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Gold nanoclusters (Au NCs) capped with a small biomolecule, namely (+)‐norephedrine, (Au@Nore) display exceptional performance as fluorescent pH sensors. They display high emission quantum yield (ΦPL of ≈33% in strongly basic media); absence of nanocluster (NC) aggregation and/or induced rigidification of the organic shell; a linear dependency of their emission on the pH in the 8.2–9.5 range; and reversible pH sensing. In addition, excitation at 310 nm, where both the NC and the ligand absorb, enables ratiometric sensing. Studies on the fungus Candida albicans and bacterium Bacillus subtilis demonstrate that while Au@Nore do not cause any impact on the growth of the fungus, it inhibited the growth of the Bacillus, showing the lowest cell viability of 18% at the highest pH values via a mechanism of action involving the disruption of the bacterial wall. [ABSTRACT FROM AUTHOR]

Wound healing represents a complex biological process often hampered by bacterial infections, in particular those caused by Staphylococcus aureus, which is already multiresistant to many antibiotics. In this sense, enzybiotics have additional advantages over conventional antibiotics, since they provide pathogen specificity and do not contribute to antibiotic resistance. However, their soluble administration at the wound site would result in enzyme leakage. On the other hand, bacterial cellulose (BC) pellicles present a very promising dressing and scaffold, given its high purity, water retention capacity, and barrier effect in the wound against possible contaminants. In this study, we present a novel approach that incorporates the enzybiotic CHAPK into BC to develop functionalized membranes that exhibit targeted and controlled antimicrobial activity against S. aureus. The kinetic tests revealed a continuous loading of the enzybiotic into BC until it reaches a maximum and a two-stage release process, characterized by an initial fast release followed by a sustained release. Attenuated total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM) confirmed the incorporation and the preferential surface localization of CHAPK within the BC membranes. Finally, the BC/CHAPK materials demonstrated the sustained reduction of up to 4 logarithmic units in the viability of S. aureus. Overall, the biomaterials developed here exhibit promising antimicrobial efficacy against S. aureus, offering a potential strategy for wound management and skin infection control while maintaining unharmed the commensal skin microbiota, which impairment could compromise the integrity of the skin barrier function. [ABSTRACT FROM AUTHOR]

Modern consumption patterns have led to a surge in waste glass accumulating in municipal landfills, contributing to environmental pollution, especially in countries that do not have well-established recycling standards. While glass itself is 100% recyclable, the logistics and handling involved present significant challenges. Flint and amber-colored glass, often found in high quantities in municipal waste, can serve as valuable sources of raw materials. We propose an affordable route that requires just a thermal treatment of glass waste to obtain glass-based antimicrobial materials. The thermal treatment induces crystallized nanoregions, which are the primary factor responsible for the bactericidal effect of waste glass. As a result, coarse particles of flint waste glass that undergo thermal treatment at 720 °C show superior antimicrobial activity than amber waste glass. Glass-ceramic materials from flint waste glass, obtained by thermal treatment at 720 °C during 2 h, show antimicrobial activity against Escherichia coli after just 30 min of contact time. Laser-induced breakdown spectroscopy (LIBS) was employed to monitor the elemental composition of the glass waste. The obtained glass-ceramic material was structurally characterized by transmission electron microscopy, enabling the confirmation of the presence of nanocrystals embedded within the glass matrix. [ABSTRACT FROM AUTHOR]

A simple strategy was adopted for the preparation of an antimicrobial natural rubber/graphene oxide (NR/GO) composite film modified through the use of zwitterionic polymer brushes. An NR/GO composite film with antibacterial properties was prepared using a water-based solution-casting method. The composited GO was dispersed uniformly in the NR matrix and compensated for mechanical loss in the process of modification. Based on the high bromination activity of α–H in the structure of cis-polyisoprene, the composite films were brominated on the surface through the use of N-bromosuccinimide (NBS) under the irradiation of a 40 W tungsten lamp. Polymerization was carried out on the brominated films using sulfobetaine methacrylate (SBMA) as a monomer via surface-initiated atom transfer radical polymerization (SI-ATRP). The NR/GO composite films modified using polymer brushes (PSBMAs) exhibited 99.99% antimicrobial activity for resistance to Escherichia coli and Staphylococcus aureus. A novel polymer modification strategy for NR composite materials was established effectively, and the enhanced antimicrobial properties expand the application prospects in the medical field. [ABSTRACT FROM AUTHOR]

Thymol, a plant-derived monoterpene phenol known for its broad biological activity, has often been incorporated into chitosan-based biomaterials to enhance therapeutic efficacy. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, we conducted a systematic literature review from 2018 to 2023, focusing on the biomedical implications of thymol-loaded chitosan systems. A review of databases, including PubMed, Scopus, and Web of Science was conducted using specific keywords and search criteria. Of the 90 articles, 12 were selected for the review. Thymol-loaded chitosan-based nanogels (TLCBS) showed improved antimicrobial properties, especially against multidrug-resistant bacterial antagonists. Innovations such as bipolymer nanocarriers and thymol impregnated with photosensitive chitosan micelles offer advanced bactericidal strategies and show potential for bone tissue regeneration and wound healing. The incorporation of thymol also improved drug delivery efficiency and biomechanical strength, especially when combined with poly(dimethylsiloxane) in chitosan–gelatin films. Thymol–chitosan combinations have also shown promising applications in oral delivery and periodontal treatment. This review highlights the synergy between thymol and chitosan in these products, which greatly enhances their therapeutic efficacy and highlights the novel use of essential oil components. It also highlights the novelty of the studies conducted, as well as their limitations and possible directions for the development of integrated substances of plant and animal origin in modern and advanced medical applications. [ABSTRACT FROM AUTHOR]

