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As moedas são um dos objetos mais trocados diariamente em todo o mundo. Este facto torna-as um possível vetor de transmissão de micro-organismos, incluindo bactérias, fungos e vírus patogénicos. Apesar de existir um efeito de morte por contacto entre as bactérias e o cobre, um dos materiais usados na produção de moedas, alguns estudos indicam que estes micro-organismos conseguem sobreviver na sua superfície durante vários dias. Para além disso, o efeito da topografia das moedas na colonização bacteriana não foi ainda abordado pela comunidade científica.
O objetivo desta dissertação é determinar qualitativamente a influência de parâmetros topográficos, geométricos e físicos, na presença bacteriana em moedas de Euro, portuguesas e estrangeiras. Para isso, caracterizou-se o perfil de superfície de várias moedas determinando valores para os diferentes parâmetros; melhorou-se e utilizou-se equipamento dedicado para mimetizar o uso quotidiano das moedas; e, recorrendo a um microscópio de fluorescência, verificou-se a disposição das células bacterianas nas moedas ensaiadas.
A disposição das células na superfície das moedas permitiu identificar qualitativamente os parâmetros topográficos mais influentes na adesão bacteriana. Desta forma sugere-se a possibilidade de criar moedas com menor probabilidade de adesão alterando as especificações do processo de cunhagem.
Coins are one of the most daily exchanged items in the entire world. This fact makes them a potential fomite for the transmission of pathogens, including bacteria, fungi and virus. Although there is an effect of death by contact between bacterial cells and copper, one of the most used materials in coin production, some studies indicate that these microorganisms can survive several days in its surface. Additionally, the effect of surface topography hasn’t yet been referred by the scientific community. This dissertation’s objective is to understand the influence that certain topographical parameters, geometric and physical, have on the bacterial presence in Euro coins, Portuguese and foreign. For that, the surface profile of coins was characterized determining the values for the different parameters; dedicated equipment for simulating the daily use of coins was improved and used; and, with a fluorescence microscope, bacterial cells disposition was assessed. The disposition of the cells on the surface of coins allowed the qualitative identification of the most influential topographical parameters for bacterial adhesion. Thus, this suggests that it is possible to create coins with less potential for adhesion altering the specifications of the mintage process.
Coins are one of the most daily exchanged items in the entire world. This fact makes them a potential fomite for the transmission of pathogens, including bacteria, fungi and virus. Although there is an effect of death by contact between bacterial cells and copper, one of the most used materials in coin production, some studies indicate that these microorganisms can survive several days in its surface. Additionally, the effect of surface topography hasn’t yet been referred by the scientific community. This dissertation’s objective is to understand the influence that certain topographical parameters, geometric and physical, have on the bacterial presence in Euro coins, Portuguese and foreign. For that, the surface profile of coins was characterized determining the values for the different parameters; dedicated equipment for simulating the daily use of coins was improved and used; and, with a fluorescence microscope, bacterial cells disposition was assessed. The disposition of the cells on the surface of coins allowed the qualitative identification of the most influential topographical parameters for bacterial adhesion. Thus, this suggests that it is possible to create coins with less potential for adhesion altering the specifications of the mintage process.
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Moedas Bactérias Colonização Parâmetros Topográficos
