Search

Abstract It is of great significance to develop a novel approach to treat bacterial infections, as the frequent misuse of antibiotics leads to the serious problem of bacterial resistance. This study proposed antibiotic-free antibacterial nanoparticles for eliminating methicillin-resistant Staphylococcus aureus (MRSA) based on a multi-model synergistic antibacterial ability of chemodynamic therapy (CDT), photothermal effect, and innate immunomodulation. Specifically, a polydopamine (PDA) layer coated and Ag nanoparticles loaded core-shell structure Fe3O4 nanoparticles (Fe3O4@PDA-Ag) is prepared. The Fe3O4 catalyzes H2O2 present in acidic microenvironment of bacterial infection into more toxic reactive oxygen species (ROS) and synergizes with the released Ag ions to exert a stronger bactericidal capacity, which can be augmented by photothermal action of PDA triggered by near-infrared light and loosen the biofilm by photothermal action to promote the penetration of ROS and Ag ion into the biofilm, result in disrupting biofilm structure along with killing encapsulated bacteria. Furthermore, Fe3O4@PDA-Ag exerts indirect antibacterial effects by promoting M1 macrophage polarizing. Animal models demonstrated that Fe3O4@PDA-Ag effectively controlled MRSA-induced infections through photothermal enhanced CDT, Ag+ releasing, and macrophage-mediated bactericidal properties. The acid-triggered antibacterial nanoparticles are expected to combat drug-resistant bacteria infection. Graphical abstract

In this study, a SiO2 support was modified with zinc and cerium to obtain a material with excellent antibacterial properties. The optimal preparation conditions resulting in the highest antibacterial efficiency (cZn = 0.83 M, cCe = 0.005 M, reaction time = 1.6 h) were identified by applying response surface methodology. The antibacterial experiments were carried out based on the coating plate method using Escherichia coli. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analyses revealed an evenly distributed composition with a lamellar structure in the samples. Further analysis through X-ray photoelectron spectroscopy (XPS) indicated that zinc and cerium were successfully modified onto the silica carriers in the form of oxides. The high percentage of Ce4+/Ce3+ ions promotes an increase in anti-inflammatory cytokines and a decrease in pro-inflammatory cytokines, thereby enhancing antimicrobial properties. The detection of ion dissolution and specific surface area and particle size explained that the addition of cerium promoted the loading and release of antimicrobial zinc ions. The introduction of cerium into the ZnO lattice results in the replacement of zinc atomic sites with cerium atomic sites. This substitution causes disorganization in the arrangement of zinc ions in certain regions, leading to a weakening of the Zn–O bond and an increased release of zinc ions. The content of zinc ions increased from 1.06% to 1.79%, which increased the specific surface area of the composites from 214.50803 m2/g to 308.86977 m2/g, which gave the materials high adsorption properties, thus improving their antimicrobial performance. Combined with the positive synergistic effect factor and synergistic coefficient of 1.89 calculated by the response surface method, it was observed that a notable synergistic effect exists between zinc and cerium. [ABSTRACT FROM AUTHOR]

It is of great significance to develop a novel approach to treat bacterial infections, as the frequent misuse of antibiotics leads to the serious problem of bacterial resistance. This study proposed antibiotic-free antibacterial nanoparticles for eliminating methicillin-resistant Staphylococcus aureus (MRSA) based on a multi-model synergistic antibacterial ability of chemodynamic therapy (CDT), photothermal effect, and innate immunomodulation. Specifically, a polydopamine (PDA) layer coated and Ag nanoparticles loaded core-shell structure Fe3O4 nanoparticles (Fe3O4@PDA-Ag) is prepared. The Fe3O4 catalyzes H2O2 present in acidic microenvironment of bacterial infection into more toxic reactive oxygen species (ROS) and synergizes with the released Ag ions to exert a stronger bactericidal capacity, which can be augmented by photothermal action of PDA triggered by near-infrared light and loosen the biofilm by photothermal action to promote the penetration of ROS and Ag ion into the biofilm, result in disrupting biofilm structure along with killing encapsulated bacteria. Furthermore, Fe3O4@PDA-Ag exerts indirect antibacterial effects by promoting M1 macrophage polarizing. Animal models demonstrated that Fe3O4@PDA-Ag effectively controlled MRSA-induced infections through photothermal enhanced CDT, Ag+ releasing, and macrophage-mediated bactericidal properties. The acid-triggered antibacterial nanoparticles are expected to combat drug-resistant bacteria infection. [ABSTRACT FROM AUTHOR]

The problem of antibiotic misuse leading to bacterial resistance is a significant challenge currently faced. The rapid adaptability and evolutionary capabilities of microorganisms have caused strains that were initially sensitive to antibiotics to gradually become resistant, posing a threat to traditional antibacterial treatments. Therefore, the search for antibacterial treatment methods, especially those less likely to induce resistance, has become crucial. Photodynamic antibacterial therapy is an emerging method with efficient antibacterial and selective effects, reducing the risk of resistance. A two-dimensional nanocomposite material, modified with quaternized ruthenium complexes on MXene, has been developed. The minimum inhibitory concentrations against Escherichia coli and Staphylococcus aureus were found to be 23.4 and 29.0 μg/mL, respectively, under xenon lamp irradiation with a light power intensity of 100 mW/cm² for 20 min. The bactericidal effects of the Q/Ru-MXene composite system were quantitatively and qualitatively confirmed through plate counting and live/dead staining. This system integrates the chemical antibacterial properties of quaternary ammonium salts, the photodynamic antibacterial effects of ruthenium complexes, and the photothermal antibacterial properties of MXene. The simultaneous application of these three therapeutic approaches allows for the development of a chemical/photodynamic/photothermal antibacterial strategy that can attack bacteria on multiple levels, enhancing treatment efficacy, slowing down the development of bacterial resistance, and adapting better to different types of infections. Research and the application of this comprehensive strategy have the potential to bring breakthroughs and innovations to the field of antibacterial treatment. [ABSTRACT FROM AUTHOR]

Single-atom catalysts based on carbon-based materials have a high catalytic activity and excellent photothermal performance. In this article, iron single-atom catalysts loaded on C-MOF-5 carriers have been prepared for the application of photothermal catalytic antimicrobial therapy. Iron single-atom catalysts (Fe SACs) exhibit significant peroxidase-like catalytic activity and catalyze the production of large amounts of hydroxyl radicals (·OH) when hydrogen peroxide is present, which have a killing effect on bacteria. In addition, the excellent photothermal properties of the carbon material allow Fe SACs to rapidly generate a localized high temperature under NIR-II laser light (1064 nm) to kill bacteria and enhance peroxidase-like catalytic activity to produce a large number of hydroxyl radicals. In vitro bacterial assays demonstrated that the synergistic antimicrobial strategy of chemodynamic therapy (CDT) and photothermal therapy (PTT) is nearly 100% effective against E. coli and S. aureus, demonstrating greater antimicrobial efficiency than chemodynamic therapy and photothermal therapy alone. In vivo bacterial assay shows better wound healing in mice treated with CDT, PTT synergistic antimicrobial therapy. In summary, these carbon-based single-atom catalysts could be used as antimicrobial agents through the CDT and PTT synergistic antimicrobial effect. [ABSTRACT FROM AUTHOR]

In this study, the antibacterial effects of six plant essential oils against four common bacteria in the vapor phase was investigated by plate fumigation method with the measurement of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The combination of essential oils with better bactericidal effect was studied and applied to keep fresh of capsicum frutescens. The antibacterial mechanism of cinnamon essential oil against Escherichia coli (E. coli) was also determined by transmission electron microscopy (TEM) and electric conductivity. The results showed that citronella essential oil, cinnamon essential oil and basil essential oil had more significant antibacterial effect, which could inhibit all tested bacteria at the concentration of 0.125 μL/mL. Citronella essential oil and cinnamon essential oil had better bactericidal effect, which could kill all the tested bacteria except Pseudomonas aeruginosa at the concentration of 0.125 μL/mL. Blended essential oils with the ratio of citronella essential oil, cinnamon essential oil and basil essential oil being 4:1:8, demonstrated the best antibacterial activity. The blended essential oils showed synergistic effects on E. coli and Salmonella, but antagonistic effect on Staphylococcus aureues. GC-MS indicated that the antibacterial ability of citronella essential oil mainly came from citronellal, geraniol and citronellol, cinnamon essential oil came from cinnamaldehyde and basil essential oil came from estragole and linalool. The application of blended essential oil in modified atmosphere preservation of capsicum frutescens had a better preservative and fresh-keeping effects when the spatial concentration of blended essential oil was 0.125 μL/mL. TEM showed morphological changes and cell membrane shrinkage of E. coli after fumigation with cinnamon essential oil. The conductivity test showed that the membrane permeability of E. coli increased after fumigation, which resulted in electrolyte leakage. In conclusion, the possible antibacterial mechanism of vapor-phase cinnamon essential oil against E. coli is to change the cell morphology and membrane permeability.