This study aims to develop new quaternary ammonium salt-based antimicrobial materials with good biocompatibility, biosafety, and strong antimicrobial properties that promote wound healing in infected wounds. First, four new quaternary ammonium salt antibacterial fibers (QASAF) are constructed: QASAF-C12, QASAF-C14, QASAF-C16, and QASAF-C18, with varying carbon chain lengths of C12, C14, C16, and C18, respectively. Then, their structure is characterized by proton nuclear magnetic resonance (NMR) analysis and their hemolytic and cytotoxic properties are also investigated. QASAFs are then evaluated for in vivo and in vitro antimicrobial performance against Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA). Finally, the effect of QASAF on promoting wound healing in infected wounds is evaluated using mouse wound models infected with S. aureus and MRSA. The obtained results suggest that QASAF is non-toxic to cells in the 25–125 µg/mL concentration range, is slightly hemolytic, has good biocompatibility, and has a biosafety profile. QASAF-C18 shows the best antibacterial performance against S. aureus with significant pro-healing effects on infected wounds. QASAF-C12 exhibits the best antibacterial performance against MRSA with significant pro-healing effects. The novel quaternary ammonium-based antimicrobial material provides a reference for developing antimicrobial and biocompatible wound dressings.

Light‐ induced polymeric 3D printing is becoming a well‐established fabrication method, showing manifold advantages such as control of the local chemistry of the manufactured devices. It can be considered a green technology, since the parts are produced when needed and with minimum amount of materials. In this work 3D printing is combined with another green technology, microwave‐assisted reaction, to fabricate objects of complex geometry with controllable surface properties, exploiting the presence of remaining functional groups on the surface of 3D printed specimens. In this context, surface functionalization with different amines is studied, optimizing formulations, reaction times, and avoiding surface deterioration. Then, two different applications are investigated. MW‐functionalized filter‐type structures have been tested against Staphylococcus aureus bacteria, showing high bactericidal activity on the surface along all areas of the complex‐shaped structure. Second, a fluidic chip composed of three separated channels is 3D printed, filled with different amine‐reactive dyes (dansyl and eosine derivatives), and made to react simultaneously. Complete and independent functionalization of the surface of the three channels is achieved only after 2 min of irradiation. This study demonstrates that light induced 3D printing and microwave‐induced chemistry can be used together effectively, and used to produce functional devices. [ABSTRACT FROM AUTHOR]

Modern consumption patterns have led to a surge in waste glass accumulating in municipal landfills, contributing to environmental pollution, especially in countries that do not have well-established recycling standards. While glass itself is 100% recyclable, the logistics and handling involved present significant challenges. Flint and amber-colored glass, often found in high quantities in municipal waste, can serve as valuable sources of raw materials. We propose an affordable route that requires just a thermal treatment of glass waste to obtain glass-based antimicrobial materials. The thermal treatment induces crystallized nanoregions, which are the primary factor responsible for the bactericidal effect of waste glass. As a result, coarse particles of flint waste glass that undergo thermal treatment at 720 °C show superior antimicrobial activity than amber waste glass. Glass-ceramic materials from flint waste glass, obtained by thermal treatment at 720 °C during 2 h, show antimicrobial activity against Escherichia coli after just 30 min of contact time. Laser-induced breakdown spectroscopy (LIBS) was employed to monitor the elemental composition of the glass waste. The obtained glass-ceramic material was structurally characterized by transmission electron microscopy, enabling the confirmation of the presence of nanocrystals embedded within the glass matrix.

Abstract Light‐ induced polymeric 3D printing is becoming a well‐established fabrication method, showing manifold advantages such as control of the local chemistry of the manufactured devices. It can be considered a green technology, since the parts are produced when needed and with minimum amount of materials. In this work 3D printing is combined with another green technology, microwave‐assisted reaction, to fabricate objects of complex geometry with controllable surface properties, exploiting the presence of remaining functional groups on the surface of 3D printed specimens. In this context, surface functionalization with different amines is studied, optimizing formulations, reaction times, and avoiding surface deterioration. Then, two different applications are investigated. MW‐functionalized filter‐type structures have been tested against Staphylococcus aureus bacteria, showing high bactericidal activity on the surface along all areas of the complex‐shaped structure. Second, a fluidic chip composed of three separated channels is 3D printed, filled with different amine‐reactive dyes (dansyl and eosine derivatives), and made to react simultaneously. Complete and independent functionalization of the surface of the three channels is achieved only after 2 min of irradiation. This study demonstrates that light induced 3D printing and microwave‐induced chemistry can be used together effectively, and used to produce functional devices.

Present worldwide difficulties in healthcare and the environment have motivated the investigation and research of novel materials in an effort to find novel techniques to address the current challenges and requirements. In particular, the use of nanomaterials has demonstrated a significant promise in the fight against bacterial infections and the problem of antibiotic resistance. Metal nanoparticles and carbon-based nanomaterials in particular have been highlighted for their exceptional abilities to inhibit many types of bacteria and pathogens. In order for these materials to be as effective as possible, synthetic techniques are crucial. Therefore, in this review article, we highlight some recent developments in the design and synthesis of various nanomaterials, including metal nanoparticles (e.g., Ag, Zn, or Cu), metal hybrid nanomaterials, and the synthesis of multi-metallic hybrid nanostructured materials. Following that, examples of these materials' applications in antimicrobial performance targeted at eradicating multi-drug resistant bacteria, material protection such as microbiologically influenced corrosion (MIC), or additives in construction materials have been described. [ABSTRACT FROM AUTHOR]

A simple strategy was adopted for the preparation of an antimicrobial natural rubber/graphene oxide (NR/GO) composite film modified through the use of zwitterionic polymer brushes. An NR/GO composite film with antibacterial properties was prepared using a water-based solution-casting method. The composited GO was dispersed uniformly in the NR matrix and compensated for mechanical loss in the process of modification. Based on the high bromination activity of α–H in the structure of cis-polyisoprene, the composite films were brominated on the surface through the use of N-bromosuccinimide (NBS) under the irradiation of a 40 W tungsten lamp. Polymerization was carried out on the brominated films using sulfobetaine methacrylate (SBMA) as a monomer via surface-initiated atom transfer radical polymerization (SI-ATRP). The NR/GO composite films modified using polymer brushes (PSBMAs) exhibited 99.99% antimicrobial activity for resistance to Escherichia coli and Staphylococcus aureus. A novel polymer modification strategy for NR composite materials was established effectively, and the enhanced antimicrobial properties expand the application prospects in the medical field.

