Attributes of nanoparticles obtained by green synthesis for application in antifungal coatings

The green synthesis of nanoparticles based on the use of aqueous vegetable extracts islow cost, non-polluting and makes use of renewable reagents. These extracts containmetabolites that perform as reducing and stabilizing agents. In this regard, the use oftannins is promising due to their high polyphenol content. The present work proposes tosynthesize and characterize nanoparticles obtained silver and copper salts with ?tara?tannin (TT). TT is commercially available and proceeds aqueous extract of Caesalpiniaspinosa. The nanoparticles were obtained starting an aqueous solution of AgNO3 10-2 Mand Cu(NO3)2.3H2O 10-2 M to which the tannin solution was added in constantagitation. Three concentrations of TT were used: 500, 1000 and 2000 ppm. This processwas done at 60° C and pH = 7. The stability over time of these nanoparticles wasevaluated by UV-vis spectroscopy carried out at different times: 1, 30 and 60 days. Toconfirm the obtaining of the nanoparticles and observe their morphology, transmissionelectron microscopy (TEM) was applied. The synthesized nanoparticles were purified andFourier transform infrared spectroscopy (FTIR) was performed. The antifungal activity wasevaluated by the agar diffusion test (Kirby-Bauer) against the collection strains: Cladosporiumcladosporioides (MG731215), Alternaria tunuissima (MG731240) and Aspergillus versicolor (MG725821).UV-vis spectra of silver nanoparticles obtained TT solutions of 500 (NpsAg500), 1000 (NpsAg1000) and2000ppm (NpsAg2000) presented an absorption maximum around 400, 410 and 420 nm, respectively.These bands remained stable over time. In the case of copper salt the nanoparticles obtained with TTsolution of 2000ppm (NpsCu2000) showed a band at 330 nm and with 1000 and 500ppm resultedunstable. TEM micrographs confirmed the presence of quasispherical nanoparticles predominantlysmaller than 20 nm with higher frequency. FTIR spectra confirmed the strong interaction between ofthe nanoparticles and the tannin used in the synthesis. Related to the agar diffusion test, NpsCu2000was not active against the fungal strains used while the silver nanoparticles showed to be active inall cases. In this sense, NpsAg500 presented the highest inhibition zone against C. cladosporioides. Thenext step will be to formulate coatings with these nanoparticles.Fil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Deya, Marta Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Bellotti, Natalia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaXXVII International Materials Research Congress - IMRC 2018CancúnMéxicoSociedad Mexicana de Materiale

Fungal deterioration control in outdoor environments by nano-additivated waterborne paint

Biodeterioration of facades in building constructions causes economic damage. Filamentous fungi by their presence cause aesthetic damage to structural materials. In addition, its invasive growth through hyphae generates physical deterioration and due to its nutrition and excretion, they release enzymes, acids and pigments that cause chemical deterioration.To control fungal deterioration, paint additives with nanostructured biocides can be applied on facades.In addition, it is important that the nanoadditive maintains its long-term antimicrobial activity to delay fungal deterioration.The aim of this research was to assess the antifungal activity of a waterborne paint additivated with ZnO nanoparticles (ZnONPs) after 4 years exposed to the outdoor environment.Fil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Deya, Marta Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Bellotti, Natalia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaXXV Congreso Latinoamericano de Microbiología; V Congreso Paraguayo de Microbiología; IX Congreso Nacional de Bioquímica Clínica y I Congreso Paraguayo de Bioquímica y Ciencias del LaboratorioAsunciónParaguayAsociación Latinoamericana de Microbiologí

Senna occidentalis aqueous extract for the synthesis of nanoparticles with cerium, lanthanum, copper, silver and zinc salts produces stable antimicrobial agent

The use of aqueous plant extracts to obtain nanoparticles are promising due to theiraccessibility, low cost, and eco-friendliness. The green synthesis of different nanoparticles wascarried out to explore their antimicrobial potentials as bioactive components in waterbornecoating formulations. Solutions of zinc, cerium, lanthanum, copper, and silver salts at differentconcentrations were used as sources of metal ions for the synthesis process. Aqueous plantextract of Senna ocidentalis, a small shrub about 3 ft. high belonging to Leguminosae familywas used as a reducing and stabilizing agent. The nanoparticles synthesis involved the mixingof 10 ml of the extract in 90mL of each metal salt solution at 60ºC and pH 7 withconstant stirring. The nanoparticle synthesis was confirmed by UV-vis spectroscopy after 24hours. The same technique was used to assess the stability of the nanoparticles over time.The characterization of the nanoparticles by transmission electron microscopy and Fouriertransformed infrared spectroscopy showed stability after 30 days of synthesis. Theantimicrobial activity assay was performed against bacterial and fungal strains: Escherichia coli, Staphylococcus aureus, Chaetomium globosum and Alternaria alternata. These microorganisms wereselected due to their predominance and role in biodeterioration. Nanoparticles obtained with silverand copper solutions were stable. However, only the silver quasy-spherical nanoparticles showedantimicrobial activity against all tested strains.Fil: Barberia Roque, Leyanet. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Olayide, Obidi. Universidad de Lagos; NigeriaFil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Bellotti, Natalia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaXXVII Internacional Material Research Congress 2018CancúnMéxicoMaterials Research Society y Sociedad Mexicana de Materiale

