Modulating Plasma-Induced Thiol Chemistry In Liquids

Cold physical plasmas are currently under investigation in various fields of industry and medicine. Clinical trials using plasma for wound healing are well under way. In addition, investigations of plasmas for cancer treatment offer promising findings, too. However, the chemical interactions between plasmas and their biological targets are only partly understood. The complex chemical cocktails generated by plasma can affect various biological structures [1]. A better understanding of these reactions would allow tuning and modulating plasmas for specific tasks, e.g. triggering wound healing or apoptosis cascades. One prevalent impact of plasma on biological targets is the chemical modification of thiol groups, which carry out various critical functions in the human body, such as cell signaling and protein structure formation. As thiols are involved in many regulatory and functional processes in tissues, an in-depth understanding of the impact of plasma treatment on thiols is highly relevant to optimize plasmas for medical applications.

To shed light onto these interactions, various thiol-containing model substrates were investigated with different plasma sources [2,3]. Using a normalized target substrate, the impact of the different plasma sources can be compared not by means of a physical characterization but by their chemical impact [4]. Stepwise increase of sample complexity allows monitoring how thiols are affected by plasma treatment in an ever more complex environment. The combination of experimental evidence and MD simulations permit a comprehensive overview of chemical processes induced by plasma treatment. This combined approach allows for a more throughout investigation of modifications on a molecular level and helps to understand fundamental plasma chemistry processes. Knowledge how different targets, ranging from small molecules to various proteins are affected by plasma treatment helps to understand how subsequent cellular responses can be triggered and what cross-reactions might be expected by plasma treatment.