Cold plasma-driven biomolecule modifications - key or lock to effectiveness? *

In order to optimize the reactive species output of plasma sources for biomedical purposes, their ability to modify biomolecules was investigated in a series of in vitro-, in vivo, and ex-vivo experiments. The incorporation of gas-phase and liquid phase-derived atoms was observed [1], yielding new chemical groups. Peptides and proteins were found to serve as major targets [2] besides lipids that mainly underwent cleavage reactions [3]. Most reactions took place at the gas-liquid or gas-soft matter interface, indicating that transport processes at the interface are a limiting factor and penetration of chemically active short-lived species remain low. The molecular or structural functionality of the respective models was compromised by the impact of the plasma, e.g. the enzymatic activity of phospholipase A2 was reduced or lipid bilayers turned leaky. By the use of scavengers and mechanistic considerations, atomic oxygen and singlet oxygen were found most relevant. Reactive nitrogen species contributed to a minor extent.

The results devote to understanding the complex interplay between cold plasmas and biological systems and foster the new facet of tertiary plasma effects mediated and amplified by cellular signaling events in response towards the modified biomolecule.