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Las microalgas pueden crecer y desarrollar biopelículas sobre diferente tipo de construcciones, p... more Las microalgas pueden crecer y desarrollar biopelículas sobre diferente tipo de construcciones, pudiendo afectarlas estéticamente y provocar su deterioro superficial. En este trabajo se evaluó el efecto alguicida de diferentes tratamientos superficiales para prevenir la formación de biopelículas fototróficas en superficies de hormigón. Las superficies fueron tratadas utilizando solución de base acuosa sólo con tensioactivos (papeta) y adicionada con timol al 1% y al 2 %. El efecto alguicida se evaluó sobre papel de filtro y probetas de hormigón, dejándose en ambos casos, un set de muestras control, sin tratamiento. El inóculo utilizado en los ensayos fue una comunidad de algas, aislada de construcciones de hormigón. Las muestras se rociaron con una solución de la comunidad en una concentración de ≈4.106 algas mL-1. Posteriormente, fueron incubadas bajo condiciones controladas de fotoperíodo y temperatura (16:8 h de luz: oscuridad, 25ºC) durante 28 días, registrándose resultados parciales de las observaciones semanalmente. Todos los tratamientos empleados inhibieron el crecimiento algal tanto en los ensayos de papel de filtro como en las probetas de hormigón. Estos tratamientos superficiales serían potencialmente útiles para realizar limpiezas que impidan la formación de biopelículas fototróficas sobre edificaciones históricas.
El mausoleo de Yalour es un monumento realizado en hormigón armado martelinado, ubicado en un lot... more El mausoleo de Yalour es un monumento realizado en hormigón armado martelinado, ubicado en un lote especial cedido por el Consejo Deliberante, diseñado por el ingeniero platense Enrique Boudet y construido por Armando J. Frehner entre 1931 y 1932, destacándose en el frente una escultura de una escena marina. Actualmente, el mausoleo se encuentra uniformemente cubierto por una pátina negra, con manchas conspicuas de tono más claro. El objetivo de este trabajo fue caracterizar la pátina y evaluar los procedimientos de limpieza más aptos para su intervención final. Para ello: i) se tomaron muestras de las paredes y de los vidrios del mausoleo que se observaron en microscopio óptico, de barrido de electrones y de epifluorescencia e ii) se ensayaron metodologías de limpieza en laboratorio e “in situ”. Primero se cepilló en seco la superficie, luego una parte se lavó sólo con detergente neutro, otra con detergente neutro y aplicación de cloro, y otra con aplicación de papeta AB57 modifica...
Journal of Building Engineering
Abstract The chemicals added to paints used to prevent biofilms on structural materials, contains... more Abstract The chemicals added to paints used to prevent biofilms on structural materials, contains chemical products that in general, also have toxic effects on the environment. Plants synthesize secondary metabolites which have antimicrobial properties and that may be a sustainable alternative to traditional biocides. The antimicrobial and algaecide effect of natural compounds of vegetal origin such as isoeugenol, carvacrol and vainillic acid was evaluated in a laboratory test by agar diffusion method and the microatmosphere technique respectively. As antimicrobials, the compounds exerted a moderate to high activity. Vanillic acid was the least effective, followed by isoeugenol, and being carvacrol the most efficient. In the case of algae, the three compounds produced a decrease in the algal growth with respect to the control. Due to these results, carvacrol and isoeugenol were incorporated separately in an exterior waterborne paint at a concentration of 2 % w/w. Samples painted with these formulations were not colonised by algae indicating that these compounds could be used as biocides in paint formulations.
Journal of Water Supply: Research and Technology—AQUA, 2015
We have analyzed the structure and diversity of bacterial biofilms formed on different water dist... more We have analyzed the structure and diversity of bacterial biofilms formed on different water distribution materials in the absence and in the presence of 5 mg/L of arsenic(V). Three commercial metals (cast iron, zinc and copper) and polypropylene were used as substrata for biofilm formation. Biofilms were observed using scanning electron microscopy. Microbial ecology techniques (DNA amplification by polymerase chain reaction and denaturing gradient gel electrophoresis) were applied to study the bacterial community attached to each substratum. The presence of arsenictolerant bacteria was investigated. Microscopic observations showed that biofilm development was greater on those coupons exposed to the arsenic-containing water. The presence of arsenic also induced qualitative and quantitative changes in the planktonic bacterial community. Clustering analysis of the sessile community profiles showed that the nature of the substrata was a more important factor for the establishment of the community than the presence of arsenic in water. Culturable arsenic-tolerant bacteria were obtained from most of the biofilms. The genetic diversity of the community adapted to the presence of the contaminant was less affected by the high concentration of arsenic(V) in the culture, reflecting the presence of populations adapted to the contaminant.
