompatible hybrid hydrogels based on cationic dendrimers and carboxylated cellulose nanofibrils were easily synthesized by non-covalent self-assembly under physiological conditions without external stimuli. The cationic dendrimers from generation 2 (G2) to generation 4 (G4) based on trimethylolpronane (TMP) and 2,2-bis (methylol)propionic acid (bis-MPA) were synthesized through fluoride promoted esterification chemistry (FPE chemistry). FTIR was used to show the presence of the cationic dendrimers within the hybrid hydrogels, and the distribution of the cationic dendrimers was even verified using elemental analysis of nitrogen content. The hybrid hydrogels formed from G3 and G4 showed 100% killing efficiency towards Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) with bacterial concentrations ranging from 105 CFU/mL to 107 CFU/mL. Remarkably, the hybrid hydrogels also showed good biocompatibility most probably due to the incorporation of the biocompatible CNFs that slowed down the release of the cationic dendrimers from the hybrid hydrogels, hence showing great promise as an antibacterial material for biomedical applications.

Bacterial resistance to antibiotics is one of the biggest problems in the modern world. The prevention of bacterial spreading from hospitals to the community and vice versa is an issue we have to deal with. This review presents a vast potential of contemporary high-pressure techniques in the design of materials with antimicrobial activity. Scientists from all over the world came up with ideas on how to exploit extraordinary properties of supercritical fluids in the production of advantageous materials in an environmentally friendly way. The review summarizes reported methods and results.

A medium chain-length polyhydroxyalkanoate (PHA) was produced by Pseudomonas mendocina CH50 using a cheap carbon substrate, sugarcane molasses. A PHA yield of 14.2% dry cell weight was achieved. Chemical analysis confirmed that the polymer produced was a medium chain-length PHA, a copolymer of 3-hydroxyoctanoate and 3-hydroxydecanoate, P(3HO-co-3HD). Lime oil, an essential oil with known antimicrobial activity, was used as an additive to P(3HO-co-3HD) to confer antibacterial properties to this biodegradable polymer. The incorporation of lime oil induced a slight decrease in crystallinity of P(3HO-co-3HD) films. The antibacterial properties of lime oil were investigated using ISO 20776 against Staphylococcus aureus 6538P and Escherichia coli 8739, showing a higher activity against the Gram-positive bacteria. The higher activity of the oil against S. aureus 6538P defined the higher efficiency of loaded polymer films against this strain. The effect of storage on the antimicrobial properties of the loaded films was investigated. After one-year storage, the content of lime oil in the films decreased, causing a reduction of the antimicrobial activity of the materials produced. However, the films still possessed antibacterial activity against S. aureus 6538P.

Bacillus amyloliquefaciens-9 (GBacillus-9), which is isolated from the intestinal tract of the white-spotted bamboo shark (Chiloscyllium plagiosum), can secrete potential antibacterial materials, such as β-1,3-1,4-glucanase and some antimicrobial peptides. However, the low fermentation production has hindered the development of GBacillus-9 as biological additives. In this study, the Plackett−Burman design and response surface methodology were used to optimize the fermentation conditions in a shake flask to obtain a higher yield and antibacterial activity of GBacillus-9. On the basis of the data from medium screening, M9 medium was selected as the basic medium for fermentation. The data from the single-factor experiment showed that sucrose had the highest antibacterial activity among the 10 carbon sources. The Plackett−Burman design identified sucrose, NH4Cl, and MgSO4 as the major variables altering antibacterial activity. The optimal concentrations of these compounds to enhance antibacterial activity were assessed using the central composite design. Data showed that sucrose, NH4Cl, and MgSO4 had the highest antibacterial activities at concentrations of 64.8, 1.84, and 0.08 g L−1, respectively. The data also showed that the optimal fermentation conditions for the antibacterial material production of GBacillus-9 were as follows: Inoculum volume of 5%, initial pH of 7.0, temperature of 36 °C, rotating speed of 180 rpm, and fermentation time of 10 h. The optimal fermentation medium and conditions achieved to improve the yield of antibacterial materials for GBacillus-9 can enhance the process of developing biological additives derived from GBacillus-9.

In order to endue silk fibroin (SF) sponges with antibacterial function, positively charged poly(hexamethylene biguanide) hydrochloride (PHMB) was incorporated in SF through electrostatic interaction and by freeze-drying technique. The influence of PHMB on the structure and antibacterial activities of SF sponges was investigated. The zeta potential of SF was increased significantly when PHMB was incorporated in SF. The pores with size from 80 to 300 µm and the microscale holes in the pore walls within PHMB-loaded SF sponges provided the channels of PHMB release. The PHMB loaded in the porous sponges showed continuous and slow release for up to 20 days. Effective growth inhibition of both Escherichia coli and Staphylococcus aureus was achieved when the mass ratio of PHMB/SF was higher than 2/100. These results suggest that the porous PHMB/SF sponges have the potential to be used as a novel wound dressing for open skin wounds.

