Outstanding Antibacterial Properties Research Articles

Design of a novel CoCrFeNiCu0.3 high entropy alloy with desirable mechanical, corrosion and anti-bacterial properties via adjusting Cu distribution

Cu-containing high-entropy alloys (HEAs) with good antibacterial properties have application potential in the field of marine engineering. However, Cu tends to segregate in HEAs, which deteriorates the mechanical properties and corrosion resistance. This work proposed a feasible strategy to eliminate Cu segregation in FCC-structured HEAs by ball milling and spark plasma sintering using HEA powders and Cu powders. It was found that, with the increase of sintering temperature, the Cu-rich phase gradually dissolved-into the CoCrFeNiCu0.3 HEA and finally disappeared. Meanwhile, the distribution of Cu elements in HEAs gradually became uniformed. CoCrFeNiCu0.3 HEA with uniform distribution of Cu was successfully fabricated by sintering at 1400 °C. The dissolution of Cu-rich phase synergistically improved the strength and plasticity of CoCrFeNiCu0.3 HEAs. Meanwhile, the galvanic corrosion caused by Cu-rich phases was effectively restrained by the uniform distribution of Cu. Furthermore, the sintered CoCrFeNiCu0.3 HEAs preserved good antibacterial properties with an antibacterial rate above 95% due to the combined action of toxic sterilization of Cu ions and contact sterilization of Cu atoms. The CoCrFeNiCu0.3 HEAs with uniform distribution of Cu not only displayed good mechanical properties and corrosion resistance, but also exhibited outstanding antibacterial properties. This work provided a design concept for the development of marine structural materials.

Doping silver nanoparticles into reverse osmosis membranes for antibacterial properties

Abstract Polyamide composite reverse osmosis (RO) membranes occupy an important position in water treatment. However, membrane fouling, especially biofouling, can lead to a significant decrease in membrane permeability. Therefore, reducing biological contamination is a significant and important property of an RO membrane. In this article, a hypothesis on the development of a new kind of RO membrane for antibacterial purposes was prepared by the modification of gallic acid (GA) and silver nanoparticles (AgNPs). Then, experiments were carried out to verify the hypothesis, getting a modified RO membrane with the composite of GA@AgNPs. The water flux of the GA@AgNPs RO membrane was 31.1 L·m−2·h−1, which was 46.7% higher than that of the original membrane, while the rejection rate of salt remained at 93.8–97.6%. Moreover, the GA@AgNPs RO membranes exhibited outstanding antibacterial properties with more than 99.9% antibacterial efficiency against both Escherichia coli and Staphylococcus aureus. Our work provides a new idea for solving the problem of biofouling RO membranes.

Mussel-inspired self-assembly platform for staged implant osseointegration: Combining early anti-infection and late osteoinduction

Current implant systems still lack the ability to combat implant-associated infections (IAI) and insufficient osseointegration to reduce the risk of implant failure. There’s an urgent need to develop an effective implant modification method to match the needs of different biological stages post-implantation, which requires anti-infection at the initial stage and osseointegration at the latter long-term stage. Here, we constructed a mussel-inspired layer-by-layer (LbL) self-assembly implant modification platform via tannic acid (TA), sequentially anchoring osteoanabolic drug (Abaloparatide, ABL) and antibacterial (Dimethylaminohexadecyl methacrylate, DMAHDM) to the Titanium (Ti) surface (Ti/ABL/DMAHDM). The Ti/ABL/DMAHDM exhibited outstanding antibacterial properties at the initial stage with an antibacterial rate of 100 % both in vitro (24 h) and in vivo (48 h). Moreover, it showed significant osteogenic induction ability at the latter long-term stage both in vitro (7 days and 14 days) and in vivo (4 weeks), accompanied by good biocompatibility. This TA-mediated self-assembly modification implants platform with staged regulation of anti-infection and osteoinduction offers potential clinical prospects for improving osseointegration after implantation.

