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Vital VG, Silva MR, Santos VT, Lobo FG, Xander P, Zauli RC, Moraes CB, Freitas-Junior LH, Barbosa CG, Pellosi DS, Silva RAG, Paganotti A, Vasconcellos SP. Micro-Addition of Silver to Copper: One Small Step in Composition, a Change for a Giant Leap in Biocidal Activity. Materials (Basel) 2024; 17:917. [PMID: 38399167 PMCID: PMC10890504 DOI: 10.3390/ma17040917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/01/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024]
Abstract
The use of copper as an antimicrobial agent has a long history and has gained renewed interest in the context of the COVID-19 pandemic. In this study, the authors investigated the antimicrobial properties of an alloy composed of copper with a small percentage of silver (Cu-0.03% wt.Ag). The alloy was tested against various pathogens, including Escherichia coli, Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and the H1N1 virus, using contact exposure tests. Results showed that the alloy was capable of inactivating these pathogens in two hours or less, indicating its strong antimicrobial activity. Electrochemical measurements were also performed, revealing that the small addition of silver to copper promoted a higher resistance to corrosion and shifted the formation of copper ions to higher potentials. This shift led to a slow but continuous release of Cu2+ ions, which have high biocidal activity. These findings show that the addition of small amounts of silver to copper can enhance its biocidal properties and improve its effectiveness as an antimicrobial material.
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Affiliation(s)
- Vitor G. Vital
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas—ICAQF, Universidade Federal de São Paulo—UNIFESP, Diadema 09913-030, Brazil (P.X.); (R.C.Z.)
| | - Márcio R. Silva
- Department of Research and Development, Termomecanica São Paulo S.A., São Bernardo do Campo 09612-000, Brazil
| | - Vinicius T. Santos
- Department of Research and Development, Termomecanica São Paulo S.A., São Bernardo do Campo 09612-000, Brazil
| | - Flávia G. Lobo
- Department of Research and Development, Termomecanica São Paulo S.A., São Bernardo do Campo 09612-000, Brazil
| | - Patrícia Xander
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas—ICAQF, Universidade Federal de São Paulo—UNIFESP, Diadema 09913-030, Brazil (P.X.); (R.C.Z.)
| | - Rogéria C. Zauli
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas—ICAQF, Universidade Federal de São Paulo—UNIFESP, Diadema 09913-030, Brazil (P.X.); (R.C.Z.)
| | - Carolina B. Moraes
- Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo 05508-000, Brazil
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Lucio H. Freitas-Junior
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Cecíla G. Barbosa
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Diogo S. Pellosi
- Instituto de Química, Universidade Federal do Paraná, Curitiba 81531-980, Brazil
| | - Ricardo A. G. Silva
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas—ICAQF, Universidade Federal de São Paulo—UNIFESP, Diadema 09913-030, Brazil (P.X.); (R.C.Z.)
| | - André Paganotti
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas—ICAQF, Universidade Federal de São Paulo—UNIFESP, Diadema 09913-030, Brazil (P.X.); (R.C.Z.)
| | - Suzan P. Vasconcellos
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas—ICAQF, Universidade Federal de São Paulo—UNIFESP, Diadema 09913-030, Brazil (P.X.); (R.C.Z.)
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Perry EB, Discepolo DR, Liang SY, Scott M, Williamson K, Bender KS. Biocidal effects of a wipe-down procedure using common veterinary cleansers on microbial burden within working canine exterior coats. Front Vet Sci 2023; 10:1219249. [PMID: 37565083 PMCID: PMC10411539 DOI: 10.3389/fvets.2023.1219249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/19/2023] [Indexed: 08/12/2023] Open
Abstract
Introduction Recent work demonstrating reduction of aerosolized contamination via a wipe-down procedure using common veterinary antiseptics offers promise regarding health concerns associated with cross-contamination from working canines to humans. While mechanical reduction can be achieved via a wipe-down procedure, the biocidal impact on flora within the exterior coat is unknown. Methodology This study assessed the biocidal impact of antiseptics on the exterior bacterial community of the canine. Lint-free towels were saturated with 2% chlorhexidine gluconate scrub, or 7.5% povidone-iodine scrub diluted at a 1:4 ratio. Treatments were rotated across the dorsal aspect of kennel housed Foxhounds (n = 30). Sterile swabs were collected in triplicate prior to, and following wipe down, stored in Amies solution at 4°C, plated onto nutrient agar and reduction in colony forming units (CFU) was measured across both treatments. Statistical analysis utilizing PROC GLM examined effects of treatment (p ≤ 0.05). Molecular analysis of the 16S rRNA gene was completed for 3 hounds. Results Reduction in CFU was measured (p < 0.001) for both antiseptics. Qualitative molecular data indicated that both antiseptics had a biocidal effect on the dominant microbial community on the exterior coat with gram-positive, spore-forming taxa predominating post-treatment. Conclusion Effective wipe-down strategies using common veterinary cleansers should be further investigated and incorporated to safeguard working canine health and prevent cross-contamination of human personnel.