The increase in antibiotic resistance promotes the situation of developing new antibiotics at the forefront, while the development of non-antibiotic pharmaceuticals is equally significant. In the post-antibiotic era, nanomaterials with high antibacterial efficiency and no drug resistance make them attractive candidates for antibacterial materials. Carbon dots (CDs), as a kind of carbon-based zero-dimensional nanomaterial, are attracting much attention for their multifunctional properties. The abundant surface states, tunable photoexcited states, and excellent photo-electron transfer properties make sterilization of CDs feasible and are gradually emerging in the antibacterial field. This review provides comprehensive insights into the recent development of CDs in the antibacterial field. The topics include mechanisms, design, and optimization processes, and their potential practical applications are also highlighted, such as treatment of bacterial infections, against bacterial biofilms, antibacterial surfaces, food preservation, and bacteria imaging and detection. Meanwhile, the challenges and outlook of CDs in the antibacterial field are discussed and proposed., (© 2023 Wiley-VCH GmbH.)

Carbon dots (CDs) correspond to carbon-based materials (CBM) with sizes usually below 10 nm. These nanomaterials exhibit attractive properties such us low toxicity, good stability, and high conductivity, which have promoted their thorough study over the past two decades. The current review describes four types of CDs: carbon quantum dots (CQDs), graphene quantum dots (GQDs), carbon nanodots (CNDs), and carbonized polymers dots (CPDs), together with the state of the art of the main routes for their preparation, either by "top-down" or "bottom-up" approaches. Moreover, among the various usages of CDs within biomedicine, we have focused on their application as a novel class of broad-spectrum antibacterial agents, concretely, owing their photoactivation capability that triggers an enhanced antibacterial property. Our work presents the recent advances in this field addressing CDs, their composites and hybrids, applied as photosensitizers (PS), and photothermal agents (PA) within antibacterial strategies such as photodynamic therapy (PDT), photothermal therapy (PTT), and synchronic PDT/PTT. Furthermore, we discuss the prospects for the possible future development of large-scale preparation of CDs, and the potential for these nanomaterials to be employed in applications to combat other pathogens harmful to human health. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease., (© 2023 Wiley Periodicals LLC.)

Bacterial infection is one of the greatest challenges to public health, requiring new therapeutic methods. Herein, an innovative nanozyme-armed phage (phage@palladium (Pd)) system is fabricated for combating bacterial infection. The proposed phage@Pd preserves the function of the phages to achieve precise recognition and adhesion to the host Escherichia coli. In aid of the phages, the ultrasmall Pd nanozymes equipped with conspicuous pH-dependent peroxidase-like activity can generate toxic hydroxyl radical around the bacteria in acidic and hydrogen-peroxide-overexpressed infection microenvironment while remaining inert in physiological conditions, thus realizing the noteworthy elimination of bacteria at infected sites, and in the meantime ensuring the biological safety of phage@Pd in healthy tissues. In addition, the filamentous structure of phage@Pd can also enhance its bactericidal efficiency toward nonhost bacteria by randomly entangling on them, indicating possible broad-spectrum germicidal efficacy. Notably, phage@Pd can not only eradicate planktonic bacteria, but also kill the bacteria inside the biofilm in vitro. For both in vivo models of acute bacterial pneumonia or subcutaneous abscess, phage@Pd shows significant activity in eliminating infection and promoting tissue recovery. These results demonstrate that the phage@Pd nanohybrid is a safe and effective antimicrobial agent, providing a new insight into development of advanced antibacterial materials., (© 2023 Wiley-VCH GmbH.)

Zinc oxide composite antibacterial materials have attracted much attention due to their excellent anti bacterial activity and wide application potential. In the present paper, the effects of preparation conditions (such as methods, pH, calcination temperature, time, etc.) and particle size of the composite antibacterial materials on the antibacterial properties were reviewed. The classification and antibacterial mechanism of zinc oxide composite antibacterial materials were summarized. Finally, the prospects of zinc oxide composites were discussed. It is hoped that the paper reported here is meaningful for the research of zinc oxide composites. [ABSTRACT FROM AUTHOR]

With the increased risk of disease transmissions and cross-infection caused by microorganisms, the control of microbial infections becomes a very important issue in modern societies. Moreover, with the emergence of antibio-resistant bacterial strains, it is necessary to control the bacterial growth. One of ways to limit the bacterial proliferation is to develop antimicrobial surfaces. The present work describes the synthesis process of a direct linking of propargyled Triclosan to a modified Kraft Pulp. Propargylated Triclosan, and azidated Kraft Pulp were linked in the presence of Cu(I) catalyst, a type of Huisgen’s 1,3-dipolar azide-alkyne cycloaddition reaction, leading to the formation of Triclosan linked to kraft Pulp fibers. The modified Kraft Pulp fibers are characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). This novel material has been investigated for its antibacterial properties against Escherichia coli, Staphylococcus aureus, Bacillus cereus and Pseudomonas aeruginosa. The developed material showed an important antibacterial activity. Although Triclosan is covalently grafted onto Kraft Pulp, its antibacterial properties are maintained. [ABSTRACT FROM AUTHOR]

