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Cleaning, decontamination or sterilisation of medical instruments and accessories is one of the most crucial demands in health care facilities in order to guarantee safety of their repetitive utilisation. From this point of view, new challenges concern the removal of proteinous residuals reported to be capable to invoke severe neurodegenerative diseases (e.g. Creutzfeld-Jakob disease or its variant), since it has been currently shown that certain proteins exhibit an extraordinarily high resistance both to physical and chemical treatment. It is believed that the application of non-equilibrium discharges recently used for sterilisation of bacterial spores or de-activation of pyrogenic compounds could be employed also for the destruction of protein films, maintaining all the advantages of this technique – low temperature process, safety and efficiency. Although the possibility to remove or inactivate different proteins has been already demonstrated, a systematic study of the nature and mechanism of plasma-protein interaction is still missing, which is in particular true with respect to the rate of protein modifications under different process conditions. In order to fill this experimental gap low-pressure microwave discharge sustained in different gases and gas mixtures has been used in this study to treat the model protein Bovine serum albumine (BSA). The effect of plasma on treated samples has been afterwards evaluated by means of different surface diagnostic methods (profilometry, imaging ellipsometry, AFM), aimed predominantly at the estimation of the BSA removal rate as well as at the morphological changes induced by the discharge with the objective to identify the most favourable discharge mixture. According to the obtained results it can be concluded that both the etching rate and the degree of BSA erosion on the nanometric scale is strongly dependent on the used discharge mixture, namely on the presence of atomic oxygen or hydrogen. |