Excellent Antibacterial Effect Research Articles

Photothermal antibacterial MoS2 composited chitosan hydrogel for infectious wound healing

Pathological bacterial infection poses a serious threat to public health security. The excessive use of antibiotics has resulted in a serious decline in treatment effect and bacterial resistance. For the treatment of infected wounds, we compounded dopamine-assisted exfoliated molybdenum disulfide (MoS2@PDA) into lipoic acid modified chitosan (LAMC) to obtain a composite hydrogel dressing (LAMC-MoS2@PDA). LAMC-MoS2@PDA hydrogels exhibited excellent photothermal conversion ability and the LAMC-MoS2@PDA2 group (0.3 wt%) has a photothermal conversion efficiency of 26.29 %. Meanwhile, they showed good biocompatibility and ROS scavenging activity in vitro. Photothermal therapy usually utilizes photothermal agents to convert near-infrared light into heat energy for bacterial cell membrane destruction and bacterial protein inactivation. Under the near-infrared light irradiation, the antibacterial ratio of LAMC-MoS2@PDA hydrogels against Staphylococcus aureus and Escherichia coli reached nearly 100 %, and the morphology of the bacteria showed obvious contraction and cleavage. The hydrogels also showed an excellent antibacterial effect and wound healing promotion in the infected wound of rats. In particular, the LAMC-MoS2@PDA2 (+) group (with NIR) showed almost complete wound closure after 14 days, indicating that the LAMC-MoS2@PDA hydrogels have great potential in clinical anti-infected treatment.

PCL/Yam Polysaccharide nanofibrous membranes loaded with self-assembled HP-β-CD/ECG inclusion complexes for food packaging

In this study, Polycaprolactone (PCL)/Yam Polysaccharide (YP) fiber membranes loaded the ultrasound-mediated assembly of 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD)/Epicatechin gallate (ECG) inclusion complexes were prepared by electrospinning technology for food packaging. Morphology, infrared spectroscopy and X-ray diffraction results showed that the inclusion complexes were successfully assembled. With the addition of inclusion complexes, the average diameter of the fibers increased from 2480.96 to 10179.12 nm, the crystallinity decreased, the thermal stability improved, the hydrophilicity enhanced, and the water vapor permeability enhanced. Meanwhile, thermogravimetry and differential scanning calorimetry results showed that the inclusion complexes formed hydrogen bonds between the fibers, which improved the thermal stability, but the mechanical behavior suffered a certain loss. In addition, the fiber membrane could continuously release ECG within 240 h, which showed excellent antibacterial effects both in vitro and in vivo. These results indicated that the fiber film developed based on electrospinning had a broad application prospect in food packaging.

Preparation and characterization of ι-carrageenan nanocomposite hydrogels with dual anti-HPV and anti-bacterial activities

Sexually transmitted diseases (STDs) are usually caused by co-infections of bacteria and viruses. However, there is a lack of products that possess both antibacterial and antiviral activities without using chemical drugs. Here, we developed a carrageenan silver nanoparticle composite hydrogel (IC-AgNPs-Gel) based on the antiviral activity of iota carrageenan (IC) and the antibacterial effect of silver nanoparticles (AgNPs) to prevent STDs. IC-AgNPs-Gel showed excellent biocompatibility, hemostasis, antibacterial and antiviral effects. IC-AgNPs-Gel not only effectively prevented S. aureus, E. coli, P. aeruginosa, and C. albicans without using antibiotics, but also significantly inhibited human papilloma virus (HPV)-16 and HPV-6 without using chemotherapy drugs. Moreover, IC-AgNPs-Gel showed the effects of accelerating infected wound healing and reducing inflammation in a rat wound model infected with S. aureus. Therefore, the multifunctional hydrogel shows great potential application prospect in preventing STDs.

Development of Active Antibacterial CEO/CS@PLA Nonwovens and the Application on Food Preservation.

