Non‐thermal atmospheric plasma treatment of onychomycosis in an in vitro human nail model

Abstract

Summary Background Onychomycosis affects almost 6% of the world population. Topical azoles and systemic antifungal agents are of low efficacy and can have undesirable side effects. An effective, non‐invasive therapy for onychomycosis is an unmet clinical need. Objective Determine the efficacy threshold of non‐thermal atmospheric plasma (NTAP) to treat onychomycosis in an in vitro model. Methods A novel toe/nail‐plate model using cadaver nails and agarose media inoculated with Candida albicans was exposed to a range of NTAP doses. Results Direct exposure of C albicans and Trichophyton mentagrophytes to 12 minutes of NTAP results in complete killing at doses of 39 and 15 kPulses, respectively. Onset of reduced viability of C albicans to NTAP treatment through the nail plate occurs at 64 kPulses with 10× and 100× reduction at 212 and 550 kPulses, respectively. Conclusions NTAP is an effective, non‐invasive therapeutic approach to onychomycosis that should be evaluated in a clinical setting.

Cold sub‐atmospheric and atmospheric pressure plasma for the treatment of Trichophyton rubrum onychomycosis: An in‐vitro study

“…Not surprisingly, similarly to topical antifungal treatment,22 superficial white onychomycosis was more amenable to treatment than subungual onychomycosis. Whereas previous studies have shown the efficacy of cold atmospheric plasma for onychomycosis,[7][8][9] this study has demonstrated that cold subatmospheric pressure plasma produces a superior nail fungi growth reduction. To the best of our knowledge, this is the first study to test the applicability of low pressure plasma for onychomycosis as well as for T. rubrum.…”

“…5,6 Limited data, mainly based on in-vitro infected nail models, suggests that the use of cold atmospheric plasma (CAPP) devices for onychomycosis is beneficial for nails infected with T. rubrum, T. mentagrophytes as well as Candida albicans. [7][8][9] A comprehensive study held by Borges et al has shown that CAPP inhibits T. rubrum nail growth, adherence and infection capacity. 7 A pilot study of 13 patients has reported that CAPP is safe and well tolerated.…”

Application of Non-Thermal Plasma to Fungal Resources

“…Arthroderma benhamiae and Epidermophyton floccosum are occasionally used in experiments (Table 1). Many studies have demonstrated that Trichophyton sp., the fungal species that causes onychomycosis, was eradicated in liquid suspension or on agar media after treatment with certain NTP sources [138,139,141,146,148]. The maximum reduction of Trychophyton rubrum in nails was 6 log when treated with a floating electrode DBD plasma [140].…”

On the mechanisms of surface microdischarge plasma treatment of onychomycosis: Penetration, uptake, and chemical reactions

“…[ 19 ] A 2–6 log reduction of both Escherichia coli and Tricophyton rubrum located on the ventral side of a sealed nail plate was achieved within 20–45 min of CAP treatment. Bulson et al [ 20 ] also investigated the antifungal effect of applying pulsed dielectric barrier discharge to treat onychomycosis for a human nail model. The authors reported that Candida albicans and Trichophyton mentagrophytes were effectively inactivated by short‐term plasma treatment.…”