Evaluation of the Cytotoxicity of Various Hand Disinfectants and Ozonated Water to Human Keratinocytes in a Cultured Epidermal Model

Abstract

OBJECTIVE To evaluate the cytotoxicity of various hand disinfectants and ozonated water to human keratinocytes using a cultured epidermal model. DESIGN Using a test protocol from the Organization for Economic Co-operation and Development, investigators applied hand disinfectants containing either 83% ethanol, 0.2% benzalkonium chloride, 0.5% povidone-iodine, 1% chlorhexidine, 1% chlorhexidine ethanol, or ozonated water to a cultured human epidermal model. Surface morphology and histologic changes were evaluated by scanning electron microscopy and hematoxylin-eosin staining. MAIN OUTCOME MEASURES Production of inflammatory cytokine interleukin 1α by keratinocytes and cell death rate. MAIN RESULTS Electron microscopic analysis revealed the creation of small holes on the stratum corneum, and hematoxylin-eosin staining revealed perinuclear vacuolation of keratinocytes and cells with a condensed nucleus. Interleukin 1α was detected in the culture supernatants. More than 80% of keratinocytes did not survive after a 15-minute application of disinfectants. However, no significant damage was detected with ozonated water. CONCLUSIONS Ozonated water did far less damage to keratinocytes than the tested disinfectants. Although the ability of ozonated water to disinfect hands of medical staff members requires further study, it might serve as an alternative with minimum cytotoxicity.

Inactivation of SARS-CoV-2 by Ozonated Glycerol

“…However, these disinfectants have been shown to cause skin irritation, and as handwashing measures have now been strengthened, healthcare professionals were reported to exhibit increased skin irritation (Erdem et al, 2020 ; Guertler et al, 2020 ; Lan et al, 2020 ). Recent studies have shown that OW is less irritating to the skin than traditional disinfectants, raising interest in OW as an alternative handwashing treatment (Breidablik et al, 2019 ; Kashiwazaki et al, 2020 ). Likewise, OG is also less irritating to the skin and has a longer ozone half-life than OW (Fukui et al, 2015 ; Wang et al, 2011 ).…”

Inactivation Activities of Ozonated Water, Slightly Acidic Electrolyzed Water and Ethanol against SARS-CoV-2

“…Even though EtOH is more stable than OW and SAEW, its skin irritation and the existence of alcohol-intolerant people are disadvantages. Previous reports suggest that the skin irritancy of OW is lower than that of EtOH [ 15 , 16 ]. In contrast, since SAEW is also considered to be safe and has low irritation to skin and mucous membranes, it has been proposed for use as a disinfectant for normal and wounded skin [ 17 ].…”

Critical Review and Research Needs of Ozone Applications Related to Virus Inactivation: Potential Implications for SARS-CoV-2

“…Routine disinfection practices have evolved during the ongoing pandemic, and several sectors have required enhanced disinfection of contact surfaces. SARS-CoV-2 has shown to persist on surfaces up to 72 hours (van Doremalen et al 2020), whereas other coronaviruses have persisted up to 9 days on surfaces (Kampf et al 2020). While surface contact is not considered to be the primary SARS-CoV-2 transmission route, it should not be entirely ignored.…”

“…Despite issues associated with respiratory exposure to ozone, aqueous ozone does not damage human skin cells, as its cellular degradation action is selective to microbial cells (Gupta and Mansi 2012). When experimentally compared with various hand disinfectants, ozonated water resulted in minimal cytotoxicity to the human keratinocytes (Kashiwazaki et al 2020). Aqueous ozone has been considered as an alternative to chlorine-based disinfectants in food processing (Rice, Graham, and Lowe 2002), and has great potential of improving disinfection toward COVID-19 control in various sectors.…”

“…Traditional sanitizers have shown to cause skin irritation, causing healthcare workers to experience an increased amount of skin irritation in response to heightened handwashing measures (Erdem et al 2020;Guertler et al 2020;Lan et al 2020). Previous studies have shown ozonated water to irritate skin less than traditional sanitizers (Breidablik et al 2019;Kashiwazaki et al 2020), increasing the interest in ozonated water as an alternative handwashing treatment. However, current knowledge is based entirely on the reduction of laboratory-propagated bacterial species inoculated onto hands (Appelgrein et al 2016;Breidablik et al 2019;Nakamura et al 2018); there are currently no studies evaluating inactivation of viruses.…”