Abstract: Currently, nanomaterials face a dilemma due to their advantageous properties and potential risks to human health. Here, a strategy to improve both nanomaterial biocompatibility and functionality is established by screening small metabolites from cells as nanomaterial coatings. A metabolomics analysis of cells exposed to nanosilver (nAg) integrates volcano plots (t‐tests and fold change analysis), partial least squares‐discriminant analysis (PLS‐DA), and significance analysis of microarrays (SAM) and identifies six metabolites ( l‐aspartic acid, l‐malic acid, myoinositol, d‐sorbitol, citric acid, and l‐cysteine). The further analysis of cell viability, oxidative stress, and cell apoptosis reveals that d‐sorbitol markedly reduces nAg cytotoxicity. Subsequently, small molecule loading, surface oxidation, and ionic release experiments support d‐sorbitol as the optimal coating for nAg. Importantly, d‐sorbitol loading improves the duration of the antibacterial activity of nAg against Escherichia coli and Staphylococcus aureus. The biocidal persistence of nAg‐sorbitol is extended beyond 9 h, and the biocidal effects at 12 h are significantly higher than those of naked nAg. This work proposes a new strategy to improve the biocompatibility and functionality of nAg simultaneously by screening small metabolites from cells as nanomaterial functional coatings, a method that can be applied to mitigate the side effects of other nanomaterials. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Textile & Apparel / Tekstil ve Konfeksiyon is the property of Tekstil ve Konfeksiyon and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The antibacterial activity against Staphylococcus aureus of aerogels fabricated from colloidal suspensions of chitosan/chondroitin sulfate nanocomplexes is analyzed. Upon freeze-drying the colloidal suspensions, the aerogels presented a porous structure made of microsheets and microfibers. The aerogels could, in addition, be loaded with antimicrobial agents. Loaded with the antibiotic erythromycin, the aerogels showed crystalline deposits, affecting the topography of the samples as well as their mechanical properties, showing a decrease on the apparent Young's modulus and hardness at 40% deformation. Loaded with elephant garlic (Allium ampeloprasum L. var. ampeloprasum) extract, the aerogels showed texturization of the microsheets and microfibers, and the higher relative mass allowed an increase on the apparent Young's modulus and hardness at 40% deformation with respect to pristine aerogels. Unloaded aerogels showed activity against Staphylococcus aureus, including a methicillin-resistant strain. The release of erythromycin from the aerogels to an agar environment is governed by equilibrium forces with the polysaccharides, which allow modulating the load of antibiotic and its concomitant diffusion from the material. The diffusion of the active components of the elephant garlic extract did not show a dependence on the polysaccharide content, revealing a week interaction. The elephant garlic extract resulted active against the methicillin-resistant Staphylococcus aureus strain, while resistance was found for the antibiotic, revealing the therapeutic potential of the natural extract. The antimicrobial aerogels may be used for several therapeutic purposes, such as healing of infected chronic wounds. [ABSTRACT FROM AUTHOR]

Abstract: Pollutants in wastewater include oils, dyes, and bacteria, making wastewater cleanup difficult. Multifunctional wastewater treatment media consisting of poly(ionic liquid)‐grafted polypropylene (PP) nonwoven fabrics (PP@PIL) are prepared by a simple and scalable surface‐grafting process. The fabricated PP@PIL fabrics exhibit impressive switchable oil/water separation (η>99 %) and dye absorption performance (q=410 mg g−1), as well as high antibacterial properties. The oil/water separation can be easily switched by anion exchanging of the PIL segments. Moreover, the multiple functions (oil/water separation, dye absorption, and antibacterial properties) occurred at the same time, and did not interfere with each other. The multifunctional fibrous filter can be easily regenerated by washing with an acid solution, and the absorption capacity is maintained after many recycling tests. These promising features make PIL‐grafted PP nonwoven fabric a potential one‐step treatment for multicomponent wastewater. [ABSTRACT FROM AUTHOR]

In this study, a multilayer antibacterial film was assembled onto 316L stainless steel via mussel-inspired depositions of polydopamine (PDA) and silver (Ag) nanoparticles followed by post-modification with 1H, 1H, 2H, 2H-perfluorodecanethiol. The resulting surface exhibited excellent superhydrophobicity with hierarchical micro/nanostructures that were constructed by both PDA and Ag nanoparticles. The crystal structure and chemical composition of these surfaces were investigated using X-ray photoelectron spectroscopy (XPS) analysis. Potentiodynamic polarization measurements revealed that the corrosion resistance of the as-prepared surfaces were sequentially increased after each step of the fabrication process. Compared with the surface covered with only Ag nanoparticles, the superhydrophobic surfaces exhibited substantially enhanced antibacterial activity against the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus , resulting from the synergistic antibacterial actions of the superhydrophobic surface and Ag nanoparticles. The superhydrophobic surface exhibited lower cytotoxicity, compared to the surface covered with Ag nanoparticles. [ABSTRACT FROM AUTHOR]

This work demonstrated the successful application of N-halamine technology for wound dressings rendered antimicrobial by facile and inexpensive processes. Four N-halamine compounds, which possess different functional groups and chemistry, were synthesized. The N-halamine compounds, which contained oxidative chlorine, the source of antimicrobial activity, were impregnated into or coated onto standard non-antimicrobial wound dressings. N-halamine-employed wound dressings inactivated about 6 to 7 logs of Staphylococcus aureus and Pseudomonas aeruginosa bacteria in brief periods of contact time. Moreover, the N-halamine-modified wound dressings showed superior antimicrobial efficacies when compared to commercially available silver wound dressings. Zone of inhibition tests revealed that there was no significant leaching of the oxidative chlorine from the materials, and inactivation of bacteria occurred by direct contact. Shelf life stability tests showed that the dressings were stable to loss of oxidative chlorine when they were stored for 6 months in dark environmental conditions. They also remained stable under florescent lighting for up to 2 months of storage. They could be stored in opaque packaging to improve their shelf life stabilities. In vitro skin irritation testing was performed using a three-dimensional human reconstructed tissue model (EpiDerm™). No potential skin irritation was observed. In vitro cytocompatibility was also evaluated. These results indicate that N-halamine wound dressings potentially can be employed to prevent infections, while at the same time improving the healing process by eliminating undesired bacterial growth. [ABSTRACT FROM AUTHOR]

