In this MEDICA-tradefair.com interview, Dr. Kristina Lachmann explains how atmospheric pressure plasmas are generated and used for disinfection purposes and reveals how a robot can use the technology to facilitate cleaning and disinfection – not only in hospitals but in all high traffic areas.
Dr. Lachmann, what is atmospheric pressure plasma?
Dr. Kristina Lachmann: Plasma is called the fourth state of matter, right along with solid, liquid and gas. Plasmas naturally occur in nature. We encounter hot plasmas in lightning flashes and cold plasmas in the northern lights at the Arctic Circle. Atmospheric pressure plasmas are cold plasmas. They are created by applying very high voltage to a gas under atmospheric pressure. This prompts the gas atoms to split into ions, electrons, and radicals, producing reactive species that interact with surfaces and act as a disinfectant against microorganisms.
How does plasma affect pathogens?
Lachmann: Radicals break the bonds of organic molecules. Simultaneously, plasma glows because the excited electrons fall back down to their lower energy states and give off energy in the process. This creates UV radiation, which damages cells or destroys their DNA depending on the type of gas.
Your Institute developed a plasma system for the cleaning and disinfection of surfaces. What is its intended use?
Lachmann: We designed it as an interchangeable tool that can be managed by a mobile disinfection robot – in conjunction with other cleaning methods. The device could disinfect intricate components such as door handles or contact areas with a simpler design including light switches or elevator buttons and surfaces. The plasma can also clean and disinfect moisture-sensitive and porous textiles using a virtually dry approach. The objective is to have the robot use the different tools and manage the process autonomously, thus turning it into an integral part of standard cleaning operations.
Having said that, the use of plasma technology for disinfection should always be the last step in the cleaning process. It is merely an added tool since all heavy-duty organic matter and soiling must first be removed before its eventual application. However, surfaces where there is no visible contamination can be disinfected this way.