Passion fruit peel pectin/chitosan based antibacterial films incorporated with biosynthesized silver nanoparticles for wound healing application

Antimicrobial pectin/chitosan composite films have potential as wound dressing and food packaging. However, almost biofilms were synthesized through chemical routes, causing eco-unfriendliness, and negative impacts on the environment and human health. Green synthesis of composite films incorporating with biosynthesized AgNPs is therefore necessary to enhance mechanical and antimicrobial activities. This study focused on the influence of biosynthesized AgNPs on characteristics of passion fruit peel pectin/chitosan (P/CH) biofilms. Characterization, mechanical, antimicrobial activities of P/CH/AgNPs biofilms were evaluated. Incorporating AgNPs into P/CH-based films significantly exerted apparent color and optical properties of biofilms. As AgNPs concentration increased, P/CH/AgNPs biofilms had higher water content (20.1%), better water vapor permeability (1.28 × 10–9 g/mm h Pa), but lower mechanical, water solubility (43.98%), swelling (630.29 ± 11.79%) indexes. P/CH/AgNPs biofilms exhibited outstanding antibacterial properties against S. aureus, B. cereus, P. aeruginosa, K. pneumonia. As expected, in vivo results consolidated the evidence of excellent wound closure (100%) of P/CH/AgNPs biofilms after 15 days. Our findings recommend P/CH/AgNPs antibacterial biofilms have promising biomedical applications.

Advanced Hydrogels Combined with Silver and Gold Nanoparticles against Antimicrobial Resistance.

The development of multidrug-resistant (MDR) microorganisms has increased dramatically in the last decade as a natural consequence of the misuse and overuse of antimicrobials. The World Health Organization (WHO) recognizes that this is one of the top ten global public health threats facing humanity today, demanding urgent multisectoral action. The UK government foresees that bacterial antimicrobial resistance (AMR) could kill 10 million people per year by 2050 worldwide. In this sense, metallic nanoparticles (NPs) have emerged as promising alternatives due to their outstanding antibacterial and antibiofilm properties. The efficient delivery of the NPs is also a matter of concern, and recent studies have demonstrated that hydrogels present an excellent ability to perform this task. The porous hydrogel structure with a high-water retention capability is a convenient host for the incorporation of the metallic nanoparticles, providing an efficient path to deliver the NPs properly reducing bacterial infections caused by MDR pathogenic microorganisms. This article reviews the most recent investigations on the characteristics, applications, advantages, and limitations of hydrogels combined with metallic NPs for treating MDR bacteria. The mechanisms of action and the antibiofilm activity of the NPs incorporated into hydrogels are also described. Finally, this contribution intends to fill some gaps in nanomedicine and serve as a guide for the development of advanced medical products.

Calcium Phosphate Bone Cements Incorporated with Black Phosphorus Nanosheets Enhanced Osteogenesis.

For decades, calcium phosphate bone cements (CPCs) showed impressive advantages for their good biocompatibility, injectability, and osteoconductivity in the bone repair field. However, it is still difficult to prepare CPCs with outstanding antibacterial and self-curing properties, sufficient phosphorus release, and osteoinductivity for clinical application. Herein, we used partially crystallized calcium phosphate and dicalcium phosphate anhydrate particles incorporated with black phosphorous nanosheets to prepare calcium phosphate bone cements (CPCs). The curing time, compressive strength, photothermal properties, and degradation performance of BP/CPC were investigated. In addition, the cytocompatibility and osteoinductivity of BP/CPC were evaluated by cell adhesion, cytotoxicity, alkaline phosphatase detection, alizarin red staining, and western blot assay. The results indicated that BP/CPC showed adjustable curing time, good cytocompatibility, outstanding photothermal properties, and osteoinductivity, suggesting their potential application for bone regeneration.

Designing double-site lipidated peptide amphiphiles as potent antimicrobial biomaterials to combat multidrug-resistant bacteria.

Rapidly evolving antimicrobial resistance and extremely slow development of new antibiotics have resulted in multidrug-resistant bacterial infections that present a serious threat to human health. Antimicrobial peptides (AMPs) provide promising substitutes, but more research is needed to address several of their present limitations, such as insufficient antimicrobial potency, high toxicity, and low stability. Here, we designed a series of novel double-site lipidated peptide amphiphiles based on a heptad repeat parent pentadecapeptide. The double-site lipidated peptide amphiphiles showed a broad spectrum of antimicrobial activities. Especially the double-site lipidated peptide amphiphile WL-C6 exhibited high potency to inhibit multidrug-resistant bacteria without significant toxicity toward mammalian cells. Furthermore, even at physiological salt ion concentrations, WL-C6 still exhibited outstanding antibacterial properties, and a sizeable fraction of it maintained its molecular integrity after being incubated with different proteases. Additionally, we captured the entire process of WL-C6 killing bacteria and showed that the rapid bacterial membrane disruption is the reason of bacterial death. Overall, WL-C6 shows great promise as a substitute for conventional antibiotics to combat the growing threat of multidrug-resistant bacterial infections.