Drug-resistant bacteria and infectious diseases associated with biofilms pose a significant global health threat. The integration and advancement of nanotechnology in antibacterial research offer a promising avenue to combat bacterial resistance. Nanomaterials possess numerous advantages, such as customizable designs, adjustable shapes and sizes, and the ability to synergistically utilize multiple active components, allowing for precise targeting based on specific microenvironmental variations. They serve as a promising alternative to antibiotics with diverse medical applications. Here, we discuss the formation of bacterial resistance and antibacterial strategies, and focuses on utilizing the distinctive physicochemical properties of nanomaterials to achieve inherent antibacterial effects by investigating the mechanisms of bacterial resistance. Additionally, we discuss the advancements in developing intelligent nanoscale antibacterial agents that exhibit responsiveness to both endogenous and exogenous responsive stimuli. These nanomaterials hold potential for enhanced antibacterial efficacy by utilizing stimuli such as pH, temperature, light, or ultrasound. Finally, we provide a comprehensive outlook on the existing challenges and future clinical prospects, offering valuable insights for the development of safer and more effective antibacterial nanomaterials. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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.)

Bacterial infections represent one of the serious human healthcare threats, and ≈80% of bacterial infections are related to biofilm. So far, there are extensive investigations on the development of robust biomaterials toward the elimination of biofilms and synergistic antibacterial applications. Despite the progress made, concerns have always been raised regarding the sophisticated synthesis and pre‐modification of hybrid materials, complicated purification and high‐cost work. In this study, a series of robust and integrative nanoparticles (NPs) assembled from two types of natural building blocks (natural polyphenols and tobramycin antibiotics) is successfully fabricated via a one‐pot integration approach, which can efficiently destruct the biofilm structure and kill bacteria via enhanced antibiotic infiltration. Notably, natural polyphenols and tobramycin can release from the formed NPs in an on‐demand manner in the bacterial‐induced environment. The former ones can inhibit quorum sensing within bacteria through competitive combination with autoinducer‐2 (AI‐2) to remove the existing biofilm, and the latter antibiotics exert high antibacterial activity both in vitro and in vivo. This study provides new inspirations toward robust and synergistic antimicrobial and antibiofilm nanomaterials via the facile integration of naturally occurring molecules. [ABSTRACT FROM AUTHOR]

[Display omitted] Titanium (Ti) was an excellent medical metal material, but the lack of good antibacterial activity confined its further practical application. To solve this dilemma, a coating containing graphene oxide (GO) and copper (Cu) was prepared on the surface of Ti sheet (Ti/APS/GO/Cu). First, physical sterilization could be carried out through the sharp-edged sheet structure of GO. Second, the oxygen-containing functional group on the surface of GO and the released Cu2+ would generate reactive oxygen species for chemical sterilization. The synergistic effect of GO and Cu substantially enhanced the in vitro and in vivo antibacterial property of Ti sheet, thereby reducing bacterial-related inflammation. Quantitatively, the antibacterial rate of Ti/APS/GO/Cu against E. coli or S. aureus reached over 99%. Besides, Ti/APS/GO/Cu showed excellent biocompatibility and no toxicity to cell. Such work developed multiple sterilization avenues to design non-antibiotic, safe and efficient antibacterial implant material for the biomedical domain. [ABSTRACT FROM AUTHOR]

An injectable, highly biocompatible AgNC-reinforced hydrogel with synergistic antibacterial capability is fabricated, which can mediate the ROS balance to ameliorate oxidative stress, promote collagen deposit to facilitate re-epithelization, and significantly accelerate the infection-impaired wound healing. [Display omitted] Clinical application of antibiotic-free agents like silver nanoparticle-derived materials remains a critical challenge due to their limited long-term antibacterial activity and potential system toxicity. Herein, a highly biocompatible Ag nanocluster-reinforced hydrogel with enhanced synergistic antibacterial ability has been developed. Specifically, bioactive curcumin was incorporated into lysozyme-protected ultrasmall Ag nanoclusters (LC-AgNCs) and further integrated with sodium alginate (Sa) hydrogel (LC-AgNCs@Sa) through multiple interaction forces. Due to the synergistic antibacterial activity, LC-AgNCs could effectively kill both S. aureus and E. coli bacteria with a concentration down to 2.5 μg mL−1. In-depth mechanism investigations revealed that the bactericidal effect of LC-AgNCs lies in their bacterial membrane destruction, reactive oxygen species (ROS) production, glutathione depletion and prooxidant-antioxidant system disruption ability. Curcumin can mediate the intracellular ROS balance to protect NIH 3T3 cells from oxidative stress and improve the biocompatibility of LC-AgNCs@Sa. LC-AgNCs@Sa with long-term antibacterial ability can effectively protect the wound from bacterial invasion in vivo , and significantly accelerate the wound healing process due to their distinctive functions of inhibiting inflammatory factor (TNF-α) production, promoting collagen deposit and facilitating re-epithelization. This study provides a new, versatile strategy for the design of high-performance antibacterial dressing for broad infectious disease therapy. [ABSTRACT FROM AUTHOR]

The infection-prone wound pathology microenvironment leads to ulceration and difficult healing of diabetic wounds, which seriously affects the quality of survival of patients. In this study, natural polymer materials gelatin and polylysine were used as substrates. By introducing iron/tannic acid (FeIIITA) composite nanoparticles with excellent photothermal properties into the system, the glutamine residues of gelatin were crosslinked with the primary ammonia of polylysine by glutamine aminotransferase. A nanocomposite hydrogel with excellent antibacterial ability and NO production was constructed it was used to improve the clinical problems of diabetes wounds that were difficult to vascularize and easy to be infected. Under the premise of maintaining its structural stability, the hydrogel can be customized to meet the needs of different mechanical strengths by adjusting the ratios to match different diabetic wounds. Meanwhile, the photothermal effect of FeIIITA nanoparticles can synergize with the endogenous antibacterial ability of polylysine to improve the antibacterial efficacy of hydrogels. The potential of hydrogel to promote intracellular NO production was confirmed by fluorescent staining. Microneedle patches prepared from hydrogel can be applied to diabetic wounds, which can achieve NO deep release. Its anti-inflammatory and angiogenic abilities are also useful in achieving effective healing of diabetic wounds. [Display omitted] • A hydrogel-forming microneedle was designed for diabetic wound healing. • Enzyme-regulated for programmed NO sustained release • Endogenous/photodynamic synergistic and efficient antibacterial • Hydrogel-forming microneedles for deep subcutaneous release of NO • Microneedles promoted collagen deposition, vascular renewal, and anti-inflammatory. [ABSTRACT FROM AUTHOR]

Postharvest fruits, especially climacteric fruits, are prone to ethylene ripening, browning and aging, microbial growth accelerated decay and other problems in natural environment. Herein, a carboxylated cellulose nanofibers/phytic acid‑titanium dioxide nanoparticles (CPT) biodegradable coating with "photocatalytic antibacterial barrier" structure，was developed by homogeneous dispersion of phytic acid(PA) complexed titanium dioxide nanoparticles (TNPs) in carboxylated cellulose nanofibers(CCNF). The CPT coating achieves effective dispersion and efficient utilization of TNPs through the complexation of PA. The coating ethylene clearance rate of CPT up to 70.89 %. Meanwhile, the coating exhibits excellent antibacterial (99.67 %), UV resistance, gas barrier. It was found that the CPT coating delays fruit ripening caused by ethylene, which effectively maintaining the quality of respiratory climacteric fruits and non- climacteric fruits, extending the shelf life of perishable fruit by up to 9 days. In particular, the coating is virtually biodegradable in soil after 21 days, which offers the possibility of replacing non-biodegradable multifunctional coatings in food packaging. [Display omitted] • CPT coatings prepared by the one-pot method have excellent UV protection. • Coating has the ability to decompose ethylene and enhance antibacterial activity. • Synergistic effect of the coating for freshness preservation of different fruits. [ABSTRACT FROM AUTHOR]