A facile and scalable two-step method (including pyrolysis and magnetron sputtering) is created to prepare a core‒shell structured composite consisting of cotton-derived carbon fibers (CDCFs) and nano-copper. Excellent hydrophobicity (water contact angle = 144°) and outstanding antibacterial activity against Escherichia coli and Staphylococcus aureus (antibacterial ratios of >92%) are achieved for the composite owing to the composition transformation from cellulose to carbon and nano-size effects as well as strong oxidizing ability of oxygen reactive radicals from interactions of nano-Cu with sulfhydryl groups of enzymes. Moreover, the core‒shell material with high electrical conductivity induces the interfacial polarization loss and conduction loss, contributing to a high electromagnetic interference (EMI) shielding effectiveness of 29.3 dB. Consequently, this flexible and multi-purpose hybrid of nano-copper/CDCFs may be useful for numerous applications like self-cleaning wall cladding, EMI shielding layer and antibacterial products.

This study underscores the development of Ag hydrogel nanocomposites, as smart substrates for antibacterial uses, via innovative in situ reactive and reduction pathways. To this end, two different synthetic strategies were used. Firstly thiol-acrylate (PSA) based hydrogels were attained via thiol-ene and radical polymerization of polyethylene glycol (PEG) and polycaprolactone (PCL). As a second approach, polyurethane (PU) based hydrogels were achieved by condensation polymerization from diisocyanates and PCL and PEG diols. In fact, these syntheses rendered active three-dimensional (3D) hydrogel matrices which were used as nanoreactors for in situ reduction of AgNO3 to silver nanoparticles. A redox chemistry of stannous catalyst in PU hydrogel yielded spherical AgNPs formation, even at 4 °C in the absence of external reductant and an appropriate thiol-functionalized polymeric network promoted spherical AgNPs well dispersed through PSA hydrogel network, after heating up the swollen hydrogel at 103 °C in the presence of citrate-reductant. Optical and swelling behaviors of both series of hydrogel nanocomposites were investigated as key factors involved in their antimicrobial efficacy over time. Lastly, in vitro antibacterial activity of Ag loaded hydrogels exposed to Pseudomona aeruginosa and Escherichia coli strains indicated a noticeable sustained inhibitory effect, especially for Ag-PU hydrogel nanocomposites with bacterial inhibition growth capabilities up to 120 h cultivation. [ABSTRACT FROM AUTHOR]

The achievement of uniform nanoparticles distribution in polymer matrix is still a major challenge in the design and fabrication of polymer nanocomposites with desired properties. In this paper we propose a novel approach for the preparation of homogeneous polystyrene/silver nanocomposites utilizing Nitroxide Mediated Radical Polymerization (NMRP). In the first step of the developed procedure, the polystyrene grafted silver nanoparticles (Ag@PS) with well-defined core-shell structure and exceptionally high grafting density (from 2 chains/nm 2 to 5.9 chains/nm 2 ) have been synthesized through late injection of nitroxide-coated silver nanoparticles (N-AgNPs) into a TEMPOL mediated styrene polymerization system. Afterwards, the synthesized Ag@PS have been used for the preparation of nanocomposites (PS/Ag@PS) by mixing them with narrow-dispersity polystyrenes and thermoforming at 140 °C. Due to the high flexibility of polymer chains attached to silver surface through nitroxide linker, free volume effect enables interpenetration of polystyrene molecules that provides excellent mutual miscibility of Ag@PS with polymer matrix. The synthesized nanohybrids (Ag@PS) and their nanocomposites (PS/Ag@PS) exhibit effective antibacterial activity with respect to pathogenic bacteria: Pseudomonas aeruginosa (Gram-negative representative) and Staphylococcus aureus (Gram-positive representative). [ABSTRACT FROM AUTHOR]

Eugenol is natural oil that has excellent antibacterial properties but cannot be used to fabricate many products that require thermal processing. One possible alternative to the use of the eugenol molecules in high-temperature processes is the encapsulation of these molecules in a structure that is not toxic and is resistant to thermal treatment. This work investigated the encapsulation process of eugenol molecules in β-cyclodextrine and the antibacterial properties of eugenol-β-cyclodextrine (the eugenol-βCD complex) against Escherichia coli and Staphylococcus aureus . The FTIR, DSC, MEV and TGA results show that the encapsulation method is an excellent alternative to increase the thermal stability of eugenol molecules. A value of 241.32 L.mol − 1 was determined for the formation constant (Kc) of the eugenol-βCD complex, which confirmed the success of the encapsulation process. The MEV analysis shows the formation of approximately 12 μm microcapsules. After the thermal treatment of the eugenol-βCD complex at a temperature of 80 °C for 2 h, the complex retained significant antibacterial action, which confirms the thermal protection of the eugenol molecules. The minimum inhibitory concentration (MIC) and agar diffusion results show that the microcapsules containing 17.08 mmol.L − 1 of eugenol exhibited excellent antibacterial action against Escherichia coli and Staphylococcus aureus after thermal treatment. [ABSTRACT FROM AUTHOR]