Composites of magnesium oxychloride cement (MOC) functionalized with TiO 2 nanoparticles are proposed here as an alternative technology to maintain clean building surfaces from airborne pollutants and microorganisms. The MOC composites were characterized by different techniques such as XRD, FTIR, SEM, EDS, UV–Vis, compressive strength, and nanoindentation tests. According to the results, phase 3 (3 Mg(OH) 2 .MgCl 2 .8H 2 O) with needle-like morphology was the primary crystallized hydration product for the MOC composites. Also, the samples exhibited good mechanical properties and good light absorption, allowing them to activate under solar light irradiation. The self-cleaning efficiency of the MOC composites was evaluated by measuring the removal of three types of pollutants: methylene blue (MB), rhodamine B (RhB), and reactive black 5 (RB5), under two scenarios: natural sunlight and accelerated weathering conditions. The self-cleaning tests revealed outstanding efficiencies of the composites to remove MB (82%), RhB (88%), and RB5 (91%) under solar light and accelerated weathering tests. On the other hand, the antimicrobial activity was evaluated against E. coli (gram-negative) and S. aureus (gram-positive) under irradiation. The zone of inhibition (ZOI) showed diameters higher than 21 mm to E. coli for samples with 5% of TiO 2 or superior, revealing a high microbial inhibition of the gram-negative bacteria. Also, the structural and morphological stability of the MOC composites was confirmed after several cycles for the accelerating weathering tests, demonstrating their potential to be used outdoors to reduce environmental pollution. [ABSTRACT FROM AUTHOR]

Graphene, the world's thinnest two-dimensional (2D) carbon material, with the highly ordered and repeated atomic structure and its excellent properties such as mechanical, electrical, optical, chemical, and thermal properties, has been extensively studied and applied in materialogy, physics, biomedicine and other fields in recent years. In the case of biomedical applications, the advent of graphene-based materials (GBMs) has resulted in excellent biomedical materials with a wide range of applications. Compared with the published reviews of graphene-based biomedical materials, we systematically and comprehensively introduced the properties of graphene-based biomaterials from the perspective of biomedical applications. In addition, we introduced the structure and preparation methods of graphene and its derivatives, and summarized recent advances on GBMs in the biomedical field, including drug carriers, biosensors, tissue engineering, antimicrobial materials, and other forms of exploration for medical heating, radiation shielding, surgical suturing, and wastewater treatment. Finally, we discussed the current problems and challenges of GBMs and the prospect for the future development in the biomedical field. [ABSTRACT FROM AUTHOR]

Amino acid-based hydrogels have received widespread attention because of their wide range of sources, biodegradability, and biocompatibility. Despite considerable progress, the development of such hydrogels has been limited by critical problems such as bacterial infection and complex preparation. Herein, by using the non-toxic gluconolactone (GDL) to adjust the pH of the solution to induce the rapid self-assembly of N-[(benzyloxy)carbonyl]-L-tryptophan (ZW) to form a three-dimensional (3D) gel network, we developed a stable and effective self-assembled small-molecule hydrogel. Characterization assays and molecular dynamics studies indicate that π–π stacking and hydrogen bonding are the main drivers of self-assembly between ZW molecules. In vitro experiments further confirmed this material's sustained release properties, low cytotoxicity, and excellent antibacterial activity, particularly against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. This study provides a different and innovative perspective for the further development of antibacterial materials based on amino acid derivatives. [ABSTRACT FROM AUTHOR]

Bacterial infection is a common clinical disease. Antibiotics have saved countless lives since their discovery and are a powerful weapon in the fight against bacteria. However, with the widespread use of antibiotics, the problem of drug resistance now poses a great threat to human health. In recent years, studies have investigated approaches to combat bacterial resistance. Several antimicrobial materials and drug delivery systems have emerged as promising strategies. Nano-drug delivery systems for antibiotics can reduce the resistance to antibiotics and extend the lifespan of novel antibiotics, and they allow targeting drug delivery compared to conventional antibiotics. This review highlights the mechanistic insights of using different strategies to combat drug-resistant bacteria and summarizes the recent advancements in antimicrobial materials and drug delivery systems for different carriers. Furthermore, the fundamental properties of combating antimicrobial resistance are discussed, and the current challenges and future perspectives in this field are proposed. [ABSTRACT FROM AUTHOR]

In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound to the amino-pendant groups of three random copolymers, with different amounts of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the backbone. The P(MMA-ran-DMAEMA) copolymers have inherently bactericidal activity, due to the amino groups of DMAEMA and to the quaternized nitrogens bounded to BODIPY. Systems consisting of filter paper discs coated with copolymers conjugated to BODIPY were tested on two model microorganisms, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). On solid medium, irradiation with green light induced an antimicrobial effect, visible as a clear inhibition area around the coated disks. The system based on the copolymer with 43% DMAEMA and circa 0.70 wt/wt% of BODIPY was the most efficient in both bacterial species, and a selectivity for the Gram-positive model was observed, independently of the conjugated BODIPY. A residual antimicrobial activity was also observed after dark incubation, attributed to the inherently bactericidal properties of copolymers. [ABSTRACT FROM AUTHOR]