The purpose of this study was to prepare Pickering emulsion with synergistic antibacterial effect using whey protein isolated-citral (WPI-Cit) nanoparticles with eugenol for grape preservation. In this emulsion, eugenol was encapsulated in oil phase. The particle size, ζ– potential, and antibacterial mechanism of the nanoparticles were characterized. The rheological properties, antibacterial effects and preservation effects of WPI-Cit Pickering emulsion were measured. The results showed that the optimal preparation condition was performed at WPI/Cit mass ratio of 1:1, WPI-Cit nanoparticles were found to damage the cell wall and membrane of bacteria and showed more effective inhibition against S. aureus. Pickering emulsion prepared with WPI-Cit nanoparticles exhibited a better antibacterial effect after eugenol was encapsulated in it, which extended the shelf life of grapes when the Pickering emulsion was applied as a coating. It demonstrated that the Pickering emulsion prepared in this study provides a new way to extend the shelf life. [Display omitted] • Whey protein isolate and citral nanoparticles were prepared by Schiff reaction. • Whey protein isolate and citral nanoparticles damaged bacteria cell wall and DNA. • Whey protein isolate-citral Pickering emulsion had antibacterial properties. • Whey protein isolate-citral Pickering emulsion and eugenol extend grape shelf life. [ABSTRACT FROM AUTHOR]

Pathogenic microbial infections have been threatening public health all over the world, which makes it highly desirable to develop an antibiotics-free material for bacterial infection. In this paper, molybdenum disulfide (MoS2) nanosheets loaded with silver nanoparticles (Ag NPs) were constructed to inactive bacteria rapidly and efficiently in a short period under a near infrared (NIR) laser (660 nm) in the presence of H2O2. The designed material presented favorable features of peroxidase-like ability and photodynamic property, which endowed it with fascinating antimicrobial capacity. Compared with free MoS2 nanosheets, the MoS2/Ag nanosheets (denoted as MoS2/Ag NSs) exhibited better antibacterial performance against Staphylococcus aureus by the generated reactive oxygen species (ROS) from both peroxidase-like catalysis and photodynamic, and the antibacterial efficiency of MoS2/Ag NSs could be further improved by increasing the amount of Ag. Results from cell culture tests proved that MoS2/Ag3 nanosheets had a negligible impact on cell growth. This work provided new insight into a promising method for eliminating bacteria without using antibiotics, and could serve as a candidate strategy for efficient disinfection to treat other bacterial infections.

Abstract Silver nanoparticles are opted to have various applications in different fields ranging from traditional medicines to culinary items. It is toxic and most effective against bacteria, fungi viruses, parasites, parasite carrying vectors such as mosquitoes and their larvae and other eukaryotic microorganisms at low concentration without any side effects and toxicity to humans. In view of these data, the present research has been investigated by synthesizing silver nanoparticles using 1mM silver nitrate and aqueous extract of Passiflora foetida. The variation of nanoparticles in size and shape concerning the concentration of extract prepared were analysed. The formation of silver nanoparticles was confirmed by colour changing from yellowish green to reddish-brown implicating the surface plasmon resonance. Further, it was concluded by obtaining an absorbance peak at 420 nm using UV-Visible spectrophotometer analysis. FTIR analysis was used to identify the capping ligands, which included alkanes, aromatic groups and nitro compounds. The average grain size of ~12 nm to 14 nm with crystalline phase was revealed by X-ray Diffraction studies. The SEM images depicted the surface morphology with agglomeration; TEM studies showed the shape of nanoparticles as spherical and hexagonal with sizes ranging from 40 nm to 100 nm and EDAX analysis confirmed the presence of elemental silver as the principal constituent. The characterized silver nanoparticles were then tested for synergistic antibacterial effects with tetracycline, and the results show that they are more active against E. coli and S. aureus, but moderately effective against B. cereus and K. pneumoniae . It also had a strong larval and pupal toxic effects on the dengue vector, Aedes aegypti with the highest mortality. As a result, silver nanoparticles could be a viable alternative for a variety of applications.

With the development of modern medicine, the use of antibiotics is more and more extensive, drug‐resistant bacteria appear, the antibacterial effect of traditional antibiotics becomes weak, and new drugs are urgently needed to solve the problem of bacterial resistance. In this paper, carbon quantum dots (CQDs) were synthesized by hydrothermal method, polypyrrole (PPy) was synthesized by chemical polymerization, and PPy/CuO/CQD ternary composite was formed by composite with copper oxide. FT‐IR and XPS were used to characterize and analyze the chemical composition of PPy/CuO/CQDs. XRD results confirmed the purity of CuO, and SEM and TEM images showed that the addition of CQDs made CuO nanorods distributed evenly on PPy nanosheets. In vitro antibacterial experiments showed that PPy/CuO/CQDs nanocomposites had high antibacterial performance against Escherichia coli, Staphylococcus aureus, and methicillin‐resistant Staphylococcus aureus. When the concentration of PPy/CuO/CQDs nanocomposites was 0.5 mg/mL, the growth inhibition of the three kinds of bacteria could reach 99.99 %, and the antibacterial effect was realized by the synergistic effect of the three components. It provides a good idea for the development of antibacterial drugs in medicine. In addition, in vitro cell proliferation experiments showed that PPy/CuO/CQDs complex had an anti‐tumor effect on HepG2 cells. [ABSTRACT FROM AUTHOR]

Excessive use of antibiotics and the formation of bacterial biofilms can lead to persistent infections caused by drug-resistant bacteria, rendering ineffective immune responses and even life-threatening. There is an urgent need to explore synergistic antibacterial therapies across all stages of infection. Drawing inspiration from the antibacterial properties of neutrophil extracellular traps (NETs) and integrating the bacterial biofilm dispersal mechanism involving boronic acid-catechol interaction, the multifunctional bismuth-based polypeptide nanonets (PLBA-Bi-Fe-TA) are developed. These nanonets are designed to capture bacteria through a coordination complex involving cationic polypeptides (PLBA) with boronic acid-functionalized side chains, alongside metal ions (bismuth (Bi) and iron (Fe)), and tannic acid (TA). Leveraging the nanoconfinement-enhanced high-contact network-driven multiple efficiency, PLBA-Bi-Fe-TA demonstrates the excellent ability to swiftly capture bacteria and their extracellular polysaccharides. This interaction culminates in the formation of a highly hydrophilic complex, effectively enabling the rapid inhibition and dispersion of antibiotic-resistant bacterial biofilms, while Fe-TA shows mild photothermal ability to further assist fluffy mature biofilm. In addition, Bi is beneficial to regulate the polarization of macrophages to pro-inflammatory phenotype to further kill escaping biofilm bacteria. In summary, this novel approach offers a promising bionic optimization strategy for treating bacterial-associated infections at all stages through synergetic treatment., (© 2024 Wiley‐VCH GmbH.)

Bacterial resistance to antibiotics can negatively affect the treatment of infected skin wounds. The combination of synergistic antibacterial therapies with photodynamic, photothermal, and chemodynamic therapies has been recognized as one of the most promising approaches. In this study, we have developed MSN@Ce6@MnO 2 -CS/Ag (MCMA) nanoparticles to serve as powerful antibacterial agents when exposed to both 660 nm visible light and 808 nm near-infrared (NIR) light. Through dual-light irradiation, MCMA can induce hyperthermia and generate reactive oxygen species (ROS), leading to a remarkable enhancement in photothermal antibacterial effects and accelerating wound healing. It has a peroxidase-like catalytic activity and promotes the generation of hydroxyl radicals (·OH) by catalyzing the decomposition of H 2 O 2 . In vitro antibacterial experiments demonstrated the excellent antibacterial activity of MCMA. The antibacterial efficacy of MCMA at a concentration of 250 μg ml -1 was found to be 99.6 and 100% toward Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli , respectively, under irradiation with an 808 and 660 nm laser. The results of the animal experiments demonstrated that MCMA can effectively accelerate wound healing through wound ulceration inhabitation. These findings substantiate the assertion that synthetic MCMA represents an efficacious strategy for bacterial inhibition and wound healing.