This manuscript investigates the effect of silver nanoparticles of different doses and shapes on different gram reaction stain bacteria found in wastewater and to make a comparison between the chemical and physical analyses for some water samples before and after treatment with AgNPs. Two shapes (rod, cube) and four concentrations of 0, 100, 10 and $${1\,\mu{g/ml}}$$ of AgNPs were used on Klebsiella pneumonia, Bacillus cereus and Gardnerella vaginalis. The effect of the interaction between the best AgNPs shape and concentration on tap water inoculated with bacterial species and physical and chemical analyses of water before and after treatment with silver nanoparticles were also investigated. Based on the analysis of variance for growth reduction data for the three bacteria, the models showed significance at $${\alpha = 0.05}$$ . Generally, rod shape with concentration of $${100\, \mu{g/ml}}$$ showed the best reduction results compared to cube-shaped particles with mean values of $${-67.48, -100}$$ and −73.354 for G. vaginalis, B. cereus and K. pneumonia, respectively. Treating tap water inoculated with the bacterial species by silver nanoparticles showed no growth for the bacteria after 1 or 3 days. In general, tap water chemical and physical analyses values before and after treating with AgNPs were increased after treating the sample with AgNPs except for the pH where it shifted from 8.3 to 6.65. However, these values are still within the Saudi maximum limit except the values of turbidity. These results are encouraging for scaling up a treatment process using AgNPs. [ABSTRACT FROM AUTHOR]

Abstract: In the field of micromotors many efforts have been taken to find a substitute for peroxide as fuel. While most approaches turn towards other toxic high energy chemicals such as hydrazine, we introduce here an energy source that is widely used in nature: light. Light is an ideal source of energy and some materials, such as AgCl, have the inherent property to transform light energy for chemical processes, which can be used to achieve propulsion. In the case of silver chloride, one process observed after light exposure is surface modification, which leads to the release of ions, generating chemo‐osmotic gradients. Here we present endeavors to use those processes to propel uniquely shaped micro‐objects of microstar morphology with a high surface‐to‐volume ratio, study their dynamics and present approaches to go towards real environmental applications. [ABSTRACT FROM AUTHOR]

• A new bio-inspired concept for design antibacterial materials. • Spiny particles for concept-proof-investigation had novel antibacterial mechanisms. • Their antibacterial mechanisms reduced possibility of inducing bacterial resistance. • It also showed potential to address the problem of antibiotic resistant bacteria. • The spiny particles did not incur apoptosis or necrosis of MDA-MB-231 cells. Bacterial resistance induced by antibacterial nanomaterials alert us that winning the arms race between bacteria and antibacterial agents requires new ideas. We provide a proof-of-concept investigation into mimicking competitive interactions in ecosystems to control bacteria contamination. Competitors in ecosystems can have similar geometry scale and gain advantages via strategies such as physical killing and nutrient competition. Antibacterial materials can be designed to mimic these competitive strategies to address the problem of bacterial resistance induced by nanomaterials. Herein, we tune the morphology of spiny particles (NH 2 -MIL-101(Al) MOFs) to prove our concept. Their mechano-bactericidal activity was proved in this work, they also competed nutrients with bacteria and did not leach antibacterial chemicals to the microenvironment. This material showed potential to prevent inducing bacterial resistance over time as demonstrated in this work. Furthermore, the biocompatibility was tested in vitro using MDA-MB-231 cells, the particles can be engulfed into the cells without inducing necrosis or apoptosis. This work demonstrated the feasibility of mimicking the competitive interactions by biomimetic materials to reduce bacterial resistance. [ABSTRACT FROM AUTHOR]

Currently, the global COVID-19 pandemic has significantly increased the public attention toward the spread of pathogenic viruses and bacteria on various high-frequency touch surfaces. Developing a self-disinfecting coating on a touchscreen is an urgent and meaningful task. Superlattice materials are among the most promising photocatalysts owing to their efficient charge transfer in abundant heterointerfaces. However, excess electronic defects at the heterointerfaces result in the loss of substantial amounts of photogenerated charge carrier. In this study, a ZnOFe 2 O 3 superlattice nanofilm is designed via atomic layer deposition for photocatalytic bactericidal and virucidal touchscreen. Additionally, electronic defects in the superlattice heterointerface are engineered. Photogenerated electrons and holes will be rapidly separated and transferred into ZnO and Fe 2 O 3 across the heterointerfaces owing to the formation of ZnO, FeO, and ZnFe covalent bonds at the heterointerfaces, where ZnO and Fe 2 O 3 function as electronic donors and receptors, respectively. The high generation capacity of reactive oxygen species results in a high antibacterial and antiviral efficacy (>90%) even against drug-resistant bacteria and H1N1 viruses under simulated solar or low-power LED light irradiation. Meanwhile, this superlattice nanofilm on a touchscreen shows excellent light transmission (>90%), abrasion resistance (10 6 times the round-trip friction), and biocompatibility., (© 2023 Wiley-VCH GmbH.)