Multifunctional wound dressings deliver numerous complementary therapeutics in a single, easy‐to‐use material; however, incompatibilities between additives and the inability to control spatial loading (i.e., surface vs. bulk) sometimes complicate material design and inhibit the use of all available beneficial additives. 3D printing affords the capability to fabricate polymeric wound dressings in unique and individually specific morphologies, as well as the ability to control spatial composition of the multifunctional wound dressing to overcome some of the aforementioned shortfalls from traditional material fabrication techniques. We demonstrate 3D printing as a viable tool to place additives from novel class of antimicrobials, cyclic peptides, in a UV curable, and multifunctional (absorbent and hemostatic) microporous polymer. Microscopic and material characterization confirmed loading of cyclic peptide and microporous architecture was unaffected by peptide loading and the extrusion 3D printing process. Cytotoxic evaluations indicate toxicity of peptide additives toward prokaryotic and eukaryotic cells and highlight the importance of spatial control afforded by 3D printing. The robustness of high internal phase emulsion templating and 3D printing was confirmed with antimicrobial assays that showed antimicrobial efficacy of the cyclic peptides were maintained and unaffected by polymerization and processing. [ABSTRACT FROM AUTHOR]

Hybrid polysiloxanes and polysilsesquioxanes grafted with naturally occurring bioactive phytochemicals: eugenol and linalool, were synthesized and investigated with regard to their structure and properties. The two series of materials, differing in the type of inorganic structure and the content of active groups, were coated onto the surface of glass plates, and their antibiofilm activities against bacteria Aeromonas hydrophila were assessed by luminometry and fluorescence microscopy. Bioactivity was correlated with specific properties of the hybrid coatings (chemical structure, surface free energy and adhesiveness). The functionalized polysilsesquioxanes exhibited the most favorable anti-adhesive effects. Cell adhesion after 6 days of incubation, expressed as RLU/cm2, was significantly reduced (44 and 67 for, respectively, Z-E-100 and Z-L-100, compared to 517 for the control glass carrier). The surface stickiness of polysiloxane films deteriorated their anti-adhesion properties, despite the presence of a large amount of bioactive species. [ABSTRACT FROM AUTHOR]

Polymeric nanoparticles (NPs) present some ideal properties as biomedical nanocarriers for targeted drug delivery such as enhanced translocation through body barriers. Biopolymers, such as polyhydroxyalkanoates (PHAs) are gaining attention as nanocarrier biomaterials due to their inherent biocompatibility, biodegradability, and ability to be vehiculized through hydrophobic media, such as the lung surfactant (LS). Upon colonization of the lung alveoli, below the LS layer, Streptococcus pneumoniae, causes community-acquired pneumonia, a severe respiratory condition. In this work, we convert PHA NPs into an antimicrobial material by the immobilization of an enzybiotic, an antimicrobial enzyme, via a minimal PHA affinity tag. We first produced the fusion protein M711, comprising the minimized PHA affinity tag, MinP, and the enzybiotic Cpl-711, which specifically targets S. pneumoniae. Then, a PHA nanoparticulate suspension with adequate physicochemical properties for pulmonary delivery was formulated, and NPs were decorated with M711. Finally, we assessed the antipneumococcal activity of the nanosystem against planktonic and biofilm forms of S. pneumoniae. The resulting system displayed sustained antimicrobial activity against both, free and sessile cells, confirming that tag-mediated immobilization of enzybiotics on PHAs is a promising platform for bioactive antimicrobial functionalization.

Thymol, a plant-derived monoterpene phenol known for its broad biological activity, has often been incorporated into chitosan-based biomaterials to enhance therapeutic efficacy. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, we conducted a systematic literature review from 2018 to 2023, focusing on the biomedical implications of thymol-loaded chitosan systems. A review of databases, including PubMed, Scopus, and Web of Science was conducted using specific keywords and search criteria. Of the 90 articles, 12 were selected for the review. Thymol-loaded chitosan-based nanogels (TLCBS) showed improved antimicrobial properties, especially against multidrug-resistant bacterial antagonists. Innovations such as bipolymer nanocarriers and thymol impregnated with photosensitive chitosan micelles offer advanced bactericidal strategies and show potential for bone tissue regeneration and wound healing. The incorporation of thymol also improved drug delivery efficiency and biomechanical strength, especially when combined with poly(dimethylsiloxane) in chitosan–gelatin films. Thymol–chitosan combinations have also shown promising applications in oral delivery and periodontal treatment. This review highlights the synergy between thymol and chitosan in these products, which greatly enhances their therapeutic efficacy and highlights the novel use of essential oil components. It also highlights the novelty of the studies conducted, as well as their limitations and possible directions for the development of integrated substances of plant and animal origin in modern and advanced medical applications.

With the increasing trend of hard-to-treat microbial infections, including multiresistant nosocomial infections, food-related outbreaks, and the rapid spread of potentially infectious microbes in the common spaces of densely populated areas, awareness of the importance of proper systemic hygiene practices has increased [...]

Molybdenum disulfide (MoS2) nanoparticles, obtained from liquid phase exfoliation in the presence of chitosan, were melt mixed with a linear low‐density polyethylene (LLDPE) matrix to produce novel antimicrobial active packaging materials. The LLDPE/MoS2 composites presented exfoliated nanoparticles forming aggregates that are well dispersed in the polymer matrix. These 2D‐layered MoS2 nanoparticles at concentrations of 0.5, 1.0, and 3.0 wt% rendered several functionalities to the LLDPE, as for example an antimicrobial behavior against Salmonella typhi and Listeria monocytogenes bacteria that can be explained not only by the photoactivity of the filler but also by changes in the composite surface. For instance, the composites presented a reduction in the water contact angle (i.e., an increased hydrophilicity) and relevant changes in the surface topography (i.e., reduced roughness) as compared with pure LLDPE. Regarding the barrier properties, while MoS2 dramatically increased the water vapor permeation (WVP) of the polymer matrix, until 15 times for composite with 3.0 wt% of filler, the oxygen permeation decreased around 25%. All these novel functionalities in the nanocomposites were obtained without significantly affecting the tensile mechanical properties of the pure LLDPE matrix. These results show that MoS2 is a promising filler for the development of antibacterial active packaging films with behaviors as similar as other 2D‐layered fillers such as graphene derivatives. [ABSTRACT FROM AUTHOR]

