  Plasma medicine is an emerging and innovative interdisciplinary research
field combining biology, chemistry, physics, engineering, and medicine.
However, the safe clinical application of cold atmospheric plasma (CAP)
technology is still a challenge. Here, we examine the use of aluminum (Al) foam
with three pores-per-inch (PPI) ratings in clinical plasma applications. Al
foams can filter sparks to avoid damage from high voltage discharge during
surgery and efficiently deliver reactive species generated in CAP to the
target. The sparks appear and plasma intensity increases at the foam/discharge
interface, which just slightly increases the interface temperature without
changing the interface microstructure during a 30-minute treatment. After CAP
penetrated the Al foams, N2, N2+, *OH, O, and He emission peaks were
characterized, and the highest values appeared using Al foams with 10 PPI. CAP
with and without Al foam intermediating was used to treat deionized water, and
the results indicate CAP in combination with 10 PPI Al foam led to much higher
ROS concentration than CAP alone. For melanoma cell experiments, CAP with and
without Al foam had a similar effect on cell viability after 30-second
treatment, while CAP with the 10-PPI Al foam had much higher killing efficiency
than CAP alone after 60-second treatment. In summary, 10-PPI Al foam can not
only prevent damage to tissues resulting from high discharge voltage during
clinical surgery but also increase the delivery efficiency of reactive species
generated in plasma for biomedical applications.