Mycological studies as a tool to improve the control of building materials biodeterioration

Fungal deterioration of building materials causes economic losses due to restoration processes and because it affects the health of the people exposed. Therefore, it is necessary to obtain highly deteriorating fungal strains to carry out studies focused on biodeterioration control. The aim of this research was to study the mycobiota involved in deterioration of facades through the isolation and characterization of fungal strains. In this sense, this paper characterizes the mycobiota that contributes to the deterioration of brick and concrete present in those places. Samples were taken from bricks and concrete with visible biodeterioration of the Cathedral of La Plata and the Experimental Station of the Centro de Investigación y Desarrollo en Tecnología de Pinturas. Relative density, apparition relative frequency, and ecological category of fungi isolates were determined. The deteriorating attributes were determined by carbonate dissolution test, pigment secretion assay, acid production test and brick weight variation. Cladosporium sp., Penicillium sp. and Aspergillus sp. were the taxa with the highest apparition relative frequency and abundance. Aspergillus niger MN371276, Lasiodiplodia theobromae MN371283, Cladosporium sphaerospermum MN371394, Penicillium commune MN371392 and Arthothelium spectabile MT071822 were the strains with the highest biodeteriorant activity. These strains can be used in studies on biodeterioration control of buildings materials.Fil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Bellotti, Natalia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Deya, Marta Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería; ArgentinaFil: Cabello, Marta Noemí. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentin

Antifungal effects of Curcuma longa L. essential oil against pathogenic strains isolated from indoor air

Curcuma longa L. essential oil can be considered a natural product with strong antifungal activity due to the fungicidal and fungistatic effect. It can be used for the aeromycological control of premises where food is prepared. It is important to monitor air quality in food production facilities to achieve safe food. The objective of this work was to evaluate the antifungal activity of C. longa essential oil on potentially pathogenic and biodegradable strains isolated from the indoor of the food industry. A suspension of 106 spores/mL of the strains Aspergillus flavus, Penicillium brevicompactum and Cladosporium cladosporioides was prepared. Two natural biocides (C. longa essential oil and Cuban propolis) and two synthetic ones (antiseptic detergent and Tween 20) at different concentrations (0, 0.001, 0.1 and 1.0% v/v) were evaluated. The superficial growth of the mycelium (cm) and the germination inhibition (%) were the response variables. In addition, the minimum inhibitory concentration (MIC) of EO was determined by radial growth total inhibition (IRG) and partial sporulation inhibition (PIS). A. flavus colony diameter was decrease inversely proportional to the concentrations, and at 1% v/v it reduced more than three times its diameter, being selected as MIC since it caused IRG and PIS. Germination inhibition of the spores of the three strains was observed in relation directly proportional to the concentration of the four biocides. All spores with values similar to antiseptic detergent were inhibited by the essential oil at MIC (1%) between 41 and 55%Fil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Anaya, Matilde. Instituto de Investigaciones Para la Industria Alimentaria; CubaFil: Borges, Pedro. Instituto de Investigaciones Para la Industria Alimentaria; CubaFil: Bosch Crespo, Diana Marelys. Universidad de Salamanca; Españ

Effect of the oscillating magnetic field on airborne fungal

This study shows that some species of fungi are affected by the magnetic field, which should be taken into account in studies of airborne fungal and air quality. The aim of this paper was to evaluate the effect of the oscillating magnetic field (OMF) on the behavior of colonies of three fungi genus growth in different culture mediums. The stains were: Aspergillus niger, Cladosporium cladosporioides and Penicillium citrinum and were inoculated in 90 mm Petri dishes with: Malt Extract Agar (MEA), Sabouraud Dextrose Agar (SDA) and Czapek-Dox Agar (CDA). Was applied them OMF of 60 Hz/220 V between 1 and 5 mT during 2 h and then they were incubated 7 days to 28 °C. Colonies size (mm) every day was measured. Stimulation in the colonies size of all experimental conditions was showed; the greatest size of A. niger in MEA was notorious. It was demonstrated by statist analyze that only colonies size with 1 mT was significance respect to the control. The effect of OMF on the cellular metabolism was evidenced, as well as: less exudation and major pigmentation of P. citrinum in MEA; variation of pigmentation of A. niger and C. cladosporioides in CDA and increase of conidiogenesis of A. niger in SDA. Was concluded that the applied OMF had a major influence on size colony and mycelia pigmentation of A. niger that C. cladosporioides and P. citrinum, independently of the nutritional state according to the culture medium employed in this study.Fil: Anaya, Matilde. Grupo Empresarial de la Industria Alimentaria; CubaFil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Valdés, Oderlaise. Grupo Empresarial de la Industria Alimentaria; CubaFil: Guzmán, Tania. Universidad Tecnológica Equinoccial.; EcuadorFil: Borrego, Sofía. Archivo Nacional de la República de Cuba; Cub

