Sterilization and drug susceptibility study of Candida Albicans biofilm on denture base resin treated by direct and alternating current atmospheric pressure cold plasma microjet

Direct current and alternating current cold PMJs were employed to treat the Candida Albicans biofilm formed on denture base resin for 1, 2, 4, 6, 8 minutes with different working gases. Scanning electron microscope (SEM) was employed to observe the morphology change and results showed that evident cell rupture was observed in experimental groups compared with control groups. By using CFU counting method, it was observed that the biofilm can be killed completely in 8 min in four plasma groups. Intro-cellular protein (ICP) was measured with BCA protein assay reagent and the results indicated that the protein concentration of treated groups dropped remarkably over the prolonged treatment, which suggested that the mechanism underlying the sterilization phenomenon was strongly associated with protein loss. Besides, drug susceptibility was evaluated by using amphotericin B and fluconazole as antifungal drug. Results suggested that strains treated with plasma showed a higher sensitivity to antifungal drugs when compared with control groups; In conclusion, AC and DC driven plasma alone or assisted with drug therapy can provide a valuable tool for Candida Albicans infection, and it will be helpful for protecting denture based resin from denture stomatitis.