The biodegradable activity antibacterial materials have been widely applied on food preservation because they not only protect foods from pathogenic attacks but also relieve environmental pollution. Biodegradable melt-blown nonwovens (MB) have several advantages over the other materials in terms of a simpler and more environmentally friendly fabrication process, higher specific surface area, and lower cost. Herein, polylactic acid (PLA) MB is first modified by polydopamine (PDA) to activate the surface. Then, chitosan (CS) and cinnamon essential oil (CEO) are used to decorate the surface of the modified PLA MB via a simple one-pot method to prepare CEO/CS@PLA MB with different CEO contents. Compared with PLA MB, CEO/CS@PLA MB had a rougher surface and larger average fiber diameter, while the average pore diameter and air permeability reduced. The input of CEO led to a decrease in the tensile strength of CEO/CS@PLA MB and an obvious increase in the elongation at break. The combination of CS and CEO shows excellent synergistic antibacterial effect. The antibacterial efficiencies of CEO/CS@PLA MB against Escherichia coli and Staphylococcus aureus enhance with the increase of the CEO content. When the weight ratio of CS to CEO is 1:2, the antibacterial efficiencies of CEO2/CS@PLA MB against E. coli and S. aureus are 99.98 and 99.99%, respectively. When being applied to the preservation of fresh strawberry, CEO2/CS@PLA MB can effectively inhibit the microbial growth in strawberry and reduce decay, which extends the shelf time of strawberry.

Bone-Adhesive Hydrogel for Effective Inhibition of M. tuberculosis and Osteoblast Regeneration.

Currently, bone tuberculosis (TB) treatment largely involves lifelong drug prescriptions and surgical intervention, resulting in poor quality of life for patients. Therefore, the fabrication of injectable scaffolds to form a solid framework around the defective bone region is gaining importance over the extensive use of antimicrobial inhibitors. Herein, we synthesized a novel bone-adhesive and thermoresponsive hydrogel via conjugation of poly(N-isopropylacrylamide-co-glycidyl methacrylate) (PNIPAM-co-GMA) and cysteine (CYS). Thiolation of the polymer enables chemical cross-linking with the bone glycoprotein, enhancing bone adhesion and permitting control of scaffold retention time. The PNIPAM-co-GMA-CYS hydrogel shows higher cross-linking behavior at 37 °C, forms a strong gel in 260 s, and has 151 kPa adhesion strength on cortical bone. The lead compounds 5-methyl-5H-[1,2,4]triazino[5,6-b]indole-3-thiol (MTIT) and N-tert-butyl-4-methyl-6-(5-methyl-5H-[1,2,4]triazino[5,6-b]indol-3-ylthio)pyrimidin-2-amine (TMTIPA) were identified by a high-throughput screening method. Effective MTIT and TMTIPA are encapsulated in bone-adhesive hydrogel separately, and both have a high release rate above >70% in 180 h. The MTIT- and TMTIPA-loaded PNIPAM-co-GMA-CYS showed an excellent bactericidal effect, reducing the relative intracellular bacterial survival in macrophages. Furthermore, the as-synthesized hydrogel has outstanding mechanical and biocompatibility properties to become a bone-replacing material and provide support to promote bone repair. This work presents a novel bone-adhesive PNIPAM-co-GMA-CYS for the sustained release of lead compounds toward promising alternative bone TB treatment.