Antifungal effects of Curcuma longa L. essential oil against pathogenic strains isolated from indoor air

Curcuma longa L. essential oil can be considered a natural product with strong antifungal activity due to the fungicidal and fungistatic effect. It can be used for the aeromycological control of premises where food is prepared. It is important to monitor air quality in food production facilities to achieve safe food. The objective of this work was to evaluate the antifungal activity of C. longa essential oil on potentially pathogenic and biodegradable strains isolated from the indoor of the food industry. A suspension of 106 spores/mL of the strains Aspergillus flavus, Penicillium brevicompactum and Cladosporium cladosporioides was prepared. Two natural biocides (C. longa essential oil and Cuban propolis) and two synthetic ones (antiseptic detergent and Tween 20) at different concentrations (0, 0.001, 0.1 and 1.0% v/v) were evaluated. The superficial growth of the mycelium (cm) and the germination inhibition (%) were the response variables. In addition, the minimum inhibitory concentration (MIC) of EO was determined by radial growth total inhibition (IRG) and partial sporulation inhibition (PIS). A. flavus colony diameter was decrease inversely proportional to the concentrations, and at 1% v/v it reduced more than three times its diameter, being selected as MIC since it caused IRG and PIS. Germination inhibition of the spores of the three strains was observed in relation directly proportional to the concentration of the four biocides. All spores with values similar to antiseptic detergent were inhibited by the essential oil at MIC (1%) between 41 and 55%Fil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Anaya, Matilde. Instituto de Investigaciones Para la Industria Alimentaria; CubaFil: Borges, Pedro. Instituto de Investigaciones Para la Industria Alimentaria; CubaFil: Bosch Crespo, Diana Marelys. Universidad de Salamanca; Españ

Alkyd based water-reducible anticorrosive paints and their antifungal potential

Concerns about ozone layer, contamination, fossils resources and health, has banned or restricted the use of traditionally organic solvents in paints. As a consequence, new resins that employed water as main solvent are being studied. Among these resins, alkyds are the most studied one as they can also be synthesised from natural vegetable sources, making them more acceptable. The aim of this paper was to study the anticorrosive behaviour of alkyd / polysaccharide paints containing zinc phosphate or zinc aluminum phosphate as main pigment and their performance against fungal growth. Two different PVC (pigment volume concentration) were studied. Painted panels were studied by exposition to salt spray and humidity chambers, where rusting and blistering degrees were evaluated, and by electrochemical tests (corrosion potential measurements, ionic resistances determination, linear polarization curves and polarization resistances determination). Results showed that these type of paints can be used to protect steel and that the type of pigment and the PVC are important to the protection. Besides, good selection of both also prevents fungi growth in a high humid environment.Fil: Martinez Mesa, Aliezer. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Gámez Espinosa, Erasmo Junior. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bellotti, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Deya, Marta Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Fungal deterioration of a phosphate conversion coating

El acero al carbono es un material ampliamente empleado en múltiples aplicaciones, como por ejemplo construcción, energía, electrodomésticos, transporte, entre otras. Sin embargo, su escasa resistencia a la corrosión restringe su uso en muchas otras aplicaciones. La formación de una película de conversión de fosfato sobre la superficie de acero es una técnica muy empleada para aumentar la resistencia a la corrosión del acero al carbono, especialmente durante el transporte y almacenaje del material. En estos casos, el acero podría estar expuesto a ambientes húmedos, favorables para el desarrollo de microorganismos. Muchos microorganismos son capaces de solubilizar fosfatos insolubles y los hongos son particularmente importantes en este sentido. En este trabajo se analizó, empleando medidas electroquímicas (curvas de polarización potenciodinámicas) y observación mediante lupa estereoscópica y microscopía electrónica de barrido (MEB), como se afecta la protección otorgada por dos tipos de películas de conversión de fosfato al acero al carbono, al ser expuestas al crecimiento de Aspergillus niger MN371276.Facultad de Ciencias Agrarias y Forestale

Study of UVC light action on paints

El agente más agresivo que causa degradación de las pinturas es el oxígeno, especialmente en presencia de radiación UV. La degradación es, en general de tipo oxidativa, con la incorporación de O en l estructura molecular de la resina. La radiación UVC es aquella cuya longitud de onda varía entre 100 y 280 nm y es la más dañina de las radiaciones UV, aunque no llega desde el sol hasta la superficie de la tierra debido a la acción protectora de la atmósfera. Sin embargo, puede generarse mediante lámparas adecuadas y ser utilizada como germicida o bien en ensayos acelerados de degradación por rayos UV cuando los recubrimientos están expuestos al exterior. En este trabajo se utilizó radiación UVC de una lámpara para estudiar su interacción con diferentes pinturas y seleccionar los ensayos posibles para detectar dichas interacciones, que en general producen una degradación de la resina y pérdida de las propiedades protectoras del recubrimiento.Facultad de Ciencias Agrarias y Forestale