Infection prevention and bone-implant integration remain major clinical challenges. Silver nanoparticle (AgNPs) bone-implant coatings have received extensive attention. Balancing the toxicity and antibacterial properties of AgNP coatings has become a significant problem. In this study, inspired by the structure of the ant-nest, a polyetherimide (PEI) coating with ant-nest structure was prepared, aiming to realize the structural modification of the AgNPs coating. AgNPs were loaded in the inner porous area of the PEI ant-nest coating, avoiding direct contact between AgNPs and cells. The nanopores on the surface of the coating ensured the orderly release of silver ions. SEM, FTIR, XPS, and XRD experiments confirmed that the PEI ant-nest coating was successfully prepared. Interestingly, in the PEI ant-nest coating, Ag + showed a steady increase in the release trend within 28 days, and there was no early burst release phenomenon. In -vivo experiments showed a good control effect for local infection. In order to improve the osteogenic properties of the materials, 45S5 bioactive glasses (BG) were loaded to achieve further osseointegration. In general, this natural ant-nest-inspired surface modification coating for orthopedic prostheses provides a new strategy for balancing the antibacterial and toxic effects of AgNP coatings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Catalytic therapy can concurrently enhance therapeutic efficacy and decrease side effects by converting less toxic or nontoxic endogenous substances into various highly toxic reactive species (e.g., toxic radicals) to induce cell apoptosis/necrosis, which has been exploited to combat different types of diseases. As material science and nanotechnology evolve for application in disease therapies, a variety of catalytic biomaterials and nanomedicines have been elaborately designed and synthesized to mediate catalytic reactions and/or enhance the corresponding catalytic treatment efficacy. This review systematically summarizes, outlines, and discusses the state-of-the-art advances in the development and use of catalytic biomaterials and nanomedicines in diverse biomedical applications, particularly concentrating on their endogenous activators, exogenous stimuli (e.g., light, heat, ultrasound, and magnetic field), and the integration of endogenous and exogenous triggers to improve the efficacy of biomaterial/nanomedicine-enabled catalytic treatments. The biosafety and biocompatibility of various catalytic biomaterials and nanomedicines for biomedical applications are also discussed. Finally, the current challenges and future opportunities for advancement of catalytic biomaterials and nanomedicines are highlighted, aiming to boost their early fulfillment of practical clinical applications., (© 2022 Wiley-VCH GmbH.)

Reactive oxygen species (ROS) are favorable for antibacterial infection but their overproduction results in serious inflammatory response and aggravates the hypoxic state of the wound tissue, which is detrimental to healing stages of proliferation and remodeling. Here, an atomic-dispersion Fe-doped oxygen-deficient molybdenum oxide MoO 3- X (ADFM) bifunctional nanozyme, featuring implanted peroxidase-like and enhanced catalase-like activity, is developed for decomposing H 2 O 2 into strongly oxidizing hydroxyl radicals (•OH) for prevention of bacterial infection and into plentiful O 2 for healing stages. Therein, the introduction of Fe into MoO 3- X primarily produces an asymmetric electron density difference by elongating the bond length between metal atoms, synchronously stabilizing adsorption of •OH and weakening the adsorption of O 2 . ADFM also shows unimaginably high aqueous dispersity and pH-adaptive ROS regulation in the wound microenvironment, both of which are favorable for ADFM to fully exert enzyme-like activity for timely antibacterial and efficient wound-healing action. ADFM thus achieves efficient healing of drug-resistant bacteria-infected wounds in vivo, at an ultralow dosage of 30 µg mL -1 against 10 6 CFU mL -1 extended spectrum β-lactamases-producing Escherichia coli, exhibiting a wound-healing efficiency of ≈10 mm 2 per day, which sets a benchmark among these noble-metal-free nanozyme-based wound-healing agents., (© 2023 Wiley-VCH GmbH.)

Development and production of antibacterial materials were gained momentum because of the increasing infectional diseases in recent years. Antibacterial products are used in many industries, such as, textile, dye and package industries and medical technology. Short duration antibacterial affect is the main problem for these products. Therefore, the development of materials that exhibit long duration antimicrobial activity, is needed for industry. In this study, the free carboxylic acid groups of alginate were activated using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and amoxicillin (AMX) was covalently immobilized to alginate. AMX, D-α-amino- p -hydroxybenzyl penicillin trihydrate, is one of the most frequently used β-lactam antibiotics that has been employed to treat and reduce the spread of bacterial infections in human, with the benefits of maintaining animal welfare. At the end of the study, an antibacterial biomaterial was developed. The optimum reaction medium, that immobilization of AMX to Ca-alginate beads, was determined as; 1 mg of EDC, pH 5, 50 mM of phosphate buffer, 5 pieces of Ca-alginate beads, incubation temperature was 4 °C, mixing speed was 150 rpm, initial amount of AMX (IAA) was 4 mg and incubation time 1.5 h. Ca-alginate beads and AMX immobilized Ca-alginate beads were tested for antibacterial affects against Escherichia coli (ATCC 8739, gram negative) and Staphylococcus aureus (ATCC 6538, gram positive) bacterial strain. According to the SEM images and ATR-FTIR spectrums of AMX immobilized Ca-alginate and Ca-alginate beads were analyzed, the immobilization process was proved successfully. Developed biomaterial was antibacterial according to antibacterial tests. [ABSTRACT FROM AUTHOR]

