Antimicrobial Zinc Research Articles

Antimicrobial zinc oxide/polymer nanocomposites for the removal of toxic textile dye

Antimicrobial zinc oxide/polymer nanocomposites for the removal of toxic textile dye

Injective Programmable Proanthocyanidin-Coordinated Zinc-Based Composite Hydrogel for Infected Bone Repair.

Effectively integrating infection control and osteogenesis to promote infected bone repair is challenging. Herein, injective programmable proanthocyanidin (PC)-coordinated zinc-based composite hydrogels (ipPZCHs) are developed by compositing antimicrobial and antioxidant PC-coordinated zinc oxide (ZnO) microspheres with thioether-grafted sodium alginate (TSA), followed by calcium chloride (CaCl2 ) crosslinking. Responsive to the high endogenous reactive oxygen species (ROS) microenvironment in infected bone defects, the hydrophilicity of TSA can be significantly improved, to trigger the disintegration of ipPZCHs and the fast release of PC-coordinated ZnOs. This together with the easily dissociable PC-Zn2+ coordination induced fast release of antimicrobial zinc (Zn2+ ) with/without silver (Ag+ ) ions from PC-coordinated ZnOs (for Zn2+ , > 100 times that of pure ZnO) guarantees the strong antimicrobial activity of ipPZCHs. The exogenous ROS generated by ZnO and silver nanoparticles during the antimicrobial process further speeds up the disintegration of ipPZCHs, augmenting the antimicrobial efficacy. At the same time, ROS-responsive degradation/disintegration of ipPZCHs vacates space for bone ingrowth. The concurrently released strong antioxidant PC scavenges excess ROS thus enhances the immunomodulatory (in promoting the anti-inflammatory phenotype (M2) polarization of macrophages) and osteoinductive properties of Zn2+ , thus the infected bone repair is effectively promoted via the aforementioned programmable and self-adaptive processes.

Highly efficient and durable antimicrobial nanocomposite textiles

Healthcare associated infections cause millions of hospitalizations and cost billions of dollars every year. A potential solution to address this problem is to develop antimicrobial textile for healthcare fabrics (hospital bedding, gowns, lab coats, etc.). Metal nanoparticle-coated textile has been proven to possess antimicrobial properties but have not been adopted by healthcare facilities due to risks of leaching and subsequent loss of function, toxicity, and environmental pollution. This work presents the development and testing of antimicrobial zinc nanocomposite textiles, fabricated using a novel Crescoating process. In this process, zinc nanoparticles are grown in situ within the bulk of different natural and synthetic fabrics to form safe and durable nanocomposites. The zinc nanocomposite textiles show unprecedented microbial reduction of 99.99% (4 log10) to 99.9999% (6 log10) within 24 h on the most common Gram-positive and Gram-negative bacteria, and fungal pathogens. Furthermore, the antimicrobial activity remains intact even after 100 laundry cycles, demonstrating the high longevity and durability of the textile. Independent dermatological evaluation confirmed that the novel textile is non-irritating and hypoallergenic.

Manufacturing of Zinc Oxide Nanoparticle (ZnO NP)-Loaded Polyvinyl Alcohol (PVA) Nanostructured Mats Using Ginger Extract for Tissue Engineering Applications

In this research, as an alternative to chemical and physical methods, environmentally and cost-effective antimicrobial zinc oxide nanoparticles (ZnO NP) were produced by the green synthesis method. The current study focuses on the production of ZnO NP starting from adequate precursor and Zingiber officinale aqueous root extracts (ginger). The produced ZnO NP was loaded into electrospun nanofibers at different concentrations for various tissue engineering applications such as wound dressings. The produced ZnO NPs and ZnO NP-loaded nanofibers were examined by Scanning Electron Microscopy (SEM) for morphological assessments and Fourier-transform infrared spectrum (FT-IR) for chemical assessments. The disc diffusion method was used to test the antimicrobial activity of ZnO NP and ZnO NP-loaded nanofibers against three representatives strains, Escherichia coli (Gram-negative bacteria), Staphylococcus aureus (Gram-positive bacteria), and Candida albicans (fungi) microorganisms. The strength and stretching of the produced fibers were assessed using tensile tests. Since water absorption and weight loss behaviors are very important in tissue engineering applications, swelling and degradation analyses were applied to the produced nanofibers. Finally, the MTT test was applied to analyze biocompatibility. According to the findings, ZnO NP-loaded nanofibers were successfully synthesized using a green precipitation approach and can be employed in tissue engineering applications such as wound dressing.