Matéria (Rio de Janeiro)
The rise of nanotechnology has allowed the development of several inorganic nanoparticles with st... more The rise of nanotechnology has allowed the development of several inorganic nanoparticles with strong biocidal properties against bacteria, fungi, and viruses. Among them, silver nanoparticles (AgNPs) stand out as one of the most promising antimicrobial nanomaterials. Graphene oxide (GO) is another attractive nanomaterial with antimicrobial properties. Although the antimicrobial effect of AgNPs and GO is known, the development of hybrid materials of GO-AgNPs has considerable interest in various applications since they may exhibit synergistic bactericidal properties that exceed the yields of the individual components. The aims of this work were to evaluate the antimicrobial activity and anti-adhesion properties of AgNPs and GO-AgNPs nanocomposites for potential applications in antimicrobial coatings. The antimicrobial activity was tested by agar diffusion method. It was found that activity varied according to the synthesis procedure of the nanomaterials. Pseudomonas aeruginosa, Bacillus cereus and Kokuria rhizophila were the most susceptible strains. The nanocomposite GO-AgNPs synthetized using the ex-situ method exhibited the highest antibacterial activity against all the assayed strains. Similar results were obtained for bacterial adhesion inhibition tests. Thus, GO-AgNPs nanohybrids could be applied as antibacterial coatings to prevent bacterial biofilm development.
Journal of Coatings Technology and Research
To eliminate and prevent the formation of phototrophic biofilms on painted walls, chemicals are a... more To eliminate and prevent the formation of phototrophic biofilms on painted walls, chemicals are added to paints. These chemicals, in general, also have toxic effects on the environment. Plants synthesize secondary metabolites which have antimicrobial properties and that may be a sustainable alternative to traditional biocides. In this work, algal species isolated from biofilms formed on deteriorated painted surfaces were taxonomically identified. Observations with the optical microscope revealed the presence of mixed biofilms composed of algae belonging to the Cyanophyta, Chlorophyta, and Streptophyta divisions. The algaecide effect of natural compounds of vegetal origin such as anisole, eugenol, guaiacol, and thymol was evaluated by the microatmosphere technique. Growth inhibition of phototrophic organisms was obtained with thymol in all the concentrations used. Eugenol and guaiacol showed a total growth inhibition at the highest concentration assayed (300 lmol cm À2) and a decrease in growth at 40 lmol cm À2 , while anisole did not exert any inhibitory action at the assayed concentrations. Due to these results, eugenol, thymol, and guaiacol were incorporated in an exterior waterborne paint at a concentration of 2%. Samples painted with these formulations were not colonized by algae, indicating that these compounds could be used as biocides in paint formulations.
Journal of the Mechanical Behavior of Biomedical Materials
Journal of Water Supply: Research and Technology—AQUA, 2015
Las microalgas pueden crecer y desarrollar biopelículas sobre diferente tipo de construcciones, p... more Las microalgas pueden crecer y desarrollar biopelículas sobre diferente tipo de construcciones, pudiendo afectarlas estéticamente y provocar su deterioro superficial. En este trabajo se evaluó el efecto alguicida de diferentes tratamientos superficiales para prevenir la formación de biopelículas fototróficas en superficies de hormigón. Las superficies fueron tratadas utilizando solución de base acuosa sólo con tensioactivos (papeta) y adicionada con timol al 1% y al 2 %. El efecto alguicida se evaluó sobre papel de filtro y probetas de hormigón, dejándose en ambos casos, un set de muestras control, sin tratamiento. El inóculo utilizado en los ensayos fue una comunidad de algas, aislada de construcciones de hormigón. Las muestras se rociaron con una solución de la comunidad en una concentración de ≈4.106 algas mL-1. Posteriormente, fueron incubadas bajo condiciones controladas de fotoperíodo y temperatura (16:8 h de luz: oscuridad, 25ºC) durante 28 días, registrándose resultados parciales de las observaciones semanalmente. Todos los tratamientos empleados inhibieron el crecimiento algal tanto en los ensayos de papel de filtro como en las probetas de hormigón. Estos tratamientos superficiales serían potencialmente útiles para realizar limpiezas que impidan la formación de biopelículas fototróficas sobre edificaciones históricas.
El mausoleo de Yalour es un monumento realizado en hormigón armado martelinado, ubicado en un lot... more El mausoleo de Yalour es un monumento realizado en hormigón armado martelinado, ubicado en un lote especial cedido por el Consejo Deliberante, diseñado por el ingeniero platense Enrique Boudet y construido por Armando J. Frehner entre 1931 y 1932, destacándose en el frente una escultura de una escena marina. Actualmente, el mausoleo se encuentra uniformemente cubierto por una pátina negra, con manchas conspicuas de tono más claro. El objetivo de este trabajo fue caracterizar la pátina y evaluar los procedimientos de limpieza más aptos para su intervención final. Para ello: i) se tomaron muestras de las paredes y de los vidrios del mausoleo que se observaron en microscopio óptico, de barrido de electrones y de epifluorescencia e ii) se ensayaron metodologías de limpieza en laboratorio e “in situ”. Primero se cepilló en seco la superficie, luego una parte se lavó sólo con detergente neutro, otra con detergente neutro y aplicación de cloro, y otra con aplicación de papeta AB57 modifica...
