Microbiological Evaluation of the Disinfecting Potential of UV-C and UV-C Plus Ozone Generating Robots

Abstract

This study examined the microbicidal activity of ultraviolet (UV)-C185–256-nm irradiance (robot 1) and ozone generated at UV-C185-nm by low-pressure mercury vapor lamps (robot 2) adapted to mobile robotic devices for surface decontamination, which was achieved in less than 1 h. Depending on their wall structure and outer envelopes, many microorganisms display different levels of resistance to decontaminating agents. Thus, the need for novel disinfection approaches is further exacerbated by the increased prevalence of multidrug-resistant bacteria, as well as the potential of novel microorganisms, with the ability to cause disease outbreaks. To set up a rapid and effective approach for microorganisms propagation prevention, we focused on the effects of UV-C and ozone on a distinct microorganism survival ratio. A set of microorganisms, including Escherichia coli, Micrococcus luteus, Saccharomyces cerevisiae, Trichoderma harzianum, and Bacillus subtilis, were used to evaluate the disinfection power of UV-C and UV-C plus ozone generating robots. UV-C disinfection can be suited to ad hoc tasks, is easy to operate, requires low maintenance, does not have the need for the storage of dangerous chemicals, and does not produce by-products that may affect human health and the environment. The robotic cumulative irradiation technology developed (fluence accumulated values of 2.28 and 3.62 mJ cm−2, for robot 1 and 2, respectively), together with the production of ozone (with a maximum peak of 0.43 ppm) capable of reaching UV-C shaded surfaces, and analyzed in the current study, despite being designed for the need to reduce the risk of epidemic outbreaks in real-life scenarios, represents a versatile tool that could be employed for air and surface disinfection within many circumstances that are faced daily.

UV and violet light can Neutralize SARS-CoV-2 Infectivity

“…The germicidal effect exerted by UV light on bacteria and viruses has been widely documented since the end of 1800 [8] . UV-C light produced from low pressure mercury tubes is commonly employed in the disinfection of wastewaters, drinking water and closed environments as well as of blood products, and represents a well-established, economical and safe technology [9] , [10] , [11] , [12] , [13] , [14] . SARS-CoV-2 was shown to be highly sensitive to UV-C light [15] , [16] , [17] , [18] , although discrepancies in the results indicated that all the variables involved in the experimental setting have to be taken into account to obtain reliable and replicable data [15] .…”

Ozonized Water in Microbial Control: Analysis of the Stability, In Vitro Biocidal Potential, and Cytotoxicity

“…The antimicrobial action of O 3 herein showed is related to its powerful oxidizing action. O 3 has been widely used as an antimicrobial, in both its gaseous and aqueous form, due to its wide range of microbiological, cleaning, and metabolic activities [6,13,15,16,24,34,45,52,53]. The antimicrobial action of O 3 is related to its powerful oxidizing action.…”

“…As more antimicrobials are becoming ineffective to drug-resistant microorganisms, the focus should be shifted to alternative therapies. Research into new and non-antibiotic approaches to overcome infectious disease should be the focus of high priority research and development projects [6][7][8][9][10]. In addition, a search for methodologies aimed at reducing the spread and transmission rate for these pathogens, through contact either between humans or between humans and environments/surfaces, is warranted [11].…”

Ozone Eliminates SARS-CoV-2 from Difficult-to-Clean Office Supplies and Clinical Equipment

“…In recent years, there has been practically no innovation in the development of ozone generators in industry, due to the low demand for these devices. However, due to the COVID-19 pandemic, the variety, applicability, and versatility of ozone generators are growing quickly [ 14 , 15 , 25 , 26 , 27 ].…”