Probing Nanoscale Interactions of Antimicrobial Zinc Oxide Quantum Dots on Bacterial and Fungal Cell Surfaces (Adv. Mater. Interfaces 3/2022)

Antimicrobial Zinc Oxide Quantum Dots In article number 2101484, Sheeana Gangadoo, Enrico Della Gaspera, James Chapman, Vi Khanh Truong, and co-workers report that utilizing 5 nm zinc oxide quantum dots (ZnO QDs) result in rapid and high antimicrobial performance against methicillin-resistant Staphylococcus aureus and highly pathogenic yeast Candida auris cells. ZnO QDs are shown to adhere and cluster around microbial cell surfaces, resulting in cell membrane damage.

Probing Nanoscale Interactions of Antimicrobial Zinc Oxide Quantum Dots on Bacterial and Fungal Cell Surfaces

AbstractThe need for novel antimicrobial agents in response to a growing antibiotic and antimicrobial resistance crisis is now at a breaking point. In this work, the use of 5 nm zinc oxide quantum dots (ZnO QDs), demonstrating rapid and high antimicrobial activity against Gram‐positive methicillin‐resistant Staphylococcus aureus and highly pathogenic yeast Candida auris cells under both non‐photocatalytic and photocatalytic conditions, is showcased. Results show ZnO QDs adhere and cluster around the microbial cell surfaces, and exhibit antimicrobial response toward attached cells, resulting in the cell membrane damage. With the introduction of ultraviolet‐A light, autogenous reactive oxygen species (ROS) are produced and caused further increase in cell membrane/wall disruption, in particular Gram‐negative Escherichia coli. Nanoscale Fourier transform infrared is used to further confirm the intrinsic biochemical changes that occur with the Gram‐negative cell membrane within 30 min and spectra demonstrate that biochemical alterations are achieved for the protein and carbohydrate component of the membrane, which is a common mechanism of ROS damage. Investigation of the cell membrane–material interaction and mechanism is crucial in developing and optimizing effective antimicrobial materials in combating the rise of antimicrobial resistance.

Antimicrobial PVDF nanofiber composites with the ZnO - vermiculite - chlorhexidine based nanoparticles and their tensile properties

The poly(vinylidene fluoride) (PVDF) nanofiber materials have attracted attention due to their enhanced and exceptional nanostructural characteristics. Electrospinning PVDF based nanofiber is one of the important new materials for the rapidly growing technology development such as nanofiber based conductive tissue engineering, scaffold materials, filters and medical textiles applications. At these areas the risk of microbial contamination is very high, hence in this study the PVDF nanofiber materials with antimicrobial zinc oxide (ZnO), zinc oxide/vermiculite (ZnO/V), zinc oxide/vermiculite-chlorhexidine (ZnO/V_CH) and vermiculite-chlorhexidine (V_CH) nanofillers were prepared by electrospinning, via one-step electrospinning process. The PVDF nanofiber diameters and their orientation were investigated using scanning electron microscope (SEM). The ZnO/V_CH and V/CH nanofillers with positive ζ - potential values were incorporated into PVDF nanofibers with an average diameter of 108 nm for PVDF_ZnO/V_CH and 100 nm for PVDF_V_CH samples. In contrast, ZnO and ZnO/V nanofillers with negative ζ - potential values reacted intensively with PVDF polymer. The slightly hydrophobe character was demonstrated by water contact angle from ∼100°. The chemical interactions were evaluated by the Fourier transform infrared spectroscopy (FTIR). The presence of the β-phase in the original PVDF and the small traces of the α-phase in PVDF_ZnO and PVDF_ZnO/V samples was confirmed. In the PVDF_ZnO/V_CH and PVDF_V/CH samples where the specific interaction of PVDF chains with CH a rapid decrease in the β-phase fraction was evaluated. The mechanical properties based on the Young's modulus (E) and tensile strength (Rm) values were evaluated from the tensile test curves. Antimicrobial activity (longer than 48 h) against S. aureus and E. coli for PVDF_ZnO/V_CH and PVDF_V/CH samples was obtained.

