On our way to understand sterilization mechanisms — Inactivation and modification of bio-macromolecules by H2 and O2 plasma

A low-pressure VHF-CCP is used to investigate the impact of H₂ and O₂ plasma on bio-macromolecules. Since both, plasma and cells, are very complex systems, bio-macromolecules are used to identify possible inactivation mechanisms. With the ubiquitous enzyme GAPDH, enzyme activity tests were carried out before and after plasma treatment, revealing that oxygen plasma leads to a higher inactivation than hydrogen plasma. SDS PAGE indicates that neither fragmentation nor unfolding occurs. With mass spectrometry we could identify mainly oxidation of cysteine in case of oxygen plasma as possible inactivation mechanism, whereas in case of hydrogen plasma deamidation takes place. The inactivation results are correlated with plasma parameters, obtained with optical emission spectroscopy.