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Affiliation(s)
- Erin B. Perry
- Department of Animal Science Food and Nutrition, Southern Illinois University, Carbondale, IL, United States
| | - Dakota R. Discepolo
- Department of Animal Science Food and Nutrition, Southern Illinois University, Carbondale, IL, United States
| | - Stephen Y. Liang
- Department of Emergency Medicine and Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Maurnice Scott
- Department of Animal Science Food and Nutrition, Southern Illinois University, Carbondale, IL, United States
| | - Kyleigh Williamson
- School of Biological Sciences, Microbiology Program, Southern Illinois University, Carbondale, IL, United States
| | - Kelly S. Bender
- School of Biological Sciences, Microbiology Program, Southern Illinois University, Carbondale, IL, United States
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Lejeune B, Zhang X, Sun S, Hines J, Jinn KW, Reilly AN, Clark HA, Lewis LH. Enhancing Biocidal Capability in Cuprite Coatings. ACS Biomater Sci Eng 2023; 9:4178-4186. [PMID: 37267510 PMCID: PMC10620754 DOI: 10.1021/acsbiomaterials.2c01222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 05/12/2023] [Indexed: 06/04/2023]
Abstract
The SARS-CoV-2 global pandemic has reinvigorated interest in the creation and widespread deployment of durable, cost-effective, and environmentally benign antipathogenic coatings for high-touch public surfaces. While the contact-kill capability and mechanism of metallic copper and its alloys are well established, the biocidal activity of the refractory oxide forms remains poorly understood. In this study, commercial cuprous oxide (Cu2O, cuprite) powder was rapidly nanostructured using high-energy cryomechanical processing. Coatings made from these processed powders demonstrated a passive "contact-kill" response to Escherichia coli (E. coli) bacteria that was 4× (400%) faster than coatings made from unprocessed powder. No viable bacteria (>99.999% (5-log10) reduction) were detected in bioassays performed after two hours of exposure of E. coli to coatings of processed cuprous oxide, while a greater than 99% bacterial reduction was achieved within 30 min of exposure. Further, these coatings were hydrophobic and no external energy input was required to activate their contact-kill capability. The upregulated antibacterial response of the processed powders is positively correlated with extensive induced crystallographic disorder and microstrain in the Cu2O lattice accompanied by color changes that are consistent with an increased semiconducting bandgap energy. It is deduced that cryomilling creates well-crystallized nanoscale regions enmeshed within the highly lattice-defective particle matrix. Increasing the relative proportion of lattice-defective cuprous oxide exposed to the environment at the coating surface is anticipated to further enhance the antipathogenic capability of this abundant, inexpensive, robust, and easily handled material for wider application in contact-kill surfaces.