Dislocation-rich BiOI nanosheets designed by nitrogen ion implantation for improving NIR-triggered bactericidal activity

Designing high-performance antibacterial agents is crucial for efficient bacterial inactivation in environmental applications. In this study, a potential photothermocatalytic bactericidal candidate BiOI nanosheets with dislocation-rich defects are rationally constructed by employing high-energy nitrogen ion implantation engineering. The constructed BiOI produces an enhanced conductivity due to the lattice atom replacement induced by nitrogen ion implantation, which favors the separation and transfer of electron-hole and inhibits backflow of electrons, leading to boosted photocatalytic activity. Meanwhile, the photothermal activity is dramatically enhanced by controlling the ion irradiation fluence-induced dislocation density. Outstanding antibacterial properties are demonstrated by the long-term irreversible photothermal and photocatalytic destruction under near infrared (NIR) illumination. The ample theory and experiments reveal that the ion-beam implantation is a reliable technique to engineer nanomaterial photothermal catalysts, and the irradiated BiOI nanosheets are highly effective in prompting the bactericidal process.

Building rapid water transport channels within thin-film nanocomposite membranes based on 2D mesoporous nanosheets

The fabrication of novel thin-film nanocomposite (TFN) membranes with superior flux, rejection as well as prolonged stability is being requested by membrane industries for saving energy and cost. In this regard, in the present research work we developed novel TFN membranes using amine-rich synthetic talc (NHST) nanosheets within diethylenetriamine (DETA) and trimesoyl chloride (TMC) monomers over a polydopamine (PDA) coating layer. Different concentrations (0.2–1 %) of NHST nanosheets are applied for the fabrication of TFN membranes and comparatively examined with a thin-film composite (TFC) membrane. In-situ synthesized NHST nanosheet phases are confirmed by several characterization techniques and results are explored in depth. All prepared membranes are well investigated to confirm the incorporation of NHST by several characterization techniques, like FE-SEM, ATR-FTIR, HR-TEM, XPS, PXRD, TGA, and contact angle. It is found that a small amount of NHST doping in the TFN layer considerably improved the performance in the form of permeability and rejection. The developed TFN membranes showed hydrophilic characteristics as confirmed by the contact angle. Water flux performance of TFN membranes was also observed comparatively higher than TFC membranes. Optimized NHST-PDT-TFN2 membrane with NHST concentration 0.5 % resulted in 98.96, 95.35, 93.83 and 21.66 % rejection for Na2SO4, MgSO4, CuSO4 and NaCl salts, respectively together with permeance up to 24.45, 22.72, 26.45 and 30.75 Lm−2h−1b−1. The present research finding concludes that the incorporation of a little quantity of NHST nanosheets in the TFN layer plays a unique potential role in the enhancement of flux and rejection of targeted mineral salts. Additionally, the NHST-PDT-TFN membranes revealed outstanding antibacterial properties signifying that contact with microorganisms does not affect the performance and sustains the fouling resistance. The antifouling study of the membranes concluded that the addition of nanomaterials has led to enhanced antifouling tendency and low irreversible fouling, improving the longevity of the membranes.

Mussel-inspired adhesive zwitterionic composite hydrogel with antioxidant and antibacterial properties for wound healing

The skin can be easily injured and attacked by external pathogens, leading to wound infection and wound healing delay. Traditional dressings adhere to wounds only and can cause secondary damage to the new epithelium and bleeding. Herein, a highly adhesive zwitterionic composite hydrogel wound dressing (PDA/PSBMA/NFC/Zn2+ [PSNZn]) with outstanding antibacterial properties, good biocompatibility and excellent rheological properties was prepared by introducing zinc ion-loaded polydopamine (PDA)-coated nanofibrillated cellulose into a covalently-crosslinked sulfobetaine methacrylate (SBMA) network. In vitro and in vivo experiments showed the broad-spectrum and lasting antibacterial activity of the PSNZn composite hydrogel against Escherichia coli and Staphylococcus aureus. In summary, the PSNZn composite hydrogel is an excellent wound dressing candidate with efficient antibacterial properties, high adhesion, excellent biocompatibility and good rheological properties.