Preparation, characterization and activity evaluation of Spirulina-chitooligosaccharides capable of inhibiting biofilms

The biofilms formed by pathogenic microorganisms seriously threaten human health and significantly enhance drug resistance, which urgently call for developing drugs specifically targeting on biofilms. Chitooligosaccharides extracted from shrimp and crab shells are natural alkaline oligosaccharides with excellent antibacterial effects. Nevertheless, their inhibition efficacy on biofilms still needs to be improved. Spirulina (SP) is a microalga with negatively charged surface, and its spiral structure facilitates colonization in the depth of the biofilm. Therefore, the complex of Spirulina and chitooligosaccharides may play a synergistic role in killing pathogens in the depth of biofilm. This research first screened chitooligosaccharides with significant bactericidal effects. Subsequently, Spirulina@Chitooligosaccharides (SP@COS complex was prepared by combining chitooligosaccharides with Spirulina through electrostatic adsorption. The binding of the complex was characterized by zeta potential, z-average size, and fluorescence labeling. Ultraviolet-visible spectroscopy (UV-Vis) showed the encapsulation efficiency and the drug loading efficiency reached up to 90% and 16%, respectively. The prepared SP@COS2 exhibited a profound synergistic inhibition effect on bacterial and fungal biofilms, which was mainly achieved by destroying the cell structure of the biofilm. These results demonstrate the potential of Spirulina-chitooligosaccharides complex as a biofilm inhibitor and provide a new idea for addressing the harm of pathogenic microorganisms.

Botanicals as a Source of Nanomaterial for Pest and Disease Management

Sustainable food production for a rapidly growing human population is one of the major challenges faced by the agriculture sector globally. Plant pests and pathogens cause significant reductions in crop production, with estimated global losses of 20-40% year-1, resulting in an increased use of environmentally toxic pesticides & fertilizers. The growing numbers of studies in nanotechnology are producing novel applications in many fields of science, especially in plant biotechnology and agriculture. Nanomaterials (NMs) have been used in breakdown of pollutants and reported worldwide for several different environmental applications. They play an important role in agriculture as nano-fertilizers and nano-pesticides, prepared by many methods such as physical, green synthesis or chemical synthesis methods. Green synthesis involves use of biological resources as microorganisms or plant extracts and doesn’t permit the use of any toxic chemicals, hence less bio-hazardous. Rate of reduction of metal ions using phytosynthesis has been observed to be much faster than microbial synthesis. Thus, it is considered as an accessible alternative for large scale production of nanomaterials, without use of chemicals. Phytosynthesized nanomaterials show excellent antibacterial effects, antifungal effects and anti-pest activity. Ocimum sanctum, Azadiracta indica, Paederia foetida, etc. had been successfully reported to be used in synthesis of many NMs of silver, gold, zinc, etc. Botanical nanomaterials offer considerable potential for increasing agricultural productivity and protection while reducing negative impacts on the environment and human health simultaneously.

Preparation, characterization of basil essential oil liposomes unidirectional single-conducting water sustained-release pads and their preservation properties to Lateolabrax japonicus fillets

The juice exudation of aquatic products oozes out during storage can influence storage quality. Herein, a novel basil essential oil liposome unidirectional water-conducting sustained-release preservation pads (BEOL/UCSP) were prepared with nylon mesh as water-conducting layer, basil essential oil liposome (BEOL) as sustained-release preservation layer, and diatomite and absorbent-cotton as water-absorbing layer. EL/UCSP, β-CL/UCSP, and BEO/UCSP were prepared after BEOL was replaced by eugenol liposome, β-caryophyllene liposome, and BEO. BEOL are microspheres with bilayer structure, had good storage stability, centrifugal stability, thermal stability, embedding capacity, sustained-release, and oxidation resistance, and the main components of preservatives had a synergistic effect on antibacterial properties. The pads without preservative can initially slow down quality deterioration. BEOL/UCSP can directionally absorb exudate and realize long-term sustained-release of preservative, has excellent antibacterial and antioxidant effect, and extended shelf life of Lateolabrax japonicus fillets from 6.0 days to 12.8 days. The BEOL/UCSP can provide technical theoretical support for preservation materials.