Drug-resistant bacteria and infectious diseases associated with biofilms pose a significant global health threat. The integration and advancement of nanotechnology in antibacterial research offer a promising avenue to combat bacterial resistance. Nanomaterials possess numerous advantages, such as customizable designs, adjustable shapes and sizes, and the ability to synergistically utilize multiple active components, allowing for precise targeting based on specific microenvironmental variations. They serve as a promising alternative to antibiotics with diverse medical applications. Here, we discuss the formation of bacterial resistance and antibacterial strategies, and focuses on utilizing the distinctive physicochemical properties of nanomaterials to achieve inherent antibacterial effects by investigating the mechanisms of bacterial resistance. Additionally, we discuss the advancements in developing intelligent nanoscale antibacterial agents that exhibit responsiveness to both endogenous and exogenous responsive stimuli. These nanomaterials hold potential for enhanced antibacterial efficacy by utilizing stimuli such as pH, temperature, light, or ultrasound. Finally, we provide a comprehensive outlook on the existing challenges and future clinical prospects, offering valuable insights for the development of safer and more effective antibacterial nanomaterials.

[Display omitted] • A synergistic anti-biofouling system was formulated and sprayed onto the AEM surface. • Exceptional static and dynamic anti-biofouling activities of as-sprayed AEMs. • Enhancement of anti-biofouling activity without sacrificing separation efficiency. • The sprayed coating overcome the "trade-off" between performance and stability. To mitigate biofouling and maintain the properties of the anion exchange membranes (AEMs) in electrodialysis (ED) processes, conferring specialized functional coatings onto surfaces has proven effective in reducing susceptibility to biofouling. In this research, AEM substrates were synthesized using the conventional chemical assembly method, involving the reaction of 1-butylimidazole (BIm) with commercially available bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO). Subsequently, a synergistic anti-biofouling system comprising graphene oxide (GO) and Ag nanoparticles (NPs) co-mingled casting-solution was formulated into a 2-μm coating through spraying onto the AEM surface. Exceptional static antibacterial activity of this system towards prevalent Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria due to contact killing mechanisms. The dynamic anti-biofilm capability of post-electrodialysis AEM was evaluated using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), revealing consistent efficacy. Notably, the enhancement of anti-biofouling properties was achieved without compromising separation efficiency, as the coating solution shares the same composition as the substrate membrane. Crucially, the co-sprayed coating technique on the AEM surface overcomes the conventional "trade-off phenomenon" between performance and stability. This approach to fabricating anti-biofouling AEMs is believed to provide valuable insights for further optimization and application, thereby facilitating their deployment in water treatment and related fields. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel MoS 2 /Cu 3 Mo 2 O 9 intelligent antibacterial nano-platform has been designed and synthesized based on DFT simulations. • The structure can effectively absorb near-infrared light, accelerate electron transfer, reduce migration resistance, and possess enhanced photothermal and photocatalytic antibacterial activity. • The structure features a unique 'activation' mechanism that can freely select and switch between 'passive defense,' 'secondary sterilization,' and 'active attack' antibacterial functions as needed. • The synergistic effect of multi-modal antibacterial capabilities was achieved, and the synergistic mechanism was investigated in detail. In this era of high drug resistance, there is an urgent need for novel antimicrobial agents and strategies to achieve smarter sterilization effects. However, developing an environmentally friendly, controllable, and self-cleaning smart antimicrobial material remains a formidable challenge. In this work, a smart antimicrobial nanoplatform composed of Cu 3 Mo 2 O 9 and MoS 2 has been successfully designed and synthesized. The computational findings reveal that, owing to the interfacial coupling between the two substances at the solid junction, this architecture can effectively absorb near-infrared light, significantly reduce migration resistance, and improve carrier separation efficiency. Empirical observations demonstrate that with a sample concentration of 100 μg/mL, under near-infrared (NIR) laser irradiation, the microenvironmental temperature proximal to the bacteria can be swiftly elevated from 28.6 °C to in excess of 50 °C within a mere 6 min. The overall photothermal conversion efficiency is 32.6 %, and it exhibits an active oxygen level nearly 5 times higher than that of Cu 3 Mo 2 O 9. Furthermore, the permeability of the cell membrane was greatly improved with the increased temperature, which is beneficial for the generated reactive oxygen species (ROS) entering the bacterial cells. After synergistic antimicrobial treatment, the antibacterial rate against Escherichia coli can reach over 99 %. More importantly, this nano-platform features a unique 'activation' mechanism that uses NIR as an 'activation switch' to selectively toggle between 'passive defense,' 'secondary sterilization,' and 'active attack' antibacterial modes as needed. Upon interaction with aqueous environments, its reusability and favorable biocompatibility with terrestrial and aquatic life promise to facilitate the intelligent eradication of deleterious microorganisms in aquatic systems via the diurnal cycle of sunrise and sunset. This is highly significant for the ongoing management and maintenance of public resources such as amusement parks, artificial fish ponds, and urban water features. [ABSTRACT FROM AUTHOR]

Nanomaterials with oxidase‐ and peroxidase‐like activities have potential in antibacterial therapy. The optimal activity of most nanozymes occurred in acidic pH (3.0–5.0), while the pH in biological systems is mostly near neutral. Herein, a general system using 9‐fluorenylmethoxycarbonyl‐modified diphenylalanine (Fmoc‐FF) hydrogel for enhancing oxidase‐ and peroxidase‐like activities of Pt NPs and other typical enzyme‐like nanomaterials at neutral or even alkaline pH is proposed. In this system, Fmoc‐FF hydrogel provides an acidic microenvironment for Pt NPs due to hydrogen protons (H+) produced by the dissociation of F at neutral pH. As a result, Pt NPs exhibits 6‐fold enhanced oxidase‐like and 26‐fold peroxidase‐like activity after being encapsulated into Fmoc‐FF hydrogel at pH 7.0. Based on outstanding enzymatic activities and the antibacterial activity of Fmoc‐FF hydrogel itself, Pt‐Fmoc‐FF hydrogel realizes excellent antibacterial effect. This design provides a universal strategy to break pH limitation of nanozymes and promotes the biological applications of nanozymes. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate framework-8 (ZIF-8) is a type of Metal-organic frameworks (MOFs), which shows promising application in the field of bacterial infection, owing to its excellent biocompatibility. Here, we report the encapsulation of silver nanoparticles (Ag NPs) in ZIF-8, accompanied with embedding of physcion (Phy) to obtain Ag-Phy@ZIF-8 with efficient and intelligent synergistic antimicrobial capabilities. Due to the micro-acidic environment around the bacteria, the release of silver and Phy shows a controlled released. Further, the Ag-Phy@ZIF-8 is modified by hyaluronate (HA), denoted as Ag-Phy@ZIF-8@HA, which has a strong inhibitory effect on the growth of both E. coli (99.1%) and S. aureus (99.5%), with no impacting on cell growth, showing good biocompatibility. Thus, these pH-responsive biocomposites have the potential application on smart wound excipients for bacterial infections. [Display omitted] • Hyaluronate (HA) was successfully modified onto Ag-Phy@ZIF-8 nanoparticles. • Ag-Phy@ZIF-8@HA nanomaterials showed efficient synergistic antibacterial activity for E. coli (99.1%) and S. aureus (99.5%). • Ag-Phy@ZIF-8@HA nanomaterials exhibited good stability and biocompatibility. [ABSTRACT FROM AUTHOR]

Although many advances have been made in medicine, traumatic bleeding and wound infection are two of the most serious threats to human health. To achieve rapid hemostasis and prevent infection by pathogenic microbes, the development of new hemostatic and antibacterial materials has recently gained significant attention. In this paper, safe, non-toxic, and biocompatible polyvinyl alcohol (PVA); carboxymethyl cellulose (CMC), which contains several carboxyl and hydroxyl groups; and polyethylene glycol (PEG), which functions as a pore-forming agent, were used to prepare a novel PVA/CMC/PEG-based composite hydrogel with a macroporous structure by the freeze-thaw method and the phase separation technique. In addition, a PVA/CMC/PEG@ZIF-L composite hydrogel was prepared by the in situ growth of zeolitic imidazolate framework-L (ZIF-L). ZIF-L grown in situ on hydrogels released Zn2+ and imidazolyl groups. They elicited a synergistic antibacterial effect in hemostasis with PVA and CMC, rendering the PVA/CMC/PEG@ZIF-L hydrogel with a good antibacterial effect against Staphylococcus aureus. At the same time, the macroporous structure enabled the rapid release of Zn2+ and imidazolyl groups in ZIF-L and promoted cell proliferation at an early stage, enhancing the coagulation efficiency. A rat liver injury model was used to confirm its rapid hemostasis capacity. [ABSTRACT FROM AUTHOR]