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Affiliation(s)
- Brian
T. Lejeune
- Department
of Chemical Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Xiaoyu Zhang
- Department
of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Su Sun
- Department
of Chemical Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Julia Hines
- Department
of Chemical Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Kevin W. Jinn
- Department
of Chemical Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Ashlyn Neal Reilly
- Department
of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Heather A. Clark
- Department
of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
- Department
of Chemistry, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Laura H. Lewis
- Department
of Chemical Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
- Department
of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
- The
George J. Kostas Research Institute for Homeland Security, Northeastern University, 360 Huntington Ave, Boston, Massachusetts 02115, United States
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Olsen MR, Colliard I, Rahman T, Miyaishi TC, Harper B, Harper S, Nyman M. Hybrid Polyoxometalate Salt Adhesion by Butyltin Functionalization. ACS Appl Mater Interfaces 2021; 13:19497-19506. [PMID: 33856779 DOI: 10.1021/acsami.1c03269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Polyoxometalate (POM)-based ionic liquids, with nearly infinite compositional variations to fine-tune antimicrobial and physical properties, function as water purification filters, anticorrosion/antibacterial coatings for natural stones, self-repairing acid-resistant coatings, catalysts, and electroactive, stable solvents. By combining hydrophobic quaternary ammonium cations (QACs; tetraheptylammonium and trihexyltetradecylammonium) with butyltin-substituted polyoxotungstates [(BuSn)3(α-SiW9O37)] via repeated solvent extraction-ion exchange, we obtained phase-pure hybrid POM salts (referred to as such because they melt above room temperature). If the solvent extraction process is performed only once, then solids with high salt contamination and considerably lower melting temperatures are obtained. Solution-phase behavior, based on POM-QAC interactions, was similar for all formulations in polar and nonpolar organic solvents, as observed by X-ray scattering and multinuclear magnetic resonance spectroscopy. However, solid thin films of the butyltin-functionalized hybrid POM salts were significantly more stable and adhesive than their inorganic analogues. We attribute this to the favorable hydrophobic interactions between the butyltin groups and the QACs. All synthesized hybrid POM salts display a potent antimicrobial activity toward Escherichia coli. These studies provide fundamental form-function understanding of hybrid POM salts, based on interactions between ions in these complex hybrid phases.
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Affiliation(s)
- Morgan Rose Olsen
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
- Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - Ian Colliard
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Tasnim Rahman
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Taiki C Miyaishi
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Bryan Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States
| | - Stacey Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - May Nyman
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
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Ma Y, Yi J, Pan B, Nitin N, Sun G. Chlorine Rechargeable Biocidal N-Halamine Nanofibrous Membranes Incorporated with Bifunctional Zwitterionic Polymers for Efficient Water Disinfection Applications. ACS Appl Mater Interfaces 2020; 12:51057-51068. [PMID: 33138373 DOI: 10.1021/acsami.0c14856] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An intrinsically hydrophilic nanofibrous membrane with chlorine rechargeable biocidal and antifouling functions was prepared by using a combination of chemically bonded N-halamine moieties and zwitterionic polymers (PEI-S). The designed nanofibrous membrane, named as PEI-S@BNF-2 h, can exhibit integrated features of reduced bacterial adhesion, rechargeable biocidal activity, and easy release of killed bacteria by using mild hydrodynamic forces. The representative functional performances of the PEI-S@BNF-2 h membrane include high active chlorine capacity (>4000 ppm), large specific surface area, ease of chlorine rechargeability, long-term stability, and exceptional biocidal activity (99.9999% via contact killing). More importantly, the zwitterionic polymer moieties (PEI-S) brought robust antifouling properties to this biocidal membrane, therefore reducing the biofouling-biofilm effect and prolonging the lifetime of the filtration membrane. These attributes enable the PEI-S@BNF-2 h nanofibrous membrane to effectively disinfect the microbe-contaminated water with high fluxes (10,000 L m-2 h-1) and maintain itself clean for a long-term application.
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Affiliation(s)
- Yue Ma
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
| | - Jiyoon Yi
- Department of Food Science and Technology, University of California, Davis, California 95616, United States
| | - Bofeng Pan
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
| | - Nitin Nitin
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
- Department of Food Science and Technology, University of California, Davis, California 95616, United States
| | - Gang Sun
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
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6
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Chen A, Karanastasis A, Casey KR, Necelis M, Carone BR, Caputo GA, Palermo EF. Cationic Molecular Umbrellas as Antibacterial Agents with Remarkable Cell-Type Selectivity. ACS Appl Mater Interfaces 2020; 12:21270-21282. [PMID: 31917544 DOI: 10.1021/acsami.9b19076] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We synthesized a combinatorial library of dendrons that display a cluster of cationic charges juxtaposed with a hydrophobic alkyl chain, using the so-called "molecular umbrella" design approach. Systematically tuning the generation number and alkyl chain length enabled a detailed study of the structure-activity relationships in terms of both hydrophobic content and number of cationic charges. These discrete, unimolecular compounds display rapid and broad-spectrum bactericidal activity comparable to the activity of antibacterial peptides. Micellization was examined by pyrene emission and dynamic light scattering, which revealed that monomeric, individually solvated dendrons are present in aqueous media. The antibacterial mechanism of action is putatively driven by the membrane-disrupting nature of these cationic surfactants, which we confirmed by enzymatic assays on E. coli cells. The hemolytic activity of these dendritic macromolecules is sensitively dependent on the dendron generation and the alkyl chain length. Via structural optimization of these two key design features, we identified a leading candidate with potent broad-spectrum antibacterial activity (4-8 μg/mL) combined with outstanding hemocompatibility (up to 5000 μg/mL). This selected compound is >1000-fold more active against bacteria as compared to red blood cells, which represents one of the highest selectivity index values ever reported for a membrane-disrupting antibacterial agent. Thus, the leading candidate from this initial library screen holds great potential for future applications as a nontoxic, degradable disinfectant.
