Direct measurement of ultrasonic activity on microbial metabolism and analysis of related uncertainty

The scope of this work is to identify the relation that exists between the alterations of the bacterial metabolism and the exposition to an ultrasonic field (O'Leary et al. 1997, Piyasena et al. 2003, Brujan2004). To made this relation quantifiable they will be used repeatable and reproducible metrological methods. To obtain this result the research will be centred on 3 specific goal: 1. To realise a measurement of the ultrasonic field, generated by an ultrasonic bath, using an hydrophone calibrated specifically with the wavelengths applied (Canney et al. 2008). 2. To choose a method, through uncertainty evaluation, to expose microbes to the ultrasonic field without an excessive alteration of the generated acoustic pressure. 3. To find a method to measure bacterial viability, represented by the planktonic growth and the biofilm development, after exposure to the ultrasounds. Studying the relationship between the bacteria metabolism and ultrasonic exposure it will be possible to identify novels and more precise methods to treat bacterial colonizations. This result will be in fact useful in various fields where the bacterial presence, and in particular biofilm development, is today an unresolved problem. At the same time this research will put the basis for many further studies that will be realized applying the same methods with different bacterial species, ultrasounds exposition conditions or ultrasonic devices.