Rare earth elements have special electron layer structure, so they show excellent optical, magnetic, electrical, and catalytic properties, and have been widely used in the antibacterial field. This paper introduces the antibacterial properties of rare earth ions and rare earth oxides and its antibacterial mechanism, explores the synergistic antibacterial effect of compound antibacterial agent of the rare earth organic compound and inorganic antibacterial agent and rare earth elements, enumerates the rare earth inorganic composite antimicrobial agent in coatings, plastics, ceramics, and fabrics in the areas of application. Finally, the application prospect of rare earth in antibacterial materials is prospected and some problems to be solved are put forward. [ABSTRACT FROM AUTHOR]

[Display omitted] Enhancing long-term antibacterial activity of membrane materials is an effective strategy to reduce biological contamination. Herein, we developed a long-term, synergistic antibacterial polyacrylonitrile (PAN) nanofiber membrane by a "one-pot" electrospinning process. In the reaction solution of PAN and N, N -dimethylformamide (DMF), silver-silicon dioxide nanoparticles (Ag@SiO 2 NPs) are in-situ synthesized and stabilized using silane coupling agent; and [2-(methacryloyloxy)-ethyl] trimethylammonium chloride (MT) monomers are then in-situ cross-linked to obtain a polyquaternary ammonium salt (PMT). Subsequently, the casting solution is directly used to fabricate Ag@SiO 2 /PMT-PAN nanofibrous membrane (NFM) via electrospinning. The antibacterial activity, reusability, synergy effect and biological safety of the Ag@SiO 2 /PMT-PAN NFM are systematically investigated, and the synergistic antibacterial mechanism is also explored. Even at very low (0.3 wt%) content of silver, the Ag@SiO 2 /PMT-PAN NFM exhibits excellent antibacterial activity against E. coli (99%) and S. aureus (99%). Also, the antibacterial ability of the NFM remains the same level after three cycles of antibacterial processes with the efficient synergy effects of Ag@SiO 2 and PMT components. When the Ag@SiO 2 /PMT-PAN contacts with bacteria, the PMT attracts and kills the bacteria through electrostatic action. The bacteria with damaged cell membranes are deposited on the nanofibrous membrane, which could greatly promote the release of Ag+ and further enhance the antibacterial activity. Moreover, L929 fibroblasts are co-cultured with the extract of 4 mg/mL Ag@SiO 2 /PMT-PAN for 5 days, which exhibits a low cytotoxicity with a cell proliferation ratio of 95%. This work opens new pathways for developing long-term effective and synergistic antibacterial nanofibrous membrane materials to prevent infections associated with biomedical equipment. [ABSTRACT FROM AUTHOR]

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology 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.)

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office 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.)

[Display omitted] • Multifunctional nanozymes with space-confinement effect were synthesized. • Space-confined nanozymes significantly improve catalytic effects. • Cascade nanozymes have synergistic antibacterial effects. • Nanozymes with nanoconfinement can be used for synergistic antibacterial treatment and fluorescence imaging of bacterial infections. The rapid development of bacterial infections has become a significant global health challenge. The overuse or prolonged use of antibiotics is considered a major contributor to the development of bacterial resistance. Therefore, there is an urgent need to develop a new therapeutic approach to combat infectious diseases caused by bacteria. In this study, we demonstrate the effectiveness of a novel strategy for synergistic antibacterial therapy and fluorescence imaging of wound bacterial infections through the nano-confined construction of LL-37-HA-Au-Pt@PCN-224 nanozymes. The nanozyme is composed of Au NPs and Pt NPs confined to PCN-224 through in situ reduction, with its outer layer modified with HA and LL-37. The nanozyme catalyzes the conversion of low-concentration H 2 O 2 into O 2 and •OH, with the generated O 2 further catalyzed into 1O 2 by PCN-224. In vivo imaging experiments demonstrate that LL-37-HA-Au-Pt@PCN-224 labeled with near-infrared fluorescent dye MPA can effectively realize fluorescence imaging of wound bacterial infections and real-time monitoring of the wound healing process. In vitro and in vivo antibacterial experiments reveal that LL-37-HA-Au-Pt@PCN-224 enhances the healing efficiency of bacteria-infected wounds due to its synergistic antibacterial effect. The multifunctional nanozyme offers various synergistic antibacterial therapies, including antimicrobial peptides, peroxide nanozymes, hydrogen peroxide nanozymes, and photodynamic therapy. Moreover, it provides real-time wound imaging and monitoring of the wound healing process, while maintaining high biocompatibility. Overall, this study presents a promising perspective on the potential use of nanozymes as antibacterial agents against wound bacterial infections in the future. [ABSTRACT FROM AUTHOR]

• Supramolecular binding strategy was developed to prepare novel COFs. • β-CD inclusion was used as building block for the preparation of COFs. • Por-CD-COF could greatly reduce the use of photoactive ingredients. • The threading of CD could significantly enhance the photoactivity of COFs. • Por-CD-COF exerted cyclodextrin enhanced PTT and PDT. As an emerging artificial porous material, covalent organic frameworks (COFs) with customizable structure and function, have always been the focus of polymer science. Controllable fabrication of COFs with brand-new structure is the top priority for its development. Here, the 'supramolecular binding' strategy is developed as a simple but efficient method to prepare COFs with novel structures and functions. By this means, polymeric rotaxanes threaded COFs, denoted as Por-CD-COF, was facilely prepared via the combination of dynamic covalent imine-bond formation with supramolecular self-assembly, in which the polyrotaxane formed via inclusion of aromatic linker with bactericidal active β-cyclodextrin macrocycle (CD) was condensed with the photosensitive porphyrin via the combination of mechanical grinding and solvothermal synthesis. The formation of polyrotaxane could change the distance between layers, avoiding the quench of photoactivity caused by the severe aggregation of layered structure. Under the same molar amount of reaction monomers, the weight of the Por-CD-COF is approaching five times of the CD-free COF, which could greatly reduce the use of photoactive ingredients. Further experiments demonstrated the introduction of CDs could also significantly improve the biocompatibility. Impressively, this special porphyrin-involved CD-COF, displays excellent photo activity, which could act as an efficient broad spectrum antibacterial agents realizing the combinational action of cyclodextrin enhanced photothermal and photodynamic antimicrobial at an extremely low quality of the effective photosensitizer (Porphyrin). Meanwhile, even at the same dose of fungicide, the bactericidal effect of Por-CD-COF is far exceeding the CD-free therapeutic agent. This novel synthetic strategy allows the incorporation of mechanically interlocked CDs (MIMs) into the porous polymeric materials, providing an easy access to low-cost preparation of COFs for the specific applications. [ABSTRACT FROM AUTHOR]

Although many advances have been made in medicine, traumatic bleeding and wound infection are two of the most serious threats to human health. To achieve rapid hemostasis and prevent infection by pathogenic microbes, the development of new hemostatic and antibacterial materials has recently gained significant attention. In this paper, safe, non-toxic, and biocompatible polyvinyl alcohol (PVA); carboxymethyl cellulose (CMC), which contains several carboxyl and hydroxyl groups; and polyethylene glycol (PEG), which functions as a pore-forming agent, were used to prepare a novel PVA/CMC/PEG-based composite hydrogel with a macroporous structure by the freeze-thaw method and the phase separation technique. In addition, a PVA/CMC/PEG@ZIF-L composite hydrogel was prepared by the in situ growth of zeolitic imidazolate framework-L (ZIF-L). ZIF-L grown in situ on hydrogels released Zn2+ and imidazolyl groups. They elicited a synergistic antibacterial effect in hemostasis with PVA and CMC, rendering the PVA/CMC/PEG@ZIF-L hydrogel with a good antibacterial effect against Staphylococcus aureus. At the same time, the macroporous structure enabled the rapid release of Zn2+ and imidazolyl groups in ZIF-L and promoted cell proliferation at an early stage, enhancing the coagulation efficiency. A rat liver injury model was used to confirm its rapid hemostasis capacity.

