Plasma-activated vapor for sanitization of hands

Abstract

Compliance with established hand hygiene protocols is extremely low in clinical units because these protocols mandate long hand-washing times. This phenomenon results in more numerous healthcare-associated infections and severely compromises the health of patients. Poor compliance is motivated by the hand-washing times required by soaps and sanitizers, which can be as long as 2 minutes. Cold atmospheric plasma is an alternative antimicrobial technology that can reduce the time required for sanitization to approximately 5 s. However, despite many advantages, existing plasma devices generate ozone as a toxic byproduct in high concentrations, so there is a need for a plasma-based hand sterilization system that: (1) produces enough reactive oxygen and nitrogen chemical species to achieve a microbial kill rate that is able to compete with existing hand-sanitizing technology and (2) counteracts the conversion of plasma into ozone. The design presented here used water vapor to perform these functions and to stabilize reactive plasma species. The plasma system delivers a plasma-activated water vapor mixture to a hand surface by the action of a humidifier that is much safer and more efficient than other plasma sanitization systems on the market. The operational prototype consists of three stages: ultrasonic water vapor generation, dielectric-barrier discharge plasma generation, and a dispensary tubing system. We have shown that the device is capable of disaggregating bacteria in 5 s with significant reductions in ozone concentrations through the use of water vapor.