Appraisement of antimicrobial zinc oxide nanoparticles through Cannabis Jatropha curcasa Alovera and Tinosporacordifolia leaves by green synthesis process

ZnO nanoparticles were synthesized by green synthesis using Cannabis (GSZ-1), Jatropha curcas (GSZ-2), Alovera(GSZ-3),and Tinosporacordifolia(GSZ-4) plant and leaves extract. Phase formation of ZnO nanoparticles were analyzed by X-Ray Diffraction and Rietveld Refinement. FTIR study confirms the presence of secondary metabolites like phenols and terpenoids, polyphenols, phenolic, saponin, alkaloids and glycosides in plant leaves extract working as reducing agents to shapeup ZnO nanoparticles at room temperature. SEM images provide details of the effect of plant extracts on the growth mechanism of nanoparticles and surface morphology of synthesized GSZ-1, GSZ-2, GSZ-3, and GSZ-4. EDX spectroscopy displays the ionic distribution of Zn and O in the grain of the all synthesized samples. UV-Visible spectroscopy was performed to find out the optical properties of the synthesized ZnO nanoparticles. The test cultures included in this study were pathogenic gram-positive bacterial strains Basillus cereus (BCC4391), Staphylococcus aureus (SCC2993) and one Gram-negative bacteria strain Klebsiella pneumoniae (KCC3812).

Fast and cost-effective preparation of antimicrobial zinc oxide embedded in activated carbon composite for water purification applications

Activated carbon (AC) has been widely used for water purification. However, the microorganisms attached on the AC can result in microorganism secondary contamination in the purification process. Therefore, antimicrobial AC is being developed as a promising solution. In this paper, ZnO embedded activated carbon (ZnO-AC) is synthesized with an excellent antimicrobial property. The ZnO-AC is prepared using low cost and commercially available zinc oxide powder and granular AC. ZnO is embedded in-situ on the AC through a fast and simple immersion and heating process. EDX mapping and XPS spectra showed that ZnO was evenly embedded on AC. While the ZnO-AC had relatively low level of zinc concentration of 0.593 mg/g, it achieved a high reduction ratio of 99.99% towards E. Coli. To demonstrate the robust antimicrobial property of the ZnO-AC, tap water is applied for flushing. Results showed that ZnO-AC was able to reduce 91.18% of the E. Coli even after 500 L water flushing. Meanwhile, zinc leaching analysis demonstrated that ZnO-AC is safe to be used. Thus, the prepared ZnO-AC provided a promising solution in water purification industry.

Synthesis and characterization of alginate beads encapsulated zinc oxide nanoparticles for bacteria disinfection in water

The use of polymer nanocomposites as novel materials for water remediation has emerged as a promising alternative for disinfection of bacteria contaminated water. Sodium alginate, a natural biopolymer has been investigated in this study by encapsulating antimicrobial zinc oxide nanoparticles supported bentonite. The confirmation of the alginate nanocomposites was done by use of TEM, SEM-EDS and XRD. The antimicrobial activity of the alginate nanocomposites was investigated by batch studies using surface water and synthetic bacteria contaminated water containing Staphylococcus aureus. The effect of nanocomposite amount and initial bacteria concentration has been studied. The inactivation results indicated that the nanocomposite effectively inactivated bacteria in both the synthetic and surface water. With an amount of 0.5 g of the nanocomposites, no bacteria was observed in the water after 70 min of contact time with initial bacteria concentration of 200 cfu/ml for synthetic water and within a min, no bacteria was observed in the water for surface water. It is worth noting that 200 cfu/ml is the bacteria concentration range in which environmental water is likely to contain. Therefore, the results of this study have indicated that the alginate nanocomposites can be deemed as a potential antimicrobial agent for water disinfection.

Synthesis of zinc oxide nanocomposites using poly (ionic liquids) based on quaternary ammonium acrylamidomethyl propane sulfonate for water treatment

Antimicrobial zinc oxide (ZnO) nano-sized materials have been used as environmentally friendly nanocomposites for water treatment applications due to their superior properties. Their particle size growth in water is one of their limitations that affects their preparation as nano-sized ZnO in aqueous medium at room temperature. In the present work, poly(ionic liquid), PIL, based on quaternary ammonium salts of 2–acrylamido-2-methyl propane sulfonic acid homopolymer and its copolymer with N-vinyl pyrrolidone were used as capping agents to control the ZnO shapes and sizes. The surface charges, morphology, particle sizes and chemical structure of ZnO capped with PIL were studied as well as their antimicrobial activity. The prepared ZnO nanomaterial was used to prepare crosslinked 2–acrylamido-2-methyl propane sulfonic acid-co-acrylonitrile nanocomposites to apply as adsorbent for methylene blue dye from water as harmful organic pollutants. The ZnO composites achieved high adsorption removal rate for 3000mg/L of MB from water during 20min.