Annually, antimicrobial-resistant infections-related mortality worldwide accelerates due to the increased use of antibiotics during the coronavirus pandemic and the antimicrobial resistance, which grows exponentially, and disproportionately to the current rate of development of new antibiotics. Nanoparticles can be an alternative to the current therapeutic approach against multi-drug resistance microorganisms caused infections. The motivation behind this work was to find a superior antibacterial nanomaterial, which can be efficient, biocompatible, and stable in time. This study evaluated the antibacterial activity of ZnO-based nanomaterials with different morphologies, synthesized through the solvothermal method and further modified with Au nanoparticles through wet chemical reduction. The structure, crystallinity, and morphology of ZnO and ZnO/Au nanomaterials have been investigated with XRD, SEM, TEM, DLS, and FTIR spectroscopy. The antibacterial effect of unmodified ZnO and ZnO/Au nanomaterials against Escherichia coli and Staphylococcus aureus was investigated through disc diffusion and tetrazolium/formazan (TTC) assays. The results showed that the proposed nanomaterials exhibited significant antibacterial effects on the Gram-positive and Gram-negative bacteria. Furthermore, ZnO nanorods with diameters smaller than 50 nm showed better antibacterial activity than ZnO nanorods with larger dimensions. The antibacterial efficiency against Escherichia coli and Staphylococcus aureus improved considerably by adding 0.2% (w/w) Au to ZnO nanorods. The results indicated the new materials' potential for antibacterial applications. [ABSTRACT FROM AUTHOR]

Present worldwide difficulties in healthcare and the environment have motivated the investigation and research of novel materials in an effort to find novel techniques to address the current challenges and requirements. In particular, the use of nanomaterials has demonstrated a significant promise in the fight against bacterial infections and the problem of antibiotic resistance. Metal nanoparticles and carbon-based nanomaterials in particular have been highlighted for their exceptional abilities to inhibit many types of bacteria and pathogens. In order for these materials to be as effective as possible, synthetic techniques are crucial. Therefore, in this review article, we highlight some recent developments in the design and synthesis of various nanomaterials, including metal nanoparticles (e.g., Ag, Zn, or Cu), metal hybrid nanomaterials, and the synthesis of multi-metallic hybrid nanostructured materials. Following that, examples of these materials’ applications in antimicrobial performance targeted at eradicating multi-drug resistant bacteria, material protection such as microbiologically influenced corrosion (MIC), or additives in construction materials have been described.

Bacterial keratitis (BK) is an acute infection of the cornea, accompanied by uneven epithelium boundaries with stromal ulceration, potentially resulting in vision loss. Topical antibiotic is the regular treatment for BK. However, the incidence rate of multidrug-resistant bacteria limits the application of traditional antibiotics. Therefore, a cationic aggregation-induced emission luminogens (AIEgens) named TTVP is utilized for the treatment of BK. TTVP showed no obvious cytotoxicity in maintaining the normal cell morphology and viability under a limited concentration, and revealed the ability to selectively combine with bacteria in normal ocular environment. After light irradiation, TTVP produced reactive oxygen species (ROS), thus exerting efficient antibacterial ability in vitro. What’s more, in rat models of Staphylococcus aureus (S. aureus) infection, the therapeutic intervention of TTVP lessens the degree of corneal opacity and inflammatory infiltration, limiting the spread of inflammation. Besides, TTVP manifested superior antibacterial efficacy than levofloxacin in acute BK, endowing its better vision salvage ability than conventional method. This research demonstrates the efficacy and advantages of TTVP as a photodynamic drug in the treatment of BK and represents its promise in clinical application of ocular infections.

The use of electrospun meshes has been proposed as highly efficient protective equipment to prevent respiratory infections. Those infections can result from the activity of micro-organisms and other small dust particles, such as those resulting from air pollution, that impair the respiratory tract, induce cellular damage and compromise breathing capacity. Therefore, electrospun meshes can contribute to promoting air-breathing quality and controlling the spread of such epidemic-disrupting agents due to their intrinsic characteristics, namely, low pore size, and high porosity and surface area. In this review, the mechanisms behind the pathogenesis of several stressors of the respiratory system are covered as well as the strategies adopted to inhibit their action. The main goal is to discuss the performance of antimicrobial electrospun nanofibers by comparing the results already reported in the literature. Further, the main aspects of the certification of filtering systems are highlighted, and the expected technology developments in the industry are also discussed. [ABSTRACT FROM AUTHOR]

Metals play an essential role in biochemistry, and the use of metals for antimicrobial applications has been well studied. Biomaterials incorporating copper and silver demonstrated high antimicrobial activity while maintaining good cytocompatibility. In this overview, nanostructure processing is underscored as a method to overcome the shortcomings of conventional bioceramics. Restructuring crystalline structures at the nanoscale make it less susceptible to brittle fracture. Furthermore, the bioactivity of the material is significantly improved through nanoscale surface modifications such as coatings. The effectiveness of nanostructured biomaterials featuring copper and silver in combatting bacterial attachment and proliferation is described. Nanoscale copper-containing stainless steel achieved antimicrobial activity by disrupting bacterial metabolism and damaging bacterial membranes while providing a conducive environment for cellular proliferation. Copper-containing stainless steels can be used to prevent marine corrosion, food preservation and combat implant-related infections. It is envisaged that future antimicrobial strategies will continue to feature copper and silver nanostructured biomaterials prominently. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) has recently been attracting attention as a highly efficient method to process antimicrobial materials with scalable sizes and tunable properties. In this work, freestanding graphene papers are systematically investigated to study their process- and structure-dependent antibacterial activities against both Gram-positive and Gram-negative species. In addition to microscopy analyses for qualitative discussion of live and dead cells, a colony counting assay is applied to precisely quantify the loss of viability of bacteria treated by various laser-induced graphene papers (LIGPs) with tunable microstructures. Remarkably, the 1.25 W-processed LIGPs (LIGP-1.25 W) exhibit the highest reduction rate of 92.8% for Escherichia coli (E. coli) and 95.2% for Staphylococcus aureus (S. aureus), compared with LIGPs processed under 0.75 W (LIGP-0.75 W) and 1.75 W (LIGP-1.75 W). In addition to proving the combined membrane stress and reactive oxygen species (ROS)-independent oxidative stress-related mechanisms, the specific interconnected open-cell network with the highest specific surface area (171.6 m2/g) is found to be the determinant with fruitful bacteria trapping sites. Finally, corrosion resistance test is applied for demonstrating the capability of LIGPs for protecting the aluminum alloy sheet against immersion invasion of E. coli suspension up to 3 weeks, suggesting their great potentiality for facilitating advanced environmental protection activities. [ABSTRACT FROM AUTHOR]

