Indirect Inactivation of Candida guilliermondii by Using a Plasma Synthetic Jet Actuator: Effect of Advected Charged Particles

Abstract

Plasma synthetic jet actuators (PSJAs) demonstrated their ability to produce a Candida guilliermondii, the passage of charges and their migration toward the sample can either be allowed or prevented log colony-forming unit (CFU) reduction were observed for agar substrate and saline solution, respectively, at the highest energy dose treatment with the grid grounded. Under the same condi-1 log CFU. In addition to biological tests, chemical analyses have been carried out to identify the C. guilliermondii, both on agar substrate and saline solution, and the inactivation properties of free charges advected by this

Atmospheric‐pressure plasma actuators: Enhancement of the free charges' transport mechanism

“…When the wire mesh is grounded (red line), about 95% of the charges inside the flow are conveyed by means of the mesh to ground, severely limiting the number of charge particles reaching the target surface. Unlike what was previously seen in Neretti et al, [ 22 ] in Actuator 2, the distribution of the surface potential increases by the 25% when the mesh is left floating, compared with the potential measured without mesh. A possible explanation for this increment is a different fluid‐dynamic regime for the two conditions.…”

“…Hence, the distance between the plasma end and the target is about 20 mm. The same distance was used to obtain the results reported in the investigation described in Neretti et al [ 22 ] where Actuator 3 (annular geometry) was tested.…”

“…In the following, the PVC linear actuator will be named as “Actuator 1.” This geometry was chosen to perform a direct comparison in charge delivery efficacy with respect to the annular PSJA described in our previous works. [ 11,22 ] This PSJA, namely “Actuator 3,” was made by using a 2‐mm‐thick PVC, and it is characterized by an octagonal geometry with a side length of 12 mm. In a previous work, [ 11 ] it has been demonstrated that this octagonal geometry produces an induced jet similar to that generated by an annular actuator.…”

“…In a previous work, our group experimentally pointed out the contribution of the charge particles of a PSJA in Candida Guillermondi indirect inactivation. [ 22 ] In all tests, the treated sample was placed at 2‐cm distance from the plasma surface. Results showed that an additional Log 1 colony‐forming unit reduction was achieved when the free charges produced by the PSJA could reach the sample.…”

“…In this way, the merging of the tangential jets occurring in the PSJA configuration is avoided, and the recombination of the charged particles produced in the plasma is reduced. By following experiments carried out in a previous work, [ 22 ] a metal wire mesh between the actuator and the target had been added. The presence of the mesh was utilized to verify the possibility to prevent charged particles to reach the sample.…”