Fabrication and characterization of polymer nanocomposites membrane (Cu-MOF@CA/PES) for water treatment

In present work, the hydrophilic Cu-MOF was synthesized by solvothermal method and incorporated with a cellulose acetate (CA)/polyether sulfone (PES) polymer membrane casting solution using a phase inversion approach to create new mixed matrix membranes of nanocomposite membrane material (Cu-MOF@CA-PES). The physical and chemical characteristics of the prepared materials were examined using different analytical techniques such as, FT-IR, XRD, TGA, XPS, SEM, TEM, AFM, BET and contact angle analysis. The membrane performance was analyzed using pure water flux (PWF), Bovine sirup albumin (BSA) and Humic acid (HA) rejection. The maximum water flux was 28.5 L m−2 h−1 with an 85 % BSA rejection rate and a 79 % HA rejection rate respectively and the contact angle value reduced from 75.27° to 46.02° respectively confirming that the modified membrane material is hydrophilic nature. The presence of Cu-MOF membrane material also exhibited outstanding anti-bacterial properties against pseudomonas aeruginosa, E. coli, Enterococcus faecalis and Staphylococcus aureus for gram positive and gram negative.

Emerging starch composite nanofibrous films for food packaging: Facile construction, hydrophobic property, and antibacterial activity enhancement

Polymers synthesized from green resources have many advantages in food packaging and hence their development is very important. Herein, starch/polyvinyl alcohol (PVA) nanofibrous composite films were fabricated by electrospinning technology. Steam-induced cross-linking reaction with glutaraldehyde (GTA) and silver sodium zirconium phosphate (Ag-ZrP) was employed to improve the hydrophobic and antibacterial properties of the constructed nanofibrous films, respectively. The effects of starch/PVA ratio on the micro-morphology and mechanical properties of the binary composite film were investigated. The composite film showed optimal uniformity, bead-free electrospun nanofibers, with enhanced mechanical strength for the 60/40 (v/v) starch/PVA composite. Moreover, the crystallinity of PVA was reduced during the electrospinning process, whereas the introduction of PVA strengthened the hydrogen interactions and improved the thermal stability of the composite films. After the cross-linking with GTA, the starch/PVA films became more hydrophobic. Furthermore, the starch/PVA films embedded with Ag-ZrP had outstanding antibacterial property against both Gram-negative and Gram-positive bacteria. This work demonstrated the potential prospects of electrospun starch nanofibrous films in the food packaging field.

High strength and toughness transparent waterborne polyurethane with antibacterial performance

To reach a more sustainable society, it is an irresistible trend to replace the solvent-based polyurethane with waterborne polyurethane (WPU). However, it remains a challenge to fabricate WPU materials with excellent mechanical properties. Herein, a transparent WPU with strength of 30.1 MPa and toughness of 195.7 MJ/m3 is developed by incorporating hydantoin diol (HD) into WPU macromolecule. The polar segments of WPU interact with each other by H-bonds and agglomerate together to form hard phase, which disperse in soft polycaprolactone diol (PCL) phase, forming micro-phase separated domains. It significantly enhances the tensile strength and toughness of the WPU. In comparison with covalent bonds, the reversibility of dynamic physical interactions of H-bonds enables the materials to be healed by heating. In addition, the 3 h-healed HDPU2 film exhibits high toughness (166.9 MJ/m3), tensile strength (20.6 MPa) and strain (2195 %). Furthermore, the HDPU2 film presents outstanding antibacterial properties after chlorination, inactivating 100 % of S. aureus and 96.2 % of E. coli within 60 min.

