Kinetic Analysis of Delivery of Plasma Reactive Species Into Cells Immersed in Culture Media

Recently, the plasma medicine received a lot of attention in the plasma and biology community. Most of the plasma treatment targets are living tissues and cells immersed in liquids (such as blood or culture media). Reactive species generated by plasma in the gas phase are transported into the liquid and possibly converted to different types of reactive species, so that they can affect tissues or cells. In this paper, we presented a numerical investigation of the interaction between the plasma and the cells immersed in the culture media. The space and time evolution of dissolved reactive species [reactive oxygen species (O
₂
^-
, OH, H
₂
O
₂
, HO
₂
, and O
₃
) and reactive nitrogen species (O
₂
NO
^-
, NO, NO
₂
^-
, NO
₃
^-
, and O
₂
NOH)] are studied by the mass balance model in liquid. The reaction mechanism and the effective transportation range of dissolved reactive species are analyzed. The pH of the liquid has significant effects on the concentration of O
₂
^-
, HO
₂
, O
₂
NO
^-
, and O
₂
NOH in the culture media. The increasing concentration and the higher permittivity through the cell membrane of HO
₂
and O
₂
NOH at acidic pH are consistent with higher bacterial inactivation efficiency of plasma treatment in acidic pH environment. The cellular and the subcellular concentration of HO
₂
, O
₂
NO
^-
, and O
₂
NOH are studied by the conservation equations in a spherically symmetric concentration field. The plasma treatment increased the cellular concentration of O
₂
NO
^-
over ten times. The HO
₂
generated by plasma aqueous species was the only way for superoxide to penetrate cell membrane and damage cytosolic fumarase B. The cellular plasma reactive species are also sensitive to the pH of culture media.