A physiologically based pharmacokinetic model for the broad-spectrum antimicrobial zinc pyrithione: I. Development and verification

ABSTRACTThe broad-spectrum antimicrobial zinc pyrithione (ZnPT) is used in numerous products ranging from in-can preservative/mildicide in paints to antidandruff shampoo. Although products containing ZnPT have a long history of safe use, regulatory agencies routinely set limits of exposure based upon toxicological considerations. The objective of this study was to create a physiologically based pharmacokinetic (PBPK) model for ZnPT in the rat for improving dose-response analysis of ZnPT-induced toxicity, reversible hindlimb weakness, the endpoint that has been used as the basis for ZnPT risk assessments. A rat oral PBPK model was developed that includes compartments for plasma, liver, kidneys, muscle, brain, and rapidly and slowly perfused tissues. Pyrithione metabolism to 2-(methylsulfonyl)pyridine (MSP) and glucuronide conjugates was incorporated into the model. The model was parameterized and optimized based upon data from single-dose intravenous (iv) and oral gavage pharmacokinetic studies of radiolabeled pyrithione ([14C]PT) administered as zinc [14C]-pyrithione (Zn-[14C]PT) to adult female rats. It was further evaluated and refined using data from repeated, multidose oral gavage and dietary studies of Zn[14C]PT in the adult female rat that included measurements of plasma PT concentration, the putative toxic species. The model replicated the observed short-term elimination kinetics of PT in plasma and [14C]PT in whole blood following single doses and longer term temporal patterns of plasma and blood concentrations during repeated dosing schedules. The model also accounted for production and rapid elimination of S-glucuronide conjugates (SG) of 2-pyridinethiol and 2-pyridinethiol-1-oxide in urine, as well as production and slower elimination of MSP, the major [14C]PT species in blood within several hours following administration of ZnPT. The model provided internal dosimetry predictions for a benchmark dose (BMD) analysis of hindlimb weakness in rats, and was used to combine gavage and dietary studies into a single internal dose-response model with area under the curve (AUC) for plasma PT as the internal dose metric. This PBPK model has predictive validity for calculating internal doses of PT and/or [14C]PT from different routes of exposure in the rat.

Salmonella employs multiple mechanisms to subvert the TLR-inducible zinc-mediated antimicrobial response of human macrophages.

We aimed to characterize antimicrobial zinc trafficking within macrophages and to determine whether the professional intramacrophage pathogen Salmonella enterica serovar Typhimurium (S Typhimurium) subverts this pathway. Using both Escherichia coli and S Typhimurium, we show that TLR signaling promotes the accumulation of vesicular zinc within primary human macrophages. Vesicular zinc is delivered to E. coli to promote microbial clearance, whereas S. Typhimurium evades this response via Salmonella pathogenicity island (SPI)-1. Even in the absence of SPI-1 and the zinc exporter ZntA, S Typhimurium resists the innate immune zinc stress response, implying the existence of additional host subversion mechanisms. We also demonstrate the combinatorial antimicrobial effects of zinc and copper, a pathway that S. Typhimurium again evades. Our use of complementary tools and approaches, including confocal microscopy, direct assessment of intramacrophage bacterial zinc stress responses, specific E. coli and S Typhimurium mutants, and inductively coupled plasma mass spectroscopy, has enabled carefully controlled characterization of this novel innate immune antimicrobial pathway. In summary, our study provides new insights at the cellular level into the well-documented effects of zinc in promoting host defense against infectious disease, as well as the complex host subversion strategies employed by S Typhimurium to combat this pathway.-Kapetanovic, R., Bokil, N. J., Achard, M. E. S., Ong, C.-L. Y., Peters, K. M., Stocks, C. J., Phan, M.-D., Monteleone, M., Schroder, K., Irvine, K. M., Saunders, B. M., Walker, M. J., Stacey, K. J., McEwan, A. G., Schembri, M. A., Sweet, M. J. Salmonella employs multiple mechanisms to subvert the TLR-inducible zinc-mediated antimicrobial response of human macrophages.

Synthesis, X-ray crystal structures and thermal analyses of some new antimicrobial zinc complexes: New configurations and nano-size structures

Some new five coordinated ZnLX2 complexes, where L is N3-Schiff base ligand obtained by condensation reaction between diethylenetriamine and (E)-3-(2-nitrophenyl)acrylaldehyde and X (Cl−, Br−, I−, N3− and NCS−), were synthesized and characterized by FT-IR, 1H and 13CNMR, UV–visible, ESI-mass spectra and molar conductivity measurements. The structures of zinc iodide and thiocyanate complexes were determined by X-ray crystallographic analysis. The X-ray results showed that the Zn (II) center in these complexes is five-coordinated in a distorted trigonal–bipyramidal configuration. Zinc iodide and thiocyanate complexes crystallize in the monoclinic and triclinic systems with space groups of C2/c and P1- with eight and two molecules per unit cell respectively. The crystal packing of the complexes consists of intermolecular interactions such as C–H…O and C–H…I, C–H···S, N…O, together with π–π stacking and some other unexpected interactions. The mentioned interactions cause three-dimensional supramolecular structure in the solid state. Zinc complexes were also prepared in nano-structure by sonochemical method confirmed by XRD, SEM and TEM analyses. Moreover, ZnO nanoparticles were synthesized by direct thermolysis of zinc iodide complex. Furthermore, antimicrobial and thermal properties of the compounds were completely investigated.