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Affiliation(s)
- Ao Chen
- Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12054, United States
| | - Apostolos Karanastasis
- Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12054, United States
| | | | | | | | | | - Edmund F Palermo
- Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12054, United States
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7
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Wang H, Jian G, Zhou W, DeLisio JB, Lee VT, Zachariah MR. Metal Iodate-Based Energetic Composites and Their Combustion and Biocidal Performance. ACS Appl Mater Interfaces 2015; 7:17363-17370. [PMID: 26161906 DOI: 10.1021/acsami.5b04589] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The biological agents that can be weaponized, such as Bacillus anthracis, pose a considerable potential public threat. Bacterial spores, in particular, are highly stress resistant and cannot be completely neutralized by common bactericides. This paper reports on synthesis of metal iodate-based aluminized electrospray-assembled nanocomposites which neutralize spores through a combined thermal and chemical mechanism. Here metal iodates (Bi(IO3)3, Cu(IO3)2, and Fe(IO3)3) act as a strong oxidizer to nanoaluminum to yield a very exothermic and violent reaction, and simultaneously generate iodine as a long-lived bactericide. These microparticle-assembled nanocomposites when characterized in terms of reaction times and temporal pressure release show significantly improved reactivity. Furthermore, sporicidal performance superior to conventional metal-oxide-based thermites clearly shows the advantages of combining both a thermal and biocidal mechanism in spore neutralization.
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Affiliation(s)
- H Wang
- †Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - G Jian
- †Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - W Zhou
- †Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - J B DeLisio
- †Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - V T Lee
- ‡Department of Cell Biology and Molecular Genetics, University of Maryland, College Park 20740, Maryland, United States
| | - M R Zachariah
- †Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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8
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Kilvington S, Lam A. Development of standardized methods for assessing biocidal efficacy of contact lens care solutions against Acanthamoeba trophozoites and cysts. Invest Ophthalmol Vis Sci 2013; 54:4527-37. [PMID: 23745008 DOI: 10.1167/iovs.13-11927] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate experimental variables in the development of standardized methods to assess the efficacy of contact lens disinfection systems against the trophozoite and cysts of Acanthamoeba spp. METHODS A. castellanii (ATCC 50370), A. polyphaga (ATCC 30461), and A. hatchetti (CDC: V573) were adapted to axenic culture and used to produce cysts either with Neff's encystment medium (NEM) or starvation on nonnutrient agar (NNA). Challenge test assays and a most probable number approach were used to compare the trophozoite and cysticidal efficacy of four multipurpose disinfectant solutions (MPDSs) and a one-step hydrogen peroxide system (with and without the neutralizing step). RESULTS With trophozoites, four of four MPDSs and the one-step peroxide system gave ≥3 log₁₀ kill for all strains 6 hours, regardless of culture medium used. Greater resistance was found against cysts, with results for MPDSs varying by species and method of cyst production. Here, 1-3 log₁₀ kill was found with NEM cysts for three of four MPDSs compared with one of four for the NNA cysts at 6 hours (A. castellanii and A. polyphaga, only). The one-step peroxide system gave 1-1.9 log₁₀ kill with NEM cysts and 0.8-1.1 for NNA cysts. Only 3% hydrogen peroxide gave total kill (>3 log₁₀) of NNA cysts at 6 hours. CONCLUSIONS A reproducible method for determining the susceptibility of Acanthamoeba trophozoites and cysts to contact lens care systems has been developed. This will facilitate assay standardization for assessing the efficacy of such products against the organism and aid development of improved disinfectant and therapeutic agents.