Bacterial biofilm formation is associated with the pathogenicity of pathogens and poses a serious threat to human health and clinical therapy. Complex biofilm structures provide physical barriers that inhibit antibiotic penetration and inactivate antibiotics via enzymatic breakdown. The development of biofilm-disrupting nanoparticles offers a promising strategy for combating biofilm infections. Hence, polyethyleneimine surface-modified silver-selenium nanocomposites, Ag@Se@PEI (ASP NCs), were designed for synergistic antibacterial effects by destroying bacterial biofilms to promote wound healing. The results of in vitro antimicrobial experiments showed that, ASP NCs achieved efficient antibacterial effects against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by disrupting the formation of the bacterial biofilm, stimulating the outbreak of reactive oxygen species and destroying the integrity of bacterial cell membranes. The in-vivo bacterial infection in mice model showed that, ASP NCs further promoted wound healing and new tissue formation by reducing inflammatory factors and promoting collagen fiber formation which efficiently enhanced the antibacterial effect. Overall, ASP NCs possess low toxicity and minimal side effects, coupled with biocompatibility and efficient antibacterial properties. By disrupting biofilms and bacterial cell membranes, ASP NCs reduced inflammatory responses and accelerated the healing of infected wounds. This nanocomposite-based study offers new insights into antibacterial therapeutic strategies as potential alternatives to antibiotics for wound healing., (© 2024 IOP Publishing Ltd.)

Bacterial invasion hinders the healing process of wound, leading to the formation of chronic infected wound; meanwhile, the misuse of antibiotics has resulted in the emergence of numerous drug-resistant bacteria. The application of conventional antimicrobial methods and wound treatment techniques is not appropriate for wound dressings. In this paper, quaternized poly(vinyl alcohol) (QPVA) and pomegranate-like copper uniformly doped polydopamine nanoparticles (PDA@Cu) were introduced into a gelatin-oxidized carboxymethyl cellulose system to form a multicomponent synergistic antibacterial hydrogel (GOQ 3 P 3 ). Polydopamine improves the biocompatibility and prevents the detachment of Cu nanoparticles. It can achieve synergistic antibacterial effects through quaternary ammonium salt-inorganic nanoparticle photothermal treatment under 808 nm near-infrared (NIR) irradiation. It exhibits highly efficient and rapid bactericidal properties against Escherichia coli , Staphylococcus aureus , and MRSA (methicillin-resistant Staphylococcus aureus ) with an antibacterial rate close to 100%. The gel scaffold composed of macromolecules gives the hydrogel excellent mechanical properties, adhesive capabilities, self-healing characteristics, biocompatibility, and pH degradation and promotes cell adhesion and migration. In a full-thickness wound healing model infected with MRSA , GOQ 3 P 3 controls inflammatory responses, accelerates collagen deposition, promotes angiogenesis, and enhances wound closure in the wound healing cascade reaction. This study provides a feasible strategy for constructing dressings targeting chronic infection wounds caused by drug-resistant bacteria.

Copyright of Journal of East China University of Science & Technology is the property of Journal of East China University of Science & Technology Editorial Office 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.)

[Display omitted] • The NIR-responsive of Mo/Fe@CuO 2 nanozyme was synthesized successfully. • Mo/Fe@CuO 2 nanozyme could achieve H 2 O 2 self-supply and highly efficient peroxidase-like activity by CuO 2 NPs and Mo/Fe CDs. • Mo/Fe@CuO 2 nanozyme possessed strong antibacterial activities under NIR irradiation. • Mo/Fe@CuO 2 nanozyme exhibited excellent photodynamic performance, and photostability during NIR irradiation. Nanozymes have drawn increasing attention due to unique enzyme-mimic catalytic activities for the treatment of bacterial infections. Herein, a novel tri-metal nanozyme for synergistic eradication of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was generated by Mo/Fe doped carbon dots (Mo/Fe-CDs) wrapping copper peroxide (CuO 2) nanozyme (Mo/Fe@CuO 2). Mo/Fe@CuO 2 showed near-infrared (NIR) light-enhanced peroxidase-like catalytic activity, and H 2 O 2 self-supply to promote the generation of reactive oxygen species (ROS) for highly efficient antibacterial photothermal therapy. The CuO 2 could generate H 2 O 2 in the acidic microenvironment, and Mo/Fe-CDs consequently could convert H 2 O 2 to hydroxyl radicals (·OH), resulting in the improvement of sterilization efficiency. Interestingly, Mo/Fe-CDs could activate the transformation of Cu2+ to Cu+ through the co-catalytic reaction based on the Mo4+/Mo6+ and Fe3+/Fe2+ redox couples, and provided photonic hyperthermia (PTT) to enhance the peroxidase-like activity. Meanwhile, Mo/Fe@CuO 2 showed glutathione (GSH) oxidase-like activity, which can achieve the depletion of glutathione (GSH) in bacteria, thus significantly improving the bactericidal effect. The collaborative eradication of bacteria, through innovative metal carbon-based nanozyme technology, provides a powerful and feasible approach to treating bacterial infections that threaten human health. [ABSTRACT FROM AUTHOR]

Antimicrobial packing showed great potential in extending the shelf life of food. However, developing a new biocomposite film with an intelligent and efficient antimicrobial performance is still desirable. Herein, a Fe-MoO x encapsulated with curcumin (Cur) filled chitosan-based composite film (CCF films) was prepared by solvent casting method. The total color differences of the CCF films were less than 30%, and satisfactory surface color, transparency, hydrophobicity, and thermal stability were also obtained. Besides, the UV-light/water/oxygen barrier capability and mechanical properties were enhanced with the incorporation of Cur@Fe-MoO x . Moreover, CCF films showed photothermal performance and thermal-controlled curcumin release ability, which endowed the CCF 0.15 film with excellent antibacterial capability toward E. coli (≥99.95%) and S. aureus (≥99.96%) due to the synergistic antibacterial effect. Fe-MoO x exhibited high cell viability and less than 5% hemolysis even under the concentration of 500 μg mL -1 . Based on those unique characteristics, the CCF 0.15 film was chosen for tangerine preservation. The CCF 0.15 film could prolong the shelf life of tangerine by at least 9 days compared with the unpacking group, and the tangerines could maintain the freshness characteristics over a 24 day storage period. Such thermal-mediated antibacterial film proposed by our work showed promising potential in food packaging.

Abstract Due to their remarkable antibacterial properties, silver nanoparticles (Ag NPs) and curcumin (CCM) have been widely used in the antimicrobial field. In our study, we have fabricated the uniform and stable silver/curcumin composite nanoparticles by a facile ultrasound treatment process and the synergistic antibacterial activity were evaluated. The curcumin not only played a role of reducing agent but also acted as a capping agent. The antibacterial effects of silver/curcumin (cAgNPs) were studied by measuring the growth curve and surface plate assay based on the E. coli and B. subtilis , which showed concentration dependent bacteriostatic and bactericidal effects of cAgNPs. The presence of CCM enhance the binding of Ag to bacterial membrane and Ag+ release in comparison to that without CCM, so that creating a temporary and local high Ag+ concentration near the surface of the bacterium, meanwhile, generation of more reactive oxygen species, lead to membrane damage, bacterial lipases and induce leakage of intracellular contents followed by bacterial death that lead to growth inhibition of the bacteria. The antibacterial effects were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the effect which were further found to decrease by introducing antioxidant N -acetyl- l -cysteine (NAC) act as a reactive oxygen species (ROS) scavenging agent. These initial data suggest that cAgNPs have a highly antibacterial efficient and might have potential to be developed as an effective antimicrobial nanomaterial. Highlights • Curcumin not only played a role of reducing agent but also acted as a capping agent; • Curcumin enhance the binding of Ag to bacterial membrane and Ag+ release; • Creating a temporary and local high Ag+ concentration near the surface of the bacterium; • Generation of more reactive oxygen species, lead to membrane damage, bacterial lipases and intracellular contents leakage. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selective detection of PC-PFTs secreting bacteria. • Guiding and performing the effective antibacterial strategy on site. • Self-induced ROSs and NO for bacterial inactivation in the dark. Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a frequent cause of purulent skin and soft tissue infections. In this study, a test-to-treat chip was developed as an integrated platform for the highly sensitive detection and treatment of MRSA infections. By integrating arginine (Arg) ligand-doped FeMOFs onto TiO 2 nanotube arrays (TNT), the resulting Arg-FeMOF-TNT chips exhibited excellent photoelectrochemical (PEC) activity under visible-light irradiation. As phosphatidylcholine (PC) specific pore-forming toxins (PC-PFTs) secreted by MRSA can specifically generate small holes in the phospholipid membrane (PM), the PM covered Arg-FeMOF-TNT photoactive surface can be re-exposed to the electrolyte in the presence of PC-PFTs and then reacted with electron donors in the electrolyte. On the basis of switch-on PEC signals, a detection limit as low as 6 CFU mL−1 was achieved for MRSA. Furthermore, benefitting from its intrinsic photocatalytic activity, the Fenton-like catalytic activity of FeMOFs, and the loaded Arg on the chip, abundant reactive oxygen species (ROSs) and nitric oxide (NO, arginine decomposition product) were generated in the bacterial microenvironment, resulting in the effective sterilization of MRSA. Importantly, the PM modification endow the chip to process good biosafety and remarkable antibacterial specificity towards MRSA. Animal experiment results further demonstrated that the chip can rapidly kill MRSA in wounds and promote wound healing under 532-nm-laser irradiation. This all-in-one chip offers a new method for the diagnosing bacteria and also provides new insight into the design of test-to-treat platforms for PC-PFTs bacteria. [ABSTRACT FROM AUTHOR]

