# Antifungal Efficacy of Plasma-Activated Liquids against Candida albicans: A Potential Alternative for Oral Candidiasis Treatment

## TL;DR

This study explores plasma-activated liquids as a potential new treatment for oral candidiasis, showing they can reduce Candida albicans growth without harming human cells.

## Contribution

Demonstrates the antifungal and antibiofilm efficacy of argon-derived plasma-activated liquids against Candida albicans with low cytotoxicity.

## Key findings

- Argon-activated saline and distilled water reduced planktonic Candida albicans viability by ~50% after 30 minutes.
- Plasma-activated liquids retained antifungal activity against 24- and 48-hour biofilms and after 24 hours of freezing.
- Argon-derived plasma-activated liquids showed no significant toxicity to mammalian cells in cytotoxicity assays.

## Abstract

The increasing incidence of oral candidiasis refractory
to conventional
antifungal treatments, coupled with limited therapeutic alternatives,
underscores an urgent need for novel interventions. Plasma-activated
liquids (PALs), generated via nonthermal plasma, have shown antimicrobial
promise, yet their antifungal efficacy, particularly against Candida albicans, remains understudied, and no investigations
have addressed their use in oral candidiasis. In this study, PALs
were produced using a gliding-arc plasma reactor with argon and compressed
air (pure and mixed) at gas flows of 1.5 and 3.0 L/min, and an average
power range of 25–60 W. Two liquid substrates, distilled water
and 0.9% sodium chloride (saline) solution, were plasma-activated
and characterized in terms of physicochemical parameters (pH, ORP,
TDS, conductivity) and reactive oxygen and nitrogen species (RONS),
including H2O2, NO2
–, NO3
–, HNO2, and O3, via spectrophotometry and reactive-strip analysis. The antifungal
activity of PALs was assessed against C. albicans in both planktonic and biofilm forms. After 30 min exposure, argon-activated
saline (S1) and distilled water (D1), and argon–air activated
distilled water (D2), achieved ∼50% reduction in planktonic
viability; only S1 and D1 maintained significant effects on 24- and
48 h biofilms. Moreover, PALs frozen at −18 °C for 24
h retained antifungal efficacy. Cytotoxicity assays using Vero cells
confirmed that D1 and S1 were nontoxic over both immediate and 24
h exposures (viability >70%). In sum, argon-derived PALs based
on
distilled water and saline exhibited selective antifungal and antibiofilm
activity against C. albicans, without
toxicity to mammal cells, highlighting their potential as adjunctive
therapies in candidiasis management. These findings support further
optimization for clinical applications.