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Affiliation(s)
- Simon Kilvington
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom.
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9
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McCluskey DM, Smith TN, Madasu PK, Coumbe CE, Mackey MA, Fulmer PA, Wynne JH, Stevenson S, Phillips JP. Evidence for singlet-oxygen generation and biocidal activity in photoresponsive metallic nitride fullerene-polymer adhesive films. ACS Appl Mater Interfaces 2009; 1:882-887. [PMID: 20161355 PMCID: PMC2776767 DOI: 10.1021/am900008v] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The adhesive properties, as measured by bulk tack analysis, are found to decrease in blends of isomerically pure Sc3N@I(h)-C80 metallic nitride fullerene (MNF) and polystyrene-block-polyisoprene-block-polystyrene (SIS) copolymer pressure-sensitive adhesive under white light irradiation in air. The reduction of tack is attributed to the in situ generation of 1O2 and subsequent photooxidative cross-linking of the adhesive film. Comparisons are drawn to classical fullerenes C60 and C70 for this process. This work represents the first demonstration of 1O2 generating ability in the general class of MNFs (M3N@C80). Additional support is provided for the sensitizing ability of Sc3N@I(h)-C80 through the successful photooxygenation of 2-methyl-2-butene to its allylic hydroperoxides in benzene-d(6) under irradiation at 420 nm, a process that occurs at a rate comparable to that of C(60). Photooxygenation of 2-methyl-2-butene is found to be influenced by the fullerene sensitizer concentration and O2 flow rate. Molar extinction coefficients are reported for Sc3N@I(h)-C80 at 420 and 536 nm. Evaluation of the potential antimicrobial activity of films prepared in this study stemming from the in situ generation of 1O2 led to an observed 1 log kill for select Gram-positive and Gram-negative bacteria.
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Affiliation(s)
- D. Michelle McCluskey
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Tiffany N. Smith
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Praveen K. Madasu
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Curtis E. Coumbe
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Mary A. Mackey
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Preston A. Fulmer
- Chemistry Division, Naval Research Laboratory, Washington, District of Columbia 20375
| | - James H. Wynne
- Chemistry Division, Naval Research Laboratory, Washington, District of Columbia 20375
| | - Steven Stevenson
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - J. Paige Phillips
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
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10
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Abstract
Lethal dose curves were calculated using probit analysis for six disinfestants (chlorazene hydrosol, hydrogen dioxide, hydrogen peroxide, iodine, quaternary ammonium chloride, sodium hypochlorite) when applied on seven substrates (galvanized metal, stainless steel, polyethylene ground fabric, polyethylene pot plastic, pressure-treated pine, exterior latex-painted pine, raw pine) that had been inoculated with Botrytis cinerea conidia. Mortality was determined by percentage of ungerminated versus germinated conidia that had been rubbed off of a substrate onto half-strength potato dextrose agar (hPDA) 16 to 24 h previously. Based on overlapping confidence limits (95% CL) of the lethal doses resulting in 90 and 50% mortality (LD90 and LD50, respectively) and significance of slopes, differences occurred between substrates with all six disinfestants. LD90 values ranged from 0.21 to 4.54 g a.i./liter for chlorazene hydrosol, 4.99 to 40.3 g a.i./liter for hydrogen dioxide, 63.0 to 233.1 g a.i./liter for hydrogen peroxide, 0.42 to 2.45 g a.i./liter for iodine, 0.64 to 6.46 g a.i./liter for quaternary ammonium chloride, and 0.87 to 6.84 g a.i./liter for sodium hypochlorite. For hydrogen dioxide, quaternary ammonium chloride, and sodium hypochlorite, a binomial lethal dose (LDb) was calculated by plating the inverted inoculated substrates on hPDA, then recording the presence or absence of B. cinerea mycelial growth over 7 days. Lethal doses resulting in the absence of mycelial growth (LDb100) were equal to or greater than the LD90 values for most disinfestants and substrates. Results demonstrate for the six disinfestants that dose should be selected based on the substrate being disinfested of B. cinerea conidia.
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Affiliation(s)
- W E Copes
- USDA/ARS Small Fruit Experiment Station, Poplarville, MS 39470
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