In this study, carbon activation was carried out on corncobs at 700 °C using H 3 PO 4 chemical activation method. While silver coating activated carbons, a reduction procedure with hydrazine was used. The crystal characteristics of the obtained activated carbon and silver coated activated carbon (AC/Ag) were characterized using X-ray diffraction (XRD), structural characteristics were characterized via Fourier transform electron infrared spectroscopy FTIR. The surface morphology was characterized using scanning electron microscope (SEM) and the specific surface area was characterized using Brunauer-Emmett-Teller theory (BET). The BET surface area of the activated carbon produced was determined as 970.38 m 2 /g at a temperature of 700 °C after the 24 h of impregnation time and in the activated carbon obtained from a 1:2 impregnation ratio. It is clearly visible in the SEM photographs that silver ions are substantially coated on activated carbons. The Ag content and surface morphology of the AC/Ag composites related to the initial concentration of AgNO 3. The higher the Ag content caused the smaller the specific surface area on the AC. The antibacterial effects of characterized composites were also determined to be effective against Escherichia coli ( E. coli ). A higher antibacterial activity of the AC/Ag composite powders was discovered to be also effective against Escherichia coli . The material could be used for the prevention of microbial contamination in different areas. [ABSTRACT FROM AUTHOR]

Increasing evidence has emphasized the pivotal role of antibiotic tolerance in the evolution of antibiotic resistance, refractory infection and infection recurrence. Moreover, satisfactory treatment of infection relies highly on early, precise detection and subsequent timely therapeutic interventions. In this study, the phenotype of increased production of H 2 S in antibiotic-tolerant Staphylococcus aureus (S. aureus) was identified and proven to be essential to the maintenance of antibiotic tolerance. Hence, a photoacoustic probe for detecting infection as well as an antibiotic enhancer targeting bacterial endogenous H 2 S to eradicate antibiotic-tolerant bacteria was successfully developed based on a bismuth metal-organic framework (Bi-MOF). Bi-MOF achieved early in situ and precise photoacoustic imaging of infection by generating Bi 2 S 3 inside bacteria. Moreover, Bi-MOF enhanced the eradication efficacy of methicillin against tolerant S. aureus by downregulating the intracellular H 2 S levels. Overall, Bi-MOF offers a promising diagnostic tool for early, precise infection diagnosis and a therapeutic strategy for tolerant bacteria-related refractory infection. [Display omitted] • Bi-MOF breaks down the antibiotic-tolerance by targeting endogenous H 2 S. • Bi-MOF realizes in-situ photoacoustic imaging diagnosis by precipitating bacterial H 2 S. • Multi-omics analysis reveals the metabolic mobolization and proteotoxicity effects of the Bi-MOF. • Bi-MOF cooperates with methicillin to prevent the recurrence of tolerant S. aureus -related infection. • Antibiotic-tolerant S. aureus upregulates H 2 S production to defend against antibiotics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diglycolic acid is firstly installed into PBT backbone. • PBDTs show good mechanical properties with high elongation at break and strength. • PBDTs behave improved degradability in bio/seawater degradation. • PBDT50 exhibited the fastest degradation among reported marine degradable polymers. • Modified with traces of Ag@AgCl, PBDTs obtain enhanced antibacterial activity. Marine plastic pollution is a worldwide challenge making new progress in the field of degradable polymers necessary. However, it is difficult for commercial biodegradable polymers, such as polylactide (PLA), to realize rapid degradation in seawater by simply blending modification. Here, we prepared a novel series of poly(butylene diglycolate/terephthalate) (PBDT) copolymers by introducing diglycolic acid into PBT. The proposed polyesters can serve as an eco-friendly substitute for existing packaging materials. The mechanical property of PBDTs, with high tensile strength (>23.4 MPa) and elastic modulus (95–610 MPa), had advantages compared with commercial degradable polymers. The hydrophilicity is enhanced with ether bonds of butylene diglycolate (BD) segments. And the hydrolysis of copolymers was accelerated in seawater, showing 16% weight loss after 30 days. Moreover, PBDTs with BD segments ≥ 20% performed great degradability in Phosphate Buffered Saline and enzymatic solution. And their degradation mechanism was monitored through various tests such as 1H NMR, SEM and GPC. With a small number of antibacterial agents, such as 8% mass fraction of chitosan nanoparticles (CHNPs) or 1.0% of Ag@AgCl, PBDT composites could obtain good antibacterial ability for Gram-negative Escherichia coli without sacrificing the thermal, mechanical properties of the parent PBDT50. This work provides insights and direction for the development of seawater degradable polymers and thereby is able to relieve additional marine pollution in the future. [ABSTRACT FROM AUTHOR]