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

This study aims to develop new quaternary ammonium salt-based antimicrobial materials with good biocompatibility, biosafety, and strong antimicrobial properties that promote wound healing in infected wounds. First, four new quaternary ammonium salt antibacterial fibers (QASAF) are constructed: QASAF-C12, QASAF-C14, QASAF-C16, and QASAF-C18, with varying carbon chain lengths of C12, C14, C16, and C18, respectively. Then, their structure is characterized by proton nuclear magnetic resonance (NMR) analysis and their hemolytic and cytotoxic properties are also investigated. QASAFs are then evaluated for in vivo and in vitro antimicrobial performance against Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA). Finally, the effect of QASAF on promoting wound healing in infected wounds is evaluated using mouse wound models infected with S. aureus and MRSA. The obtained results suggest that QASAF is non-toxic to cells in the 25–125 µg/mL concentration range, is slightly hemolytic, has good biocompatibility, and has a biosafety profile. QASAF-C18 shows the best antibacterial performance against S. aureus with significant pro-healing effects on infected wounds. QASAF-C12 exhibits the best antibacterial performance against MRSA with significant pro-healing effects. The novel quaternary ammonium-based antimicrobial material provides a reference for developing antimicrobial and biocompatible wound dressings. [ABSTRACT FROM AUTHOR]

Amino acid-based hydrogels have received widespread attention because of their wide range of sources, biodegradability, and biocompatibility. Despite considerable progress, the development of such hydrogels has been limited by critical problems such as bacterial infection and complex preparation. Herein, by using the non-toxic gluconolactone (GDL) to adjust the pH of the solution to induce the rapid self-assembly of N-[(benzyloxy)carbonyl]-L-tryptophan (ZW) to form a three-dimensional (3D) gel network, we developed a stable and effective self-assembled small-molecule hydrogel. Characterization assays and molecular dynamics studies indicate that π–π stacking and hydrogen bonding are the main drivers of self-assembly between ZW molecules. In vitro experiments further confirmed this material’s sustained release properties, low cytotoxicity, and excellent antibacterial activity, particularly against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. This study provides a different and innovative perspective for the further development of antibacterial materials based on amino acid derivatives.

Bacterial infection is a common clinical disease. Antibiotics have saved countless lives since their discovery and are a powerful weapon in the fight against bacteria. However, with the widespread use of antibiotics, the problem of drug resistance now poses a great threat to human health. In recent years, studies have investigated approaches to combat bacterial resistance. Several antimicrobial materials and drug delivery systems have emerged as promising strategies. Nano-drug delivery systems for antibiotics can reduce the resistance to antibiotics and extend the lifespan of novel antibiotics, and they allow targeting drug delivery compared to conventional antibiotics. This review highlights the mechanistic insights of using different strategies to combat drug-resistant bacteria and summarizes the recent advancements in antimicrobial materials and drug delivery systems for different carriers. Furthermore, the fundamental properties of combating antimicrobial resistance are discussed, and the current challenges and future perspectives in this field are proposed.

In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound to the amino-pendant groups of three random copolymers, with different amounts of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the backbone. The P(MMA-ran-DMAEMA) copolymers have inherently bactericidal activity, due to the amino groups of DMAEMA and to the quaternized nitrogens bounded to BODIPY. Systems consisting of filter paper discs coated with copolymers conjugated to BODIPY were tested on two model microorganisms, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). On solid medium, irradiation with green light induced an antimicrobial effect, visible as a clear inhibition area around the coated disks. The system based on the copolymer with 43% DMAEMA and circa 0.70 wt/wt% of BODIPY was the most efficient in both bacterial species, and a selectivity for the Gram-positive model was observed, independently of the conjugated BODIPY. A residual antimicrobial activity was also observed after dark incubation, attributed to the inherently bactericidal properties of copolymers.

Hybrid polysiloxanes and polysilsesquioxanes grafted with naturally occurring bioactive phytochemicals: eugenol and linalool, were synthesized and investigated with regard to their structure and properties. The two series of materials, differing in the type of inorganic structure and the content of active groups, were coated onto the surface of glass plates, and their antibiofilm activities against bacteria Aeromonas hydrophila were assessed by luminometry and fluorescence microscopy. Bioactivity was correlated with specific properties of the hybrid coatings (chemical structure, surface free energy and adhesiveness). The functionalized polysilsesquioxanes exhibited the most favorable anti-adhesive effects. Cell adhesion after 6 days of incubation, expressed as RLU/cm2, was significantly reduced (44 and 67 for, respectively, Z-E-100 and Z-L-100, compared to 517 for the control glass carrier). The surface stickiness of polysiloxane films deteriorated their anti-adhesion properties, despite the presence of a large amount of bioactive species.