Structural, Morphological, Optical, and Antibacterial Activities of Zinc Oxide Nanopowders: A Comparative Study of Green and Soft Chemical Synthesis

Zinc oxide, a well-known inorganic metal oxide in nanoparticle form, has outstanding antibacterial properties. In this work, the authors focus on determining ZnO nanoparticles’ structural, optical, and antibacterial activity. A simple soft chemical route synthesizes C-ZnO nanoparticles chemically, while the green synthesis method is used to prepare G-ZnO nanoparticles. Ocimum tenuiflorum leaf extract was used to prepare G-ZnO nanopowders. These samples are investigated and compared in terms of their structural, morphological, optical, and antibacterial properties. According to XRD investigations, the synthesized ZnO nanopowders possess a hexagonal structure. The particle size of G-ZnO is smaller than that of C-ZnO nanoparticles. The XPS result revealed the binding and interactions between molecules. The FTIR study confirmed the presence of molecules and their vibrations. UV-vis-DRS spectroscopy was used to investigate optical properties such as reflectance and band gap. The grain size of the G-ZnO nanopowders was decreased, and oxygen vacancy was produced. The antibacterial efficiency of plant extracts against two different bacterial strains, S. aureus (Gram-positive) and E.coli (Gram-negative), has been studied and reported.

A review of silver‐dopped graphene oxide nanocomposite: Synthesis and multifunctional applications

AbstractIn recent years, the applications of nanomaterials are getting more common in commercial products. Amongst them, silver nanoparticles (AgNPs) are the most well‐known nanomaterials for their outstanding antibacterial properties and potential applications in the biomedical field. The agglomeration of AgNPs due to their high surface energy has diminished the actual antibacterial applications of these plasmonic nanoparticles. To tackle this problem, the AgNPs are grafted onto graphene oxide (GO) sheets (Ag/GO) to minimize the agglomeration of AgNPs and enhance the extraordinary antibacterial characteristics of AgNPs thanks to several outstanding features of GO. Ag/GO composite also exhibits other properties such as good optical sensitivity to trace heavy metal ions, adsorption affinity, and catalytic activity for the removal of organic compounds. With all the possibilities, Ag/GO can be considered a multifunctional nanocomposite that can be applied in various fields such as biomedical treatment and environmental remedy.

Antibacterial, Antibiofilm, and Antiviral Farnesol-Containing Nanoparticles Prevent Staphylococcus aureus from Drug Resistance Development.

Multidrug antimicrobial resistance is a constantly growing health care issue associated with increased mortality and morbidity, and huge financial burden. Bacteria frequently form biofilm communities responsible for numerous persistent infections resistant to conventional antibiotics. Herein, novel nanoparticles (NPs) loaded with the natural bactericide farnesol (FSL NPs) are generated using high-intensity ultrasound. The nanoformulation of farnesol improved its antibacterial properties and demonstrated complete eradication of Staphylococcus aureus within less than 3 h, without inducing resistance development, and was able to 100% inhibit the establishment of a drug-resistant S. aureus biofilm. These antibiotic-free nano-antimicrobials also reduced the mature biofilm at a very low concentration of the active agent. In addition to the outstanding antibacterial properties, the engineered nano-entities demonstrated strong antiviral properties and inhibited the spike proteins of SARS-CoV-2 by up to 83%. The novel FSL NPs did not cause skin tissue irritation and did not induce the secretion of anti-inflammatory cytokines in a 3D skin tissue model. These results support the potential of these bio-based nano-actives to replace the existing antibiotics and they may be used for the development of topical pharmaceutic products for controlling microbial skin infections, without inducing resistance development.

Functionalized Ti3C2Tx-based nanocomposite coatings for anticorrosion and antifouling applications

Marine corrosion and biofouling are a major issue affecting the development of the marine industry. Traditional single-function coatings, such as those that provide either antifouling or anticorrosion, cannot meet the requirements in the current hostile conditions. In our study, block copolymer-functionalized Ti3C2Tx was successful prepared and employed to synthesize a nanocomposite coating with satisfactory antifouling and anticorrosion performances, in which the anticorrosion agent poly(2-mercaptobenzothiazole) (PMBTMA) was first grafted on the Ti3C2Tx surface, after which the antifouling agent poly(3-sulfopropyl methacrylate potassium (PSPMA) was grafted via surface-initiated atom transfer radical polymerization (SI-ATRP), to obtain the block copolymer (PMBTMA-co-PSPMA)-functionalized Ti3C2Tx (abbreviated as TMS). An appropriate corrosion protection and antifouling mechanism in the functionalized Ti3C2Tx-based epoxy nanohybrid coatings is proposed. It is noteworthy that the antibacterial activity of the proposed coating stems from the synergistic bactericidal effect of Ti3C2Tx and 2-mercaptobenzothiazole (MBT). The outstanding antibacterial properties of the TMS and the strong surface hydration of the anionic polymer brushes PSPMA, endow the as-prepared TMS-based nanocomposite coating (TMS/EP) with good antifouling performance (removal of more than 55% of bacteria and removal rate of microalgae up to 71%). More importantly, the TMS/EP has excellent corrosion resistance ability, which is due to the good synergistic anticorrosion barrier effect of Ti3C2Tx nanosheets and the on-demand release of corrosion inhibitor MBT during the corrosion process.