For the design of antibacterial materials comprising hybrid silica-containing plant oils capable of performing a controlled release of essential oil components, tests of lemongrass, citronella, basil, rosemary, eucalyptus, tea tree, lavender, clove and cinnamon against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Micrococcus luteus showed the essential oil of cinnamon to have the greatest antimicrobial activity. Hybrid organic-inorganic silica materials functionalized with methyl groups (methyl/Si, molar proportions 0.04-1.00), prepared with a sol-gel method, served as host matrices for the essential oil of cinnamon. The antibacterial and release properties of this oil in hybrid silicas were tested with disk diffusion experiments on bacterial cultures. The methyl-silica material with methyl/Si molar ratio 0.75 and load 7.5 % by mass of the encapsulated cinnamon essential oil presented adequate mechanical stability and maintained antibacterial properties for a prolonged period. This work has produced the first application of hybrid organic-inorganic silicas containing an essential oil for the design of antibacterial materials. Graphical Abstract: [ABSTRACT FROM AUTHOR]

The objective of this study was to answer the following question: are quaternary ammonium antibacterials suitable for dental materials? Reviewing the literature on quaternary ammonium compounds evidenced that this type of compounds is soluble in water. Our own findings also showed that they are well soluble in water and that their application as dental composites requires to check their solubility level in water. [ABSTRACT FROM AUTHOR]

Various carbon chain linkages were introduced during the process of synthesizing silver-nanoparticles (AgNPs)-decorated graphene nanocomposites [referred to as GO- C x -Ag where, HS-(CH 2 ) x -SH = C x and x = 0, 2, or 4] to evaluate antibacterial properties. The nano-structures of GO- C x -Ag were characterized using TEM and XPS, revealing that GO- C 2 -Ag comprises well-dispersed and smaller AgNPs anchored onto the surface of graphene sheets than the GO- C 0 -Ag and GO- C 4 -Ag. The antibacterial activities of those nanocomposites were assessed using paper-disk diffusion and minimal inhibitory concentration (MIC) methods against Gram-negative and Gram-positive bacteria. The results showed that carbon chain linkers enhanced the antibacterial activity against Gram-negative Salmonella typhimurium and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus . In particular, GO- C 2 -Ag showed higher antibacterial activity than GO- C 0 -Ag and GO- C 4 -Ag due to nearly eight times higher reactive oxygen species (ROS) formation which determined by fluorescence-based ROS detection experiment. Also, LC-inductively coupled plasma mass spectrometer (LC-ICP-MS) demonstrated that the Ag release from GO- C x -Ag was insignificant (0.03%). However, the higher ROS formation from GO- C 2 -Ag was facilitated by higher dispersion, smaller size, and well attachment of AgNPs with AgO species onto graphene sheets. These results suggest that the medium length carbon chain linkers in between Ag and GO can be utilized to improve antibacterial activity. [ABSTRACT FROM AUTHOR]

This work demonstrated the successful application of N-halamine technology for wound dressings rendered antimicrobial by facile and inexpensive processes. Four N-halamine compounds, which possess different functional groups and chemistry, were synthesized. The N-halamine compounds, which contained oxidative chlorine, the source of antimicrobial activity, were impregnated into or coated onto standard non-antimicrobial wound dressings. N-halamine-employed wound dressings inactivated about 6 to 7 logs of Staphylococcus aureus and Pseudomonas aeruginosa bacteria in brief periods of contact time. Moreover, the N-halamine-modified wound dressings showed superior antimicrobial efficacies when compared to commercially available silver wound dressings. Zone of inhibition tests revealed that there was no significant leaching of the oxidative chlorine from the materials, and inactivation of bacteria occurred by direct contact. Shelf life stability tests showed that the dressings were stable to loss of oxidative chlorine when they were stored for 6 months in dark environmental conditions. They also remained stable under florescent lighting for up to 2 months of storage. They could be stored in opaque packaging to improve their shelf life stabilities. In vitro skin irritation testing was performed using a three-dimensional human reconstructed tissue model (EpiDerm™). No potential skin irritation was observed. In vitro cytocompatibility was also evaluated. These results indicate that N-halamine wound dressings potentially can be employed to prevent infections, while at the same time improving the healing process by eliminating undesired bacterial growth.

This study underscores the development of Ag hydrogel nanocomposites, as smart substrates for antibacterial uses, via innovative in situ reactive and reduction pathways. To this end, two different synthetic strategies were used. Firstly thiol-acrylate (PSA) based hydrogels were attained via thiol-ene and radical polymerization of polyethylene glycol (PEG) and polycaprolactone (PCL). As a second approach, polyurethane (PU) based hydrogels were achieved by condensation polymerization from diisocyanates and PCL and PEG diols. In fact, these syntheses rendered active three-dimensional (3D) hydrogel matrices which were used as nanoreactors for in situ reduction of AgNO3 to silver nanoparticles. A redox chemistry of stannous catalyst in PU hydrogel yielded spherical AgNPs formation, even at 4 °C in the absence of external reductant; and an appropriate thiol-functionalized polymeric network promoted spherical AgNPs well dispersed through PSA hydrogel network, after heating up the swollen hydrogel at 103 °C in the presence of citrate-reductant. Optical and swelling behaviors of both series of hydrogel nanocomposites were investigated as key factors involved in their antimicrobial efficacy over time. Lastly, in vitro antibacterial activity of Ag loaded hydrogels exposed to Pseudomona aeruginosa and Escherichia coli strains indicated a noticeable sustained inhibitory effect, especially for Ag–PU hydrogel nanocomposites with bacterial inhibition growth capabilities up to 120 h cultivation.