The combination of natural antimicrobial peptide BCp12/phenyllatic acid (BCp12/PLA) presents a more efficient antibacterial effect, but its antibacterial mechanism remains unclear. This study studied the synergistic antibacterial mechanism of BCp12 and PLA against S. aureus. The results demonstrated that the BCp12/PLA combination presented a synergistic antibacterial effect against S. aureus , with a fractional inhibitory concentration of 0.05. Furthermore, flow cytometry and scanning electron microscope analysis revealed that BCp12 and PLA synergistically promoted cell membrane disruption compared with the group treated only with one compound, inducing structural cell damage and cytoplasmic leakage. In addition, fluorescence spectroscopy analysis suggested that BCp12 and PLA synergistically influenced genomic DNA. BCp12 and PLA targeted enzymes related to peptidoglycan and DNA synthesis and interacted by hydrogen bonding and hydrophobic interactions with mur enzymes (murC, murD, murE, murF, and murG), dihydrofolate reductase, and DNA gyrase. Additionally, the combined treatment successfully inhibited microbial reproduction in the storage of pasteurized milk, indicating that the combination of BCp12 and PLA can be used as a new preservative strategy in food systems. Overall, this study could provide potential strategies for preventing and controlling foodborne pathogens. • BCp12 combined with PLA has synergistic antibacterial effect. • BCp12 combined with PLA destroyed the integrity and permeability of cell wall membrane. • BCp12 combined with PLA interfered with the synthesis of peptidoglycan. • BCp12 combined with PLA affected DNA synthesis and self-replication. • The BCp12 combined with PLA is a new and efficient food preservative. [ABSTRACT FROM AUTHOR]

Developing low-cost and easy-accessible phototherapy agents with a high sterilization efficiency is urgently needed tackling the increasingly dangerous of bacterial infections. Herein, a broad-spectrum antimicrobial agent (i.e., PP-Mo-NO) with near-infrared laser (NIR) driven nitric oxide (NO) release capacity derived from the assemble of a heat-sensitive NO donor (N, N′ -di-sec-butyl- N, N′ -dinitroso-1, 4-phenylenediamine, BNN6) with freeze-dried three-dimensional polypyrrole hydrogel crosslinked by the sulfonated dimolybdenum-salen (PP-Mo), was synthesized for the rapid and effective eradicating of Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Upon 808 nm laser irradiation, PP-Mo-NO showed not only superb photothermal efficacy (79.88 %), but also precisely controllable NO release capacity, generating oxidative/nitrosative stress. Within 10 mins of irradiation (1.0 W cm−2), PP-Mo-NO with co-amplified photothermal (PTT)/NO synergetic antibacterial activity presented sterilization rates beyond 99.1% against both the E. coli and S. aureus at a relatively low concentration (100 µg mL−1). Meanwhile, in vivo experiments demonstrated the great application potential of PP-Mo-NO which could effectively kill bacteria at the site of infection, and repair the open infectious wounds, thereby accelerating the tissue reconstruction. [Display omitted] • A polypyrrole hydrogel-based antimicrobial agent (PP-Mo-NO) was developed. • Upon laser irradiation, PP-Mo-NO showed superb photothermal efficacy (79.9 %). • PP-Mo-NO realized the precisely controllable NO release to the infection site. • PP-Mo-NO showed amplified PTT/NO synergetic antibacterial activity capacity. • PP-Mo-NO can repair infectious wounds, accelerate the tissue reconstruction. [ABSTRACT FROM AUTHOR]

The hull and subsea equipment are often plagued by widespread marine biofouling, so developing a sustainable environmental protection antifouling paint is urgent. The study designed and developed an antifouling composite coating system (E44-Ag-PGI) with a synergistic antibacterial effect based on the dual strategy of the bacteriostatic effect of stereochemical structure on polymer surface and release sterilization of metal nanoparticles. Firstly, an antifouling agent (PGI) was prepared by simple radical polymerization by combining glycidyl methacrylate with borneol, a complex bicyclic monoterpene structure extracted from plants. Then bisphenol A epoxy resin with strong adhesion to metal was selected as the base material. The synthetic antifouling agent with epoxy groups was polymerized in situ into the epoxy resin network, and compared with pure epoxy resin, the elongation at break of E44-Ag-PGI coating with 20 % PGI content increased from 40.37 % to 124.8 %, which was mainly attributed to the introduction of a soft chain of antifouling agent polymer, which improved the flexibility of the coating. Meanwhile, the antibacterial efficiency of the coating against Pseudomonas aeruginosa and Staphylococcus aureus was 97.69 % and 95.9 %, respectively. This excellent antibacterial performance was mainly attributed to the synergistic antibacterial action of natural borneol and AgNPs. In addition, the biofilm and diatom resistance experiments of the coating showed that the coating also has an excellent antifouling effect. This provided a new research idea for environmentally friendly antifouling coatings. [Display omitted] • Surface stereochemical bacteriostasis and release bactericidal dual strategies • Environmental protection antifouling agent based on natural borneol synthesi. • Antifouling agent is introduced into epoxy resin network by in-situ polymerization. [ABSTRACT FROM AUTHOR]

Abstract: To satisfy the ever‐growing demand in bacterial infection therapy and other fields of science, great effort is being devoted to the development of methods to precisely control drug release and achieve targeted use of an active substance at the right time and place. Here, a new strategy for bacterial infection combination therapy based on the light‐responsive zeolitic imidazolate framework (ZIF) is reported. A pH‐jump reagent is modified into the porous structure of ZIF nanoparticles as a gatekeeper, allowing the UV‐light (365 nm) responsive in situ production of acid, which subsequently induces pH‐dependent degradation of ZIF and promotes the release of the antibiotic loaded in the mesopores. The combination of the UV‐light, the pH‐triggered precise antibiotic release, and the zinc ions enables the light‐activated nanocomposite to significantly inhibit bacteria‐induced wound infection and accelerate wound healing, indicating a switchable and synergistic antibacterial effect. The light irradiated accumulation of acid ensures the controlled release of antibiotic and controlled degradation of ZIF, suggesting the therapeutic potential of the metal–organic frameworks‐based smart platform for controlling bacterial infection. [ABSTRACT FROM AUTHOR]

In this study, an Ag/zeolitic-imidazolate framework (ZIF-8)/Mg-Al layered double hydroxide (LDH) (Ag/ZIF-8/LDH) composite coating was prepared on the surface of a micro-arc oxidation (MAO)-pretreated magnesium alloy through a hydrothermal reaction with the addition of ZIF-8 nanoparticles in a hydrothermal solution. The influence of the ZIF-8 nanoparticles on the corrosion resistance, biocompatibility, antimicrobial properties, and osteogenicity of the composite coatings was systemically investigated. The results indicated that the formed Ag/ZIF-8/LDH composite nanosheets sealed the micropores and cracks in the MAO coating well, resulting in a more integrated and denser morphology. The ZIF-8-comprising composite coating exhibited better corrosion resistance in vitro. In addition, the Zn2+ in ZIF-8 and Ag+ release of the Ag nanoparticles in the coating, together with the good photothermal conversion performance of the Ag/ZIF-8/LDH coating, could quickly generate photothermal temperature under near-infrared light, to achieve a synergistic antibacterial effect. The effective antibacterial coefficients against Staphylococcus aureus and Escherichia coli were 99.8 % and 99.89 %, respectively. Additionally, the cells on the composite coating exhibited good osteogenic activity with higher alkaline phosphatase (ALP) activity because of the Zn2+ and Mg2+ from the LDH. This strategy may be a promising approach for post-treatment of MAO coatings to enhance protection and provide multiple functionalities for biomedical Mg alloys. [Display omitted] • Adding ZIF-8 enhanced corrosion resistant of composite coating on MAO surface. • Synergistic effect of Zn2+ and Ag improved coating antibacterial on Mg alloy. • Zn2+ and Mg2+ releasing from composite coating fulfilled better osteogenic activity. [ABSTRACT FROM AUTHOR]