Gelatinase-responsive biodegradable targeted microneedle patch for abscess wound treatment of S. aureus infection

Abscess wound caused by bacterial infection is usually difficult to heal, thus greatly affect people's quality of life. In this study, a biodegradable drug-loaded microneedle patch (MN) is designed for targeted eradication of S. aureus infection and repair of abscess wound. Firstly, the bacterial responsive composite nanoparticle (Ce6@GNP-Van) with a size of about 182.6 nm is constructed by loading the photosensitizer Ce6 into gelatin nanoparticle (GNP) and coupling vancomycin (Van), which can specifically target S. aureus and effectively shield the phototoxicity of photosensitizer during delivery. When Ce6@GNP-Van is targeted and enriched in the infected regions, the gelatinase secreted by the bacteria can degrade GNP in situ and release Ce6, which can kill the bacteria by generating ROS under laser irradiation. In vivo experiments show that the microneedle is basically degraded in 10 min after inserting into skin, and the abscess wound is completely healed within 13 d after applying Ce6@GNP-Van-loaded MN patch to the abscess wound of the bacterial infected mice with laser irradiation, which can simultaneously achieve the eradication of biofilm and subsequent wound healing cascade activation, showing excellent synergistic antibacterial effect. In conclusion, this work establishes a synergistic treatment strategy to facilitate the repair of chronic abscess wound.

An injectable and thermosensitive hydrogel with nano-aided NIR-II phototherapeutic and chemical effects for periodontal antibacteria and bone regeneration

Periodontitis is a common public health problem worldwide and an inflammatory disease with irregular defect of alveolar bone caused by periodontal pathogens. Both antibacterial therapy and bone regeneration are of great importance in the treatment of periodontitis. In this study, injectable and thermosensitive hydrogels with 3D networks were used as carriers for controlled release of osteo-inductive agent (BMP-2) and Near Infrared Region-II (NIR-II) phototherapy agents (T8IC nano-particles). T8IC nano-particles were prepared by reprecipitation and acted as photosensitizer under 808 nm laser irradiation. Besides, we promoted photodynamic therapy (PDT) through adding H2O2 to facilitate the antibacterial effect instead of increasing the temperature of photothermal therapy (PTT). Hydrogel + T8IC + Laser + BMP-2 + H2O2 incorporated with mild PTT (45 °C), enhanced PDT and sustained release of BMP-2. It was present with excellent bactericidal effect, osteogenic induction and biosafety both in vitro and in vivo. Besides, immunohistochemistry staining and micro-CT analyses had confirmed that PTT and PDT could promote bone regeneration through alleviating inflammation state. Altogether, this novel approach with synergistic antibacterial effect, anti-inflammation and bone regeneration has a great potential for the treatment of periodontitis in the future.

A bio-platform TCN@HKUST-1 with admirable biocompatibility was applied to the antibacterial field

Antibiotics are powerful weapons against bacteria and the unique porous structure makes metal–organic frameworks be good choices for antibiotic delivery. In this work, metal–organic framework HKUST-1 with excellent biocompatibility was synthesized to entrap the antibacterial tetracycline hydrate (TCN) obtaining TCN@HKUST-1 system. The drug loading amount of the system was 54.90 wt%. TCN@HKUST-1 showed excellent antibacterial effects against both Staphylococcus aureus and Escherichia coli due to the antibacterial Cu2+ and TCN, revealing utilizable potentiality in the field of antibacterial application.

Antimicrobial activity enabled by chitosan-ε-polylysine-natamycin and its effect on microbial diversity of tomato scrambled egg paste.

For a long time, food spoilage posed a severe impairment on food safety and public health. Although chemical preservatives are commonly used to inhibit spoilage/ pathogenic microbial growth, the disadvantages of a single target, potential toxicity and high dose of use limit the better use of preservatives. In this research, the combination of natural preservatives: Natamycin (Nat), ε-polylysine (ε-PL), and Chitosan (CS) could achieve an excellent antimicrobial effect including bacteria and fungi, and reduce the usage of a single preservative. Compound preservatives could destroy microbial morphology and damage the integrity of the cell wall/membrane by leakage of protein and alkaline phosphatase (AKP). Besides, high-throughput sequencing revealed that compound preservatives could decrease microbial diversity and richness, especially, Pseudomonas, Acinetobacter, Fusarium, and Aspergillus. Therefore, the combination of 1/8×MIC CS, 1/4×MIC ε-PL, and 1/2×MIC Nat can achieve an excellent antibacterial effect, providing new ideas for food preservation.

