  Hydrogen peroxide (H2O2) is an important signaling molecule in cancer cells.
However, the significant secretion of H2O2 by cancer cells have been rarely
observed. Cold atmospheric plasma (CAP) is a near room temperature ionized gas
composed of neutral particles, charged particles, reactive species, and
electrons. Here, we first demonstrated that breast cancer cells and pancreatic
adenocarcinoma cells generated micromolar level H2O2 during just 1 min of
direct CAP treatment on these cells. The cell-based H2O2 generation is affected
by the medium volume, the cell confluence, as well as the discharge voltage.
The application of cold atmospheric plasma (CAP) in the cancer treatment has
been intensively investigated over the past decade. Several cellular responses
to the CAP treatment have been observed including the consumption of the
CAP-originated reactive species, the rise of intracellular reactive oxygen
species, the damage on DNA and mitochondria, as well as the activation of
apoptotic events. This is a new previously unknown cellular response to CAP,
which provides a new prospective to understand the interaction between CAP and
cells.