Sustainable solutions on fabricating and using a face mask to block the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spread during this coronavirus pandemic of 2019 (COVID‐19) are required as society is directed by the World Health Organization (WHO) toward wearing it, resulting in an increasingly huge demand with over 4 000 000 000 masks used per day globally. Herein, various new mask technologies and advanced materials are reviewed to deal with critical shortages, cross‐infection, and secondary transmission risk of masks. A number of countries have used cloth masks and 3D‐printed masks as substitutes, whose filtration efficiencies can be improved by using nanofibers or mixing other polymers into them. Since 2020, researchers continue to improve the performance of masks by adding various functionalities, for example using metal nanoparticles and herbal extracts to inactivate pathogens, using graphene to make masks photothermal and superhydrophobic, and using triboelectric nanogenerator (TENG) to prolong mask lifetime. The recent advances in material technology have led to the development of antimicrobial coatings, which are introduced in this review. When incorporated into masks, these advanced materials and technologies can aid in the prevention of secondary transmission of the virus. [ABSTRACT FROM AUTHOR]

Abstract Sustainable solutions on fabricating and using a face mask to block the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spread during this coronavirus pandemic of 2019 (COVID‐19) are required as society is directed by the World Health Organization (WHO) toward wearing it, resulting in an increasingly huge demand with over 4 000 000 000 masks used per day globally. Herein, various new mask technologies and advanced materials are reviewed to deal with critical shortages, cross‐infection, and secondary transmission risk of masks. A number of countries have used cloth masks and 3D‐printed masks as substitutes, whose filtration efficiencies can be improved by using nanofibers or mixing other polymers into them. Since 2020, researchers continue to improve the performance of masks by adding various functionalities, for example using metal nanoparticles and herbal extracts to inactivate pathogens, using graphene to make masks photothermal and superhydrophobic, and using triboelectric nanogenerator (TENG) to prolong mask lifetime. The recent advances in material technology have led to the development of antimicrobial coatings, which are introduced in this review. When incorporated into masks, these advanced materials and technologies can aid in the prevention of secondary transmission of the virus.

To help assess whether a potentially antimicrobial material, surface, or coating provides antimicrobial efficacy, a number of standardised test methods have been developed internationally. Ideally, these methods should generate data that supports the materials efficacy when deployed in the intended end-use application. These methods can be categorised based on their methodological approach such as suspension tests, agar plate/zone diffusion tests, surface inoculation tests, surface growth tests or surface adhesion tests. To support those interested in antimicrobial coating efficacy, this review brings together an exhaustive list of methods (for porous and non-porous materials), exploring the methodological and environmental parameters used to quantify antibacterial, antifungal, or antiviral activity. This analysis demonstrates that antimicrobial efficacy methods that test either fungi or viruses are generally lacking, whilst methods that test bacteria, fungi and viruses are not designed to simulate end-use/lack realistic conditions. As such, a number of applications for antimicrobial activity across medical touch screens, medical textiles and gloves and transport seat textiles are explored as example applications, providing guidance on modifications to existing methods that may better simulate the intended end-use of antimicrobial materials., Competing Interests: At the time of publication, J.R. is Deputy Editor in Chief of Access Microbiology., (Copyright © 2024 The Authors.)

This document discusses the importance of proper hygiene practices in preventing the transmission of pathogens through contaminated surfaces. It suggests that antimicrobial surface coatings could be a potential solution to reduce the spread of infections. The most commonly used active agents in these coatings are silver, copper, titanium dioxide, and zinc. However, there is concern about the emergence of antimicrobial resistance and the potential link between metal resistance and antibiotic resistance. The document proposes a strategy to determine the safety and sustainability of antimicrobial surfaces in terms of their potential to induce resistance or tolerance. The authors believe that this framework can ensure the long-term safety and effectiveness of antimicrobial materials. [Extracted from the article]

Zinc has been widely utilized as an antimicrobial material, often in the form of complexes or zinc oxide nanoparticles. The efficacy of zinc complexes are often due to the synergistic effect of both the zinc ions and the attached organic ligands. In contrast, the nanoparticle effect of ZnO, and the photocatalytic generation of reactive oxygen species (ROS) has been postulated to be the effective mechanism of ZnO as a biocide. Recently, new forms of zinc‐based biocidal materials have been reported with distinct antimicrobial mechanisms. This minireview summarizes these recent advances, including zinc‐based nano‐arrays, MOF‐based ROS release and zinc composites that can self‐generate ROS. [ABSTRACT FROM AUTHOR]

Annually, antimicrobial-resistant infections-related mortality worldwide accelerates due to the increased use of antibiotics during the coronavirus pandemic and the antimicrobial resistance, which grows exponentially, and disproportionately to the current rate of development of new antibiotics. Nanoparticles can be an alternative to the current therapeutic approach against multi-drug resistance microorganisms caused infections. The motivation behind this work was to find a superior antibacterial nanomaterial, which can be efficient, biocompatible, and stable in time. This study evaluated the antibacterial activity of ZnO-based nanomaterials with different morphologies, synthesized through the solvothermal method and further modified with Au nanoparticles through wet chemical reduction. The structure, crystallinity, and morphology of ZnO and ZnO/Au nanomaterials have been investigated with XRD, SEM, TEM, DLS, and FTIR spectroscopy. The antibacterial effect of unmodified ZnO and ZnO/Au nanomaterials against Escherichia coli and Staphylococcus aureus was investigated through disc diffusion and tetrazolium/formazan (TTC) assays. The results showed that the proposed nanomaterials exhibited significant antibacterial effects on the Gram-positive and Gram-negative bacteria. Furthermore, ZnO nanorods with diameters smaller than 50 nm showed better antibacterial activity than ZnO nanorods with larger dimensions. The antibacterial efficiency against Escherichia coli and Staphylococcus aureus improved considerably by adding 0.2% (w/w) Au to ZnO nanorods. The results indicated the new materials’ potential for antibacterial applications.

