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Authors
Advisor(s)
Abstract(s)
Em diferentes áreas, há necessidade de garantir ambientes higienicamente seguros que
permitam a proteção contínua através da redução de contaminantes microbianos e agentes
patogénicos. Novas soluções têm sido desenvolvidas nos últimos anos para resolver este
problema, entre as quais se incluem os sistemas de fotocatálise. O sistema Pure health
consiste em revestimentos com dióxido de titânio (TiO2). A atividade antibacteriana de TiO2
fotocatalítico baseia-se na reação de oxidação produzida pela sua irradiação, utilizando
lâmpadas fluorescentes de espetro solar, a interação entre a radiação e o revestimento origina
radicais hidroxilo e iões superóxido que são eficazes contra bactérias. Estes materiais podem
ser aplicados em ambientes ao ar livre, em espaços interiores e áreas públicas (praças,
hospitais, escolas, aeroportos). Neste estudo, a eficiência (redução microbiana) de materiais
como PVC e cerâmica revestidos com TiO2 foi testada, contra vários agentes patogénicos
relevantes, frequentemente encontrados em ambientes clínicos e alimentares: Escherichia
coli, Staphylococcus aureus, Acinetobacter baumannii, Listeria monocytogenes,
Pseudomonas aeruginosa e Salmonella spp..
As amostras de PVC com e sem revestimento foram analisadas por microscopia eletrónica de
varrimento. As imagens obtidas evidenciam uma “ película” no material com revestimento, a
qual não é observada no material controlo.
O material em estudo foi implementado numa cantina, sendo efetuadas amostragens, ao longo
de duas semanas, para avaliar o impacto do revestimento em ambiente real. Tendo como
principal objetivo determinar a eficácia antimicrobiana dos revestimentos de diferentes
matrizes (PVC e cerâmica), foram realizados ensaios experimentais utilizando como
metodologia a ISO 22196:2007. Em geral, de 0,4 ml de um inoculo padrão (105 UFC / cm2)
de cada microrganismo foi aplicado sobre uma área fixa do material e submetido à luz,
durante 24 horas. A redução da carga microbiana durante este período foi monitorada e a
eficiência antibacteriana determinada. Ao mesmo tempo foram testados: um controlo não
exposto à luz com revestimento ativo e dois controlos, com o mesmo material sem
revestimento ativo (com e sem luz). Para todos os microrganismos investigados, foram
observadas reduções significativas, entre 1 e 2 ciclos logarítmicos dependendo do material e
bactéria em estudo.
In different fields, there is a need to ensure hygienically safe environments to ensure continuous protection by reducing microbial contaminants and pathogens. New solutions have been developed in recent years to solve this problem, among which photocatalytic systems are include. Pure health system consists of titanium dioxide with coatings (TiO2). The antibacterial activity of the photocatalytic TiO2 is based on the oxidation reaction produced by it’s irradiation using fluorescent lamps solar spectrum. The interaction between the radiation and the coating produces hydroxyl radicals and superoxide ions which are effective against bacteria. These materials can be applied in outdoor environments, indoor and public areas (parks, hospitals, schools, airports). In this study, the efficiency (microbial reduction) of materials such as PVC and coated ceramic TiO2 were tested against several important pathogens commonly encountered in clinical and food environments: Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii, Listeria monocytogenes, Pseudomonas aeruginosa and Salmonella spp .. In order to understand the antimicrobial effect of PVC coating, the samples of this material with and without any coating, were analyzed by scanning electron microscopy. The images obtained show a "film" in the coating material, such feature is not observed in the material control. The test material was implemented in a canteen, sampling was performed over two weeks to assess the impact of the coating in a real situation. To determine the antimicrobial effectiveness of coatings of different matrices (PVC and ceramic) experimental tests were performed using the standard methodology described in ISO 22196: 2007. In general, 0.4 ml of a standard inoculum (105 CFU / cm2) of each organism was applied onto a fixed area of the material and subjected to light for 24 hours. The reduction of the microbial load during this period was monitored and the antibacterial efficiency determined. At the same time were also tested: a control not exposed to light with active coating and two controls with the same materials without active coating (exposed and not exposed to light). For all the organisms investigated, significant reductions were observed between 1 and 2 logarithmic cycles depending on the material and bacteria in study.
In different fields, there is a need to ensure hygienically safe environments to ensure continuous protection by reducing microbial contaminants and pathogens. New solutions have been developed in recent years to solve this problem, among which photocatalytic systems are include. Pure health system consists of titanium dioxide with coatings (TiO2). The antibacterial activity of the photocatalytic TiO2 is based on the oxidation reaction produced by it’s irradiation using fluorescent lamps solar spectrum. The interaction between the radiation and the coating produces hydroxyl radicals and superoxide ions which are effective against bacteria. These materials can be applied in outdoor environments, indoor and public areas (parks, hospitals, schools, airports). In this study, the efficiency (microbial reduction) of materials such as PVC and coated ceramic TiO2 were tested against several important pathogens commonly encountered in clinical and food environments: Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii, Listeria monocytogenes, Pseudomonas aeruginosa and Salmonella spp .. In order to understand the antimicrobial effect of PVC coating, the samples of this material with and without any coating, were analyzed by scanning electron microscopy. The images obtained show a "film" in the coating material, such feature is not observed in the material control. The test material was implemented in a canteen, sampling was performed over two weeks to assess the impact of the coating in a real situation. To determine the antimicrobial effectiveness of coatings of different matrices (PVC and ceramic) experimental tests were performed using the standard methodology described in ISO 22196: 2007. In general, 0.4 ml of a standard inoculum (105 CFU / cm2) of each organism was applied onto a fixed area of the material and subjected to light for 24 hours. The reduction of the microbial load during this period was monitored and the antibacterial efficiency determined. At the same time were also tested: a control not exposed to light with active coating and two controls with the same materials without active coating (exposed and not exposed to light). For all the organisms investigated, significant reductions were observed between 1 and 2 logarithmic cycles depending on the material and bacteria in study.