Anti-aging and Antimicrobial Effects of the Stems and Roots of Sedum kamtschaticum in Cosmetic Production

Purpose: Sedum kamtschaticum Fisch. (SK), a plant native to Korea, was studied as a natural preservative and antiaging cosmetic ingredient.Methods: The stems and roots of SK were separated; extracted through reflux with 70% ethanol; and fractionated with n-hexane, chloroform, ethyl acetate, n-butyl alcohol, and water. The ethyl acetate fractions were evaluated for their antiaging effects, including antiglycation activity and elastase and collagenase inhibitory activity. Their antimicrobial activity on seven microorganisms was evaluated using the paper disk diffusion method and challenge test. In addition, the stability of lotion formulations and skin penetration were assessed using the Franz diffusion cell method.Results: The ethyl acetate fractions of SK with the best antioxidant effects exhibited better antiglycation and collagenase-inhibitory activity than the positive control as well as excellent antibacterial effects against Escherichia coli and Staphylococcus aureus. Emulsion formulations containing 0.05% and 0.1% SK stem extract exhibited synergistic preservative effects. The SK stem extract displayed the ability to penetrate into an artificial membrane and human cadaver skin.Conclusion: SK extracts can be used as antiaging and antimicrobial cosmetic materials.

Development and Study of Mosquitocidal and Antibacterial Properties of Typhonium trilobatum-Synthesized ZnO NPS and their Impact on the Predation Efficiency of Guppy Poecilia reticulata against the Dengue vector, Aedes aegypti

Dengue fever is an arbovirus spread mostly by Aedes mosquitos. Every year, there is an increase in the incidence of dengue infection and transmission. As a result, the need for an effective measure remains a top concern. The current work aims to assess the effectiveness of Typhonium trilobatum leaf extract synthesized zinc oxide nanoparticles (ZnO NPs) against the Dengue vector, Aedes aegypti. We synthesized zinc nanoparticles by reducing and stabilizing it using T. trilobatum leaf extract. UV-vis spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, field emission scanning electron microscopy, transmission electron microscopy and EDAX analysis were used for analyzing nanoparticles. T. trilobatum leaf extract and biosynthesized ZnONPs were extremely efficient against Ae. aegypti young instars, with LC50 values ranging from 36.633 ppm (larva I) to 102.436 ppm (pupa) and 1.555 ppm (larva I) to 6.906 ppm (pupa). The predation effectiveness of Poecillia reticulata guppy fish against A. aegypti I - IV instar larvae were 49.8 and 25.9 %, respectively. Predation was 78.3 and 39.8 % in ZnO-contaminated environments, respectively. The results of T. trilobatum leaf extract synthesized ZnONPs showed considerable larvicidal action with an increase in predatory potential of the guppy fish P. reticulata. To screen the antibacterial activities of T. trilobatum leaf extract and Biosynthesized ZnO NPs against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi, the agar disk diffusion and minimum inhibitory concentration procedures were used. The biosynthesized ZnO NPs showed excellent antibacterial effects against bacterial pathogens. Overall, our study suggests that T. trilobatum leaf extract synthesized ZnO NPs could be used in mosquito control as well as the creation of novel chemotherapeutic medicines with low systemic toxicity.

