A novel coronavirus (SARS-CoV-2) has become one of the greatest challenges of the modern world and has caused a pandemic with millions of infected people and hundreds of thousands of deaths around the globe. Transmissions occur through respiratory droplets, as well as through contaminated hands and environmental surfaces. Therefore, cleaning and disinfection of potentially contaminated surfaces becomes one of the most important measures in prevention of coronavirus transmission, along with social distancing and hand hygiene. Current CDC guidelines for preventing transmission of coronavirus specifically recommend cleaning and disinfection of frequently touched surfaces. The use of commercially available disinfectants significantly reduces microbial counts on environmental surfaces for only up to 4 hours after treatment. An alcohol-based disinfectant with a compound capable of forming a durable but removable biocidal film could combine the advantages of both approaches described above. It would combine high short-term efficacy due to the presence of alcohol and prevent microbial re-contamination due to the long-lasting efficacy of the film, while requiring less frequent applications. VRM Labs has recently developed such disinfectant, which contains 3 wt. % chitosan and 60 % wt. ethanol. Chitosan is obtained from crustacean shells and its antimicrobial and antiviral efficacy is well-established. However, it has not been used in surface disinfectants because of high viscosity of its aqueous solutions and long drying times required to form a continuous film. Our proposed formulation has low viscosity, outstanding film-forming properties and drying time similar to that for currently used disinfectants. In preliminary studies, door handles treated by this novel formulation prevented microbial growth for up to 48 hours after treatment. The goal of this Phase I study is to create an optimized prototype of chitosan-based disinfectant and to test its bactericidal and viricidal performance in a limited-scale study in a healthcare setting.
In Aim I, we will characterize film formation properties, including film thickness, film durability, abrasion resistance, and film drying times for formulations with different chitosan and ethanol concentrations. We will also evaluate in vitro antimicrobial and antiviral efficacy of these chitosan-based coatings with the most common pathogens involved known to be a source of infection on environmental surfaces, and with a surrogate coronavirus to mimic antiviral action against COVID-19.
In Aim II, we will use the optimized formulation developed in Aim I to coat several designated elevator buttons, door handles, and bed rails in a medical facility (Greenville Memorial Hospital in South Carolina). We will then collect environmental swabs from these coated surfaces on a regular basis and compare the microbial and viral counts to those obtained from similar surfaces treated according to the current hospital protocol. These experiments will help to determine the efficacy time window for the coating.
Currently used surface disinfectants tend to provide high-level activity over a relatively short period of time, typically less than 4 hours. A long-acting topical treatment of environmental surfaces would save invaluable resources such as cleansing agents and worker time and effectively reduce disease transmission. We developed a novel film-forming disinfectant that contains ~3 wt. % of chitosan and ~60 wt. % of ethanol. Upon application to a surface, it forms a durable chitosan film, which in preliminary experiments was resistant to rubbing by hand and showed biocidal properties for at least 48 hours. Chitosan is a well-established antimicrobial, antiviral, and antifungal agent, but has not been used in surface disinfectants because of high viscosity of its aqueous formulations and long drying times. We were able to overcome these problems by making a formulation with 60% ethanol. Our formulation is very thin and sprayable, and it shows excellent film-forming properties and fast drying times similar to those of currently used products. Therefore, it is expected to provide a longer and higher quality protection of environmental surfaces while requiring less frequent applications.