Biofouling is one of significant obstacles decaying the high separation performance and long-term stability of polymer membranes during the application. To explore the desirable anti-biofouling anion exchange membrane (AEM), in this work, a series of modified AEMs having surface antibacterial functional layers on surface has been prepared by using gentamicin and N-chloramine for electrodialysis (ED). The antibacterial functional layer on surface was constructed via chemical assembly. By using CuSO 4 and H 2 O 2 as the trigger, l -dopa was oxidized on surface of commercial AEM (Fuji type II) to form a carboxyl layer. Thereafter, gentamicin was chemically assembled via the amide condensation reaction. It was chlorinated with diluted NaClO solution to endow it with synergistic antibacterial activity by using gentamicin. Investigation demonstrates that the optimized membrane of P(l -Dopa)@GM-Cl has high antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Among them, flow cytometry shows that the antibacterial rate of P(l -Dopa)@GM-Cl against E. coli is more than 99%, which is much higher than original membrane (28.4%). P(l -Dopa)@GM-Cl exhibits the enhanced performance in inhibiting biofilm observed by scanning electron microscopy analysis. This work may provide a reference for the construction of anti-biofouling ion exchange membrane. [Display omitted] • An AEM with synergistic antibacterial performance was prepared via chemical assembly. • The optimized AEM shows a good resistance to chemical contamination. • The as-prepared AEM has high antibacterial rate of 99% against both E. coli and S. aureus. • Chemically assembled AEM has inhibition effect of biofilm formation. [ABSTRACT FROM AUTHOR]

Antibiotics overuse and misuse increase the emergence of multidrug-resistant bacterial strains, which often leads to the failure of conventional antibiotic therapies. Even worse, the tendency of bacteria to form biofilms further increases the therapeutic difficulty, because the extracellular matrix prevents the penetration of antibiotics and triggers bacterial tolerance. Therefore, developing novel antibacterial agents or therapeutic strategies with diverse antibacterial mechanisms and destruction of bacteria biofilm is a promising way to combat bacterial infections. In the present study, the combination of quaternary ammonium compound poly(diallyl dimethyl ammonium chloride) (PDDA) with Cu2+ was screened out to fight common pathogenic Staphylococcus aureus (S. aureus) through multi-mechanisms. This combination appeared strong synergistic antibacterial activity, and the fractional inhibitory concentration index was as low as 0.032. The synergistic antibacterial mechanism involved the destruction of the membrane function, generation of intracellular reactive oxygen, and promotion more Cu2+ into the cytoplasm. Further, the combination of PDDA and Cu2+ reduced the extracellular polysaccharide matrix, meanwhile killing the bacteria embedded in the biofilm. The biocompatibility study in vitro revealed this combination exhibited low cytotoxicity and hemolysis ratio even at 8 times of minimum bactericidal concentration. This work provides a novel antibacterial agents combination with higher efficiency to fight planktonic and biofilm conditions of S. aureus. Quaternary ammonium compound poly(diallyl dimethyl ammonium chloride) and Cu2+ presented significantly synergistic antibacterial activity against planktonic and biofilm conditions of S. aureus. This combination had diverse antibacterial mechanisms, including destruction of membrane function, promotion Cu2+ into cytoplasm, generation of intracellular reactive oxygen and destroy extracellular polysaccharide. [Display omitted] • Poly(diallyl dimethyl ammonium chloride) and Cu2+ had strong synergistic effect. • The combination damaged mature biofilm. • This combination exerted antibacterial effects through multiple mechanisms. • This combination exhibited high biocompatibility in vitro. [ABSTRACT FROM AUTHOR]

The gas therapy of some endogenous signaling molecules to treat diseases has caused extensive research, among which NO gas has shown great potential in fighting infection with various pathogens, promoting wound healing, etc. Here, we propose a photothermal/photodynamic/NO synergistic antibacterial nanoplatform by loading L -arginine (LA) on mesoporous TiO 2 and then encapsulating it with polydopamine. The obtained TiO 2−x -LA@PDA nanocomposite possesses both the excellent photothermal effect and ROS generation ability of mesoporous TiO 2 , and the release of nitric oxide (NO) from L -arginine under near-infrared (NIR) light irradiation, while the sealing layer of PDA could induce NIR-triggered NO controlled release. In vitro antibacterial experiments confirmed that the synergistic effect of TiO 2−x -LA@PDA nanocomposites has excellent antibacterial effects against Gram-negative and Gram-positive bacteria, while in vivo experiments showed that it has lower toxicity. It is worth noting that compared with the pure photothermal effect and ROS, the generated NO showed a better bactericidal effect, and NO had a better ability to promote wound healing. In conclusion, the developed TiO 2−x -LA@PDA nanoplatform can be used as a nanoantibacterial agent, which can be further explored in the related biomedical field of photothermal activation of multimodal combined antibacterial therapy. [Display omitted] • TiO2-x-LA@PDA nanoplatform were constructed by electrostatic adsorption and polymerization. • The nanoplatform has a synergistic nitric oxide, photothermal, and photodynamic antibacterial effect. • It has more than 99% killing effect on Granz positive and negative bacteria. • The nanoplatform can promote bacterial infectious wound healing. [ABSTRACT FROM AUTHOR]

Multidrug-resistant Staphylococcus aureus , a Gram-positive bacterium that causes several difficult-to-treat human infections, is a considerable threat to global healthcare. We hypothesize that there exist inner responsive molecules (IRMs) which can function synergistically with antibiotics to restore the sensitivity of resistant bacteria to existing antibiotics without inducing new antibiotic resistance. An investigation of the extracts of the Chinese medicinal herb Piper betle L. led to the isolation of six benzoate esters, BO-1 - BO-6 . Among these, BO-1 as a distinct IRM displayed considerable synergism by potentiating antibacterial activity against five antibiotic-resistant S. aureus strains. Mechanistic studies demonstrated that BO-1 acted as a suppressing drug resistance IRM via inhibiting efflux activity. A combination of BO-1 with ciprofloxacin significantly inhibited resistance to this antibiotic and reversed its resistance in the S. aureus strain. Furthermore, BO-1 effectively enhanced the activity of ciprofloxacin against the efflux fluoroquinolone-resistant S. aureus strain SA1199B that caused infection in two animal models and significantly decreased the inflammatory factors IL-6 and C-reactive protein of the infected mice, thereby showing the practice utility of this approach.

Pathogens transmitted through the water environment pose a great threat to human health. Hence developing more reliable and efficient antibacterial materials to eliminate bacterium in water environments is urgent. Herein, we posed a novel strategy of interweaving carboxymethyl chitosan (CMCS) and Ag/Cu-MOFs to construct renewable Ag/Cu-BTC@CMCS composite beads with rapid sterilization, long-term antibacterial effects and high biosafety. Characterizations revealed that CMCS and bimetallic MOFs act as the "warehouses" of metal ions and played key roles in anchoring, storage, delivery, and controlled release of metal ions. The synergistic antibacterial effect achieved by the combination of Ag+ and Cu2+ provides the composite beads with high antibacterial efficiency, resulting in low minimum inhibitory concentrations (0.32 mg/mL against E. coli and 0.16 mg/mL against S. aureus) and over 99.9 % bacteria killing rate. Benefiting from the rapid release of metal ions from polymer chains and the long-term release from MOFs, the composite beads can effectively sterilize the simulated swimming pool water in 2 h and persistently inhibit bacterial reproduction over 48 h, and show a safe level of residual heavy metals because of the chelation of CMCS. This work provides new insights and promises a strategy for the design and commercial application of novel water fungicides. [Display omitted] [ABSTRACT FROM AUTHOR]