An Efficient Antimicrobial Performance of Hybrid Functionalized MWCNTs/GNPts Bionanocomposites Based on Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)

AbstractHaloferax mediterranei archaea has been utilized to biosynthesize Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) polyester from date waste as carbon source. The produced biopolymer has been composited with different percentages (1 %, 3 %, 5 % and 10 %) of a hybrid filler based on 1 : 1 carboxylated multi‐walled carbon nanotubes (CMWCNTs) and graphene nanoplates (GNPts). The synthesized bionanocomposites PHBV/(CMWCNTs‐GNPts)(1,3,5,10%) have been characterized by FTIR, TGA, XRD, SEM and EDX. In addition, they were studied for their antibacterial properties against gram negative and gram positive strains of M. Luteus, S. Aureus, P. Aerugensa and E. Coli, and the results showed excellent antibacterial effect especially against gram negative strains of P. Aerugensa and E. Coli, showing inhibition zones of 52 % and 81 %, respectively, compared to chloramphenicol control that is used. Also, antifungal activities were investigated against G. Candidum and C. Albicans and showed that the produced bionanocomposites had inhibition zones of 32 % and 73 %, respectively, compared to the antifungal drug clotrimazole which was used as control.

Effects of structural changes on antibacterial activity and cytotoxicity due to proline substitutions in chimeric peptide HnMc

Owing to the rapidly increasing emergence of multidrug-resistant pathogens, antimicrobial peptides (AMPs) are being explored as next-generation antibiotics. However, AMPs present in nature are highly toxic and exhibit low antibacterial activity. Simple modifications, such as amino acid substitution, can enhance antimicrobial activity and cell selectivity. Herein, we show that HnMc-W, substituted by the Phe1Trp analog of HnMc, a chimeric peptide, resulted in membranolytic antibacterial action and enhanced salt tolerance, whereas HnMc-WP1 with one Ser9Pro substitution resulted in a proline-kink helical structure that increased salt-tolerant antibacterial effects and reduced cytotoxicity. In addition, the HnMc-WP2 peptide, designed with a PXXP motif, had a flexible central hinge in its α-helical structure due to the introduction of two Pro and two Gln (X positions, by deletion of two Gln at positions 16 and 17) residues instead of Ser at position. HnMc-WP2 exhibited excellent antibacterial effects without cytotoxicity in vitro. Moreover, its potent antibacterial activity was demonstrated in a drug-resistant Pseudomonas aeruginosa-infected mouse model in vivo. Our findings provide valuable information for the design of peptides with high antibacterial activity and cell selectivity.

Dimethylaminododecyl Methacrylate-Incorporated Dental Materials Could Be the First Line of Defense against Helicobacter pylori.

Oral cavity is an essential reservoir for H. pylori. We aimed to investigate the antibacterial effects of dimethylaminododecyl methacrylate (DMADDM) against H. pylori. Modified giomers were prepared by introducing 0%, 1.25% and 2.5% DMADDM monomers. Broth microdilution assay, spot assay, Alamer Blue assay, PMA-qPCR, crystal violet staining, scanning electron microscopy observation and live/dead bacterial staining were performed to evaluate the antibacterial and antibiofilm effects of DMADDM and modified giomers in vitro. Urease assay, qPCR, hematoxylin-eosin staining and ELISA were performed to evaluate the inflammation levels and colonization of H. pylori in vivo. In vitro experiments indicated that the minimum inhibitory concentration and minimum bactericidal concentration of DMADDM were 6.25 μg/mL and 25 μg/mL, respectively. It inhibited H. pylori in a dose- and time-dependent manner, and significantly reduced the expression of cagA, vacA, flaA and ureB. DMADDM-modified giomers inhibited the formation of H. pylori biofilm and reduced live cells within it. In vivo experiments confirmed that the pretreatment with DMADDM-modified dental resin effectively reduced the gastric colonization of oral-derived H. pylori, suppressed systemic and local gastric inflammation. DMADDM monomers and DMADDM-modified giomers possessed excellent antibacterial and antibiofilm effects on H. pylori. Pretreatment with DMADDM-modified giomers significantly inhibited the gastric infection by H. pylori.