Cytotoxicity of cultured macrophages exposed to antimicrobial zinc oxide (ZnO) coatings on nanoporous aluminum oxide membranes

Zinc oxide (ZnO) is a widely used commercial material that is finding use in wound healing applications due to its antimicrobial properties. Our study demonstrates a novel approach for coating ZnO with precise thickness control onto 20 nm and 100 nm pore diameter anodized aluminum oxide using atomic layer deposition (ALD). ZnO was deposited throughout the nanoporous structure of the anodized aluminum oxide membranes. An 8 nm-thick coating of ZnO, previously noted to have antimicrobial properties, was cytotoxic to cultured macrophages. After 48 h, ZnO-coated 20 nm and 100 nm pore anodized aluminum oxide significantly decreased cell viability by ≈65% and 54%, respectively, compared with cells grown on uncoated anodized aluminum oxide membranes and cells grown on tissue culture plates. Pore diameter (20–200 nm) did not influence cell viability.

An antimicrobial zinc based molecule for cross linking poly-acrylic acid

A system for incorporating antimicrobial zinc into polymeric materials, in particular hydrogel type polymers has been developed. Zn(Bipy-(MMOES)2) a zinc carboxylate monomer was designed with the purpose of mimicking commercial cross linking agents such as ethylene glycol diacrylate, as well as containing antimicrobial zinc ions (Zn2+), with the intention that it can be used to cross link into any polymeric material, the example here being polyacrylic acid. Two systems were studied: a homopolymer of the Zn(Bipy-(MMOES)2) and copolymers of Zn(Bipy-(MMOES)2) with acrylic acid (AA). The AA – Zn(Bipy-(MMOES)2) produced water swellable polymers which retained antimicrobial activity. The ability of the polymers to release the zinc ions was shown to be pH responsive and the leachate analysed to give a proposed mechanism of action. The Zn(Bipy-(MMOES)2) monomer and polymers have shown antibacterial activity against both gram positive Methicillin susceptible staphylococcus aureus (MSSA 476) and gram negative Pseudomonas aeruginosa (PA01).

The topical antimicrobial zinc pyrithione is a heat shock response inducer that causes DNA damage and PARP-dependent energy crisis in human skin cells

The differentiated epidermis of human skin serves as an essential barrier against environmental insults from physical, chemical, and biological sources. Zinc pyrithione (ZnPT) is an FDA-approved microbicidal agent used worldwide in clinical antiseptic products, over-the-counter topical antimicrobials, and cosmetic consumer products including antidandruff shampoos. Here we demonstrate for the first time that cultured primary human skin keratinocytes and melanocytes display an exquisite vulnerability to nanomolar concentrations of ZnPT resulting in pronounced induction of heat shock response gene expression and impaired genomic integrity. In keratinocytes treated with nanomolar concentrations of ZnPT, expression array analysis revealed massive upregulation of genes encoding heat shock proteins (HSPA6, HSPA1A, HSPB5, HMOX1, HSPA1L, and DNAJA1) further confirmed by immunodetection. Moreover, ZnPT treatment induced rapid depletion of cellular ATP levels and formation of poly(ADP-ribose) polymers. Consistent with an involvement of poly(ADP-ribose) polymerase (PARP) in ZnPT-induced energy crisis, ATP depletion could be antagonized by pharmacological inhibition of PARP. This result was independently confirmed using PARP-1 knockout mouse embryonic fibroblasts that were resistant to ATP depletion and cytotoxicity resulting from ZnPT exposure. In keratinocytes and melanocytes, single-cell gel electrophoresis and flow cytometric detection of gamma-H2A.X revealed rapid induction of DNA damage in response to ZnPT detectable before general loss of cell viability occurred through caspase-independent pathways. Combined with earlier experimental evidence that documents penetration of ZnPT through mammalian skin, our findings raise the possibility that this topical antimicrobial may target and compromise keratinocytes and melanocytes in intact human skin.