Journal of Building Engineering
Abstract The chemicals added to paints used to prevent biofilms on structural materials, contains... more Abstract The chemicals added to paints used to prevent biofilms on structural materials, contains chemical products that in general, also have toxic effects on the environment. Plants synthesize secondary metabolites which have antimicrobial properties and that may be a sustainable alternative to traditional biocides. The antimicrobial and algaecide effect of natural compounds of vegetal origin such as isoeugenol, carvacrol and vainillic acid was evaluated in a laboratory test by agar diffusion method and the microatmosphere technique respectively. As antimicrobials, the compounds exerted a moderate to high activity. Vanillic acid was the least effective, followed by isoeugenol, and being carvacrol the most efficient. In the case of algae, the three compounds produced a decrease in the algal growth with respect to the control. Due to these results, carvacrol and isoeugenol were incorporated separately in an exterior waterborne paint at a concentration of 2 % w/w. Samples painted with these formulations were not colonised by algae indicating that these compounds could be used as biocides in paint formulations.
Journal of Water Supply: Research and Technology—AQUA, 2015
We have analyzed the structure and diversity of bacterial biofilms formed on different water dist... more We have analyzed the structure and diversity of bacterial biofilms formed on different water distribution materials in the absence and in the presence of 5 mg/L of arsenic(V). Three commercial metals (cast iron, zinc and copper) and polypropylene were used as substrata for biofilm formation. Biofilms were observed using scanning electron microscopy. Microbial ecology techniques (DNA amplification by polymerase chain reaction and denaturing gradient gel electrophoresis) were applied to study the bacterial community attached to each substratum. The presence of arsenictolerant bacteria was investigated. Microscopic observations showed that biofilm development was greater on those coupons exposed to the arsenic-containing water. The presence of arsenic also induced qualitative and quantitative changes in the planktonic bacterial community. Clustering analysis of the sessile community profiles showed that the nature of the substrata was a more important factor for the establishment of the community than the presence of arsenic in water. Culturable arsenic-tolerant bacteria were obtained from most of the biofilms. The genetic diversity of the community adapted to the presence of the contaminant was less affected by the high concentration of arsenic(V) in the culture, reflecting the presence of populations adapted to the contaminant.
Matéria (Rio de Janeiro)
The rise of nanotechnology has allowed the development of several inorganic nanoparticles with st... more The rise of nanotechnology has allowed the development of several inorganic nanoparticles with strong biocidal properties against bacteria, fungi, and viruses. Among them, silver nanoparticles (AgNPs) stand out as one of the most promising antimicrobial nanomaterials. Graphene oxide (GO) is another attractive nanomaterial with antimicrobial properties. Although the antimicrobial effect of AgNPs and GO is known, the development of hybrid materials of GO-AgNPs has considerable interest in various applications since they may exhibit synergistic bactericidal properties that exceed the yields of the individual components. The aims of this work were to evaluate the antimicrobial activity and anti-adhesion properties of AgNPs and GO-AgNPs nanocomposites for potential applications in antimicrobial coatings. The antimicrobial activity was tested by agar diffusion method. It was found that activity varied according to the synthesis procedure of the nanomaterials. Pseudomonas aeruginosa, Bacillus cereus and Kokuria rhizophila were the most susceptible strains. The nanocomposite GO-AgNPs synthetized using the ex-situ method exhibited the highest antibacterial activity against all the assayed strains. Similar results were obtained for bacterial adhesion inhibition tests. Thus, GO-AgNPs nanohybrids could be applied as antibacterial coatings to prevent bacterial biofilm development.
Journal of Coatings Technology and Research
To eliminate and prevent the formation of phototrophic biofilms on painted walls, chemicals are a... more To eliminate and prevent the formation of phototrophic biofilms on painted walls, chemicals are added to paints. These chemicals, in general, also have toxic effects on the environment. Plants synthesize secondary metabolites which have antimicrobial properties and that may be a sustainable alternative to traditional biocides. In this work, algal species isolated from biofilms formed on deteriorated painted surfaces were taxonomically identified. Observations with the optical microscope revealed the presence of mixed biofilms composed of algae belonging to the Cyanophyta, Chlorophyta, and Streptophyta divisions. The algaecide effect of natural compounds of vegetal origin such as anisole, eugenol, guaiacol, and thymol was evaluated by the microatmosphere technique. Growth inhibition of phototrophic organisms was obtained with thymol in all the concentrations used. Eugenol and guaiacol showed a total growth inhibition at the highest concentration assayed (300 lmol cm À2) and a decrease in growth at 40 lmol cm À2 , while anisole did not exert any inhibitory action at the assayed concentrations. Due to these results, eugenol, thymol, and guaiacol were incorporated in an exterior waterborne paint at a concentration of 2%. Samples painted with these formulations were not colonized by algae, indicating that these compounds could be used as biocides in paint formulations.
Journal of the Mechanical Behavior of Biomedical Materials
Journal of Water Supply: Research and Technology—AQUA, 2015