Engineering DNA-Guided Hydroxyapatite Bulk Materials with High Stiffness and Outstanding Antimicrobial Ability for Dental Inlay Applications.

Programmable base pair interactions at the nanoscale make DNA an attractive scaffold for forming hydroxyapatite (HAP) nanostructures. However, engineering macroscale HAP mineralization guided by DNA molecules remains challenging. To overcome this issue, a facile strategy is developed for the fabrication of ultrastiff DNA-HAP bulk composites. The electrostatic complexation of DNA and a surfactant with a quaternary ammonium salt group enables the formation of long-range ordered scaffolds using electrospinning. The growth of 1D and 2D HAP minerals is thus realized by this DNA template at a macroscale. Remarkably, the as-prepared DNA-HAP composites exhibit an ultrahigh Young's modulus of ≈25GPa, which is comparable to natural HAP and superior to most artificial mineralized composites. Furthermore, anew type of dental inlay with outstanding antibacterial properties is developed using the stiff DNA-HAP. The encapsulated quaternary ammonium group within the dense HAP endows the composite with long-lasting and local antibacterial activity. Therefore, this new type of super-stiff biomaterial holds great potential for oral prosthetic applications.

Controllable oxygen vacancies and morphology engineering: Ultra-high HER/OER activity under base–acid conditions and outstanding antibacterial properties

Introducing vacancy defects and unique morphology is an effective strategy to improve the catalytic performance of transition metal compounds. However, precisely controlling the amount of vacancy defects remains challenging. Here, we propose a facile and efficient hydrothermal accompanying an annealing method to synthesize a series of Mn-doped CoO nanomaterials with controllable oxygen vacancies and unique morphology. The oxygen vacancies amount can be precisely controlled by adjusting the Mn-doping content and is positively correlated with catalytic performance. It was found that the oxygen vacancies amount can reach up to 38.2% over the Mn-doped CoO nanomaterials, resulting in ultra-high hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalytic activity (HER: 25.6 and 37 mV at 10 mA cm−2; OER: 301 and 322 mV at 50 mA cm−2) under both basic and acidic conditions, while reaching 10 mA cm−2 for an ultra-low cell voltage of only 1.52 V, which exceeds that of Pt/C/RuO2 and all reported non-noble metal oxide catalysts. The DFT calculations reveal oxygen vacancies can optimize H* and HOO* intermediates adsorption free energy, thus improving the HER and OER performance. Interestingly, the Mn-doped CoO with rich oxygen vacancies exhibits excellent antibacterial properties in vitro of biomedicine. This work provides new ideas and methods for the rational design and precise control of vacancy defects in transition metal compounds and explores their potential application value in electrochemical water splitting and biomedical fields.

Wooden composite separators with ultrahigh uranium/vanadium selectivity and antibacterial property for capturing uranium from seawater

Herein, wooden composite separators with Fe3+/salicylaldoxime coatings have achieved selective extraction of uranium from seawater. The aldoxime groups inside the salicylaldoxime have been proved with excellent uranium/vanadium selectivity that the adsorption capacity ratios of uranium/vanadium are as high as 9. Moreover, the coatings could also enable the wooden separators with outstanding antibacterial properties owing to the phenolic hydroxyl groups of salicylaldoxime, making it possible for the separators to survive well in complex marine environments. The wooden separators could be further applied for practical dynamic adsorption with much lower mass resistances than typical fiber/power-based adsorbents, benefitting from the vertically aligned channels and high porosities.