A comparative study on antibacterial activity of sulfur- and phosphorus- doped carbon quantum dots

Effectively killing microbial pathogens without inducing resistance is a challenge, especially in the treatment of infectious diseases. In this study, sulfur (S)- and phosphorus (P)-doped carbon quantum dots (CQDs) were synthesized by one-step hydrothermal method using m-aminophenol as carbon source, thiourea and phosphoric acid as S and P dopants, respectively. Compared with S-CQDs, P doping could lead to a red-shift of the maximum emission wavelength. In addition, the as-prepared S-CQDs and S, P-CQDs exhibited unique antibacterial efficacy against both E. coli and S. aureus without developing drug resistance. In contrast, the S, P-CQDs had no preference for Gram-positive and Gram-negative bacteria, and they had a somewhat reduced bactericidal efficacy than that of S-CQDs, but S, P-CQDs had better bacteriostatic stability than S-CQDs. Such an excellent antibacterial effect might be attributed to the generation of a large number of intracellular reactive oxygen species (ROS), which disrupted the structure and the regular surface of bacterial cell. Consequently, the prepared S-CQDs and S, P-CQDs could be applied as antibacterial drugs with broad-spectrum antibacterial activity and without drug resistance.

Single- and Multilayer Build-Up of an Antibacterial Temperature- and UV-Curing Sol-Gel System with Atmospheric Pressure Plasma.

The versatility of sol-gel systems makes them ideal for functional coatings in industry. However, existing coatings are either too thin or take too long to cure. To address these issues, this paper proposes using an atmospheric pressure plasma source to fully cure and functionalize thicker sol-gel coatings in a single step. The study explores coating various substrates with sol-gel layers to make them scratch-resistant, antibacterial, and antiadhesive. Microparticles like copper, zinc, or copper flakes are added to achieve antibacterial effects. The sol-gel system can be sprayed on and quickly functionalized on the substrate. The study focuses on introducing and anchoring particles in the sol-gel layer to achieve an excellent antibacterial effect by changing the penetration depth. Overall, this method offers a more efficient and effective approach to sol-gel coatings for industrial applications. In order to achieve a layer thickness of more than 100 µm, the second part of the study proposes a multilayer system comprising 15 to 30 µm thick monolayers that can be modified by introducing fillers (such as TiO2) or scratch-resistant chemicals like titanium isopropoxide. This system also allows for individual plasma functionalization of each sol-gel layer. For instance, the top layer can be introduced with antibacterial particles, while another layer can be enhanced with fillers to increase wear resistance. The study reveals the varying antibacterial effects of spherical particles versus flat flakes and the different scratch hardnesses induced by changes in pH, number of layers, and particle introduction.

A self-reported inhibitor of metallo-carbapenemases for reversing carbapenem resistance

Metallo-carbapenemases-mediated carbapenem-resistant Enterobacterales (CREs) has been acknowledged as “urgent threat” by the World Health Organization. The discovery of new strategies that block metallo-carbapenemases activity to reverse carbapenem resistance is an urgent need. In this study, a coumarin copper complex containing a PEG linker and glucose ligand, GluC-Cu, was used to reverse carbapenem resistance. Interestingly, it could effectively inhibit metallo-carbapenemases (NDM-1, IMP-1 and ImiS) with an IC50 value in the range of 0.23–1.21 μM, and simultaneously release the green fluorescence signal (GluC), therefore exhibiting self-reported inhibition performance. The inhibition mechanism of oxidizing Zn(II) thiolate site of NDM-1 from Cu2+ to Cu+ was verified by fluorescence assay, HR-MS, and XPS. Moreover, GluC-Cu in combination with meropenem showed excellent synergistic antibacterial effect to effectively combat E. coli expressing metallo-carbapenemases in vitro and in a mice infection model. This bifunctional metallo-carbapenemases inhibitor provides a novel chemical tool to overcome carbapenem resistance.