The use of electrospun meshes has been proposed as highly efficient protective equipment to prevent respiratory infections. Those infections can result from the activity of micro-organisms and other small dust particles, such as those resulting from air pollution, that impair the respiratory tract, induce cellular damage and compromise breathing capacity. Therefore, electrospun meshes can contribute to promoting air-breathing quality and controlling the spread of such epidemic-disrupting agents due to their intrinsic characteristics, namely, low pore size, and high porosity and surface area. In this review, the mechanisms behind the pathogenesis of several stressors of the respiratory system are covered as well as the strategies adopted to inhibit their action. The main goal is to discuss the performance of antimicrobial electrospun nanofibers by comparing the results already reported in the literature. Further, the main aspects of the certification of filtering systems are highlighted, and the expected technology developments in the industry are also discussed.

The utilization of lipids is presently in the spotlight of food industry as they are one of novel renewable and sustainable raw materials. Lipids derived materials are considered as a promising alternate to petro‐based polymers as they are sustainable, biorenewable, biodegradable, and environmentally benign. These unique attributes draw the attention of scientific community for the use of lipids in food packaging applications with a potential to compete with fossil fuel derived polymers. This paper reviews recent advances in the use of lipids and their effect on the barrier, antimicrobial, antioxidant, and mechanical properties of films, coating and nanocomposites for food packaging applications. Modification of lipids and its chemical interactions with other biopolymers during processing for the synthesis of different materials are also discussed. Global patents and research trend in use of lipids for the preparation of biocomposites are also described. The role of lipids in the circular economy is highlighted and life cycle assessment of lipids derived products is outlined with examples. The review is concluded with synoptic view of existing and forthcoming potential use of lipids in various food packaging applications. [ABSTRACT FROM AUTHOR]

The novel coronavirus designated as SARS-CoV-2 has risen the first pandemic caused by coronavirus and by November 26, 2020 is responsible for more than 1,410 million deaths. This scenario evidences that despite previous pandemics and epidemics in the world’s history, the current worldwide measures to contain and to mitigate viruses’ outbreaks are still disabled and insufficient. Therefore, this perspective reinforces the need for new and practical approaches for antiviral material developments and presents current technologies and its advances in this field of research focusing especially in surface materials since it is one of the most common interaction pathways. Furthermore, the roll that nanotechnology has been playing in the combat of viruses as well as the mechanisms that science has been discovering to inactivate these pathogenic microorganisms is presented. Finally, we suggest introducing new legislation and norms rather more specified on virucidal agents (materials and devices) than bactericidal ones in human environments such as hospitals, nursing homes, buses, and shopping centers to mitigate the current and future virus-based pandemics and epidemics.

The use of antibacterial surfaces is an effective way to reduce exposure to pathogens and therefore infections. Several methods to fabricate antibacterial surfaces using surface modification methods as well as a bactericidal agent incorporation inside materials have been reported. However, in most cases the factors affecting the antibacterial behavior of a surface are not discussed in detail. Here, a comparative study on the antibacterial properties of surfaces with different characteristics against Gram‐negative bacteria (Escherichia coli) under dynamic conditions is presented, aiming to unravel the interplay among the most important factors when realizing an antibacterial surface, that is, surface morphology, wetting properties, and the use of a bactericidal agent. Significant bactericidal efficacy for the micro‐nanotextured, superhydrophilic surfaces is demonstrated, possibly due to a mechanical killing induced by the interaction of bacteria with the micro‐nanotopography. On the other hand, superhydrophobic surfaces without any bactericidal agent exhibit low interaction with the bacteria containing medium and therefore lower bactericidal action, whereas superhydrophobic surfaces with a bactericidal agent exhibit extreme non‐wetting properties and rapid bactericidal effect through release of Cu particles. Finally, the role of the hydrophobic coating as barrier against uncontrolled release of the bactericidal agent when deposited as top layer is also showcased. [ABSTRACT FROM AUTHOR]

Microbial contamination of indoor environmental surfaces is a common source for infections. Therefore, bio-deterioration in buildings indoor materials is really important to avoid, due to the negative impact on human health. Consequently, functionalized and sustainable materials are being intensively studied to control the microbial colonization. Firstly, it was possible to obtain silica samples by the sol-gel method with the addition of sunflower residues in the form of ashes together with silver or copper salt to produce antimicrobials solids. Secondly, the synthesized solids were characterized by different techniques. TEM analyses confirmed the successful inclusion of silver and copper nanoparticles into the silica framework mainly spherical in shape, and small size. Both silver and copper as antimicrobial agents reduce the potential for cross-contamination to occur, as it is effective against a wide range of microorganisms, by the addition of ashes into the samples improved the antifungal activity of the solids against both fungal strains tested, Chaetomium globosum and Alternaria alternata.

Features of the plastic deformation of poly(p-dioxanone) fibers in air were studied. The neck propagation in the deformation speed range 0.2–15 mm/min was shown to occur in the self-excited oscillation mode. It was detected for the first time that this process is accompanied by the formation of areas with an open-pore structure. Impregnation of the fibers with brilliant green with the penetration of the die from the solution into the pores produces fibers with antimicrobial properties against the fungal culture of Candida albicans. [ABSTRACT FROM AUTHOR]

The study objects were nanoparticles of zinc oxide and titanium dioxide. The aim was to investigate the dependence of antimicrobial activity of solutions with nanosize powders of different particle sizes and concentrations. It has been established that nanoparticles of zinc oxide (size 2−4 nm and 5−7 nm) at a suspension concentration varying from 0.01% to 0.25% exhibit effective antifungal and antibacterial properties in relation to the eight types of microorganisms most commonly affecting internal surface of building structures (the concentration of microorganisms decreases by 2–3 orders of magnitude depending on their type). Nanoparticles of titanium (5−15 nm and 10−20 nm) demonstrated low antimicrobial activity.