Application of nebulized plasma activated water as an effective antimicrobial agent in the inactivation of biofilms of clinically relevant microbial species

• Grant number: 23/10438-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2023
• End date: August 31, 2024
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Rodrigo Savio Pessoa
• Grantee: Marina Clara Ribeiro dos Santos
• Host Institution: Divisão de Ciências Fundamentais (IEF). Instituto Tecnológico de Aeronáutica (ITA). Ministério da Defesa (Brasil). São José dos Campos , SP, Brazil
• Associated research grant: 19/05856-7 - Use of low temperature atmospheric pressure plasma in dentistry: from laboratory bench to clinics, AP.TEM

Abstract

In recent years, Plasma Activated Water (PAW) has gained attention due to its inactivating effects on microbial species such as bacteria and fungi. Plasma as a liquid activating agent has been applied directly or indirectly. Direct-PAW (DPAW) is used to inactivate microorganisms during plasma water treatment. On the other hand, indirect PAW (IPAW) is used after activation and can be used immediately after preparation or it can be stored and used after a few days. IPAW is useful in plasma medicine as biologically active formulations that may show long-term efficacy against multidrug-resistant strains, viruses and fungi, acting as antiseptics or disinfectants. Despite the tremendous biotechnological appeal of PAW due to potent antimicrobial effects and wide application in clinical practice, some challenges need to be overcome. A recent example was triggered in 2019 by the coronavirus disease (COVID-19) pandemic. New challenges have emerged in the treatment of infections caused by long-term intubations induced by bacterial colonization in tubes attached to the airways. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a high number of intubated and tracheostomized patients worldwide. One of the complications of prolonged intubation for ventilatory assistance is tracheal stenosis, which is the segmental reduction in the diameter of the airways. The contact between the surface of the prosthesis and the external environment allows the formation of an active biofilm on the surface of the silicone that can interact with the surrounding diseased trachea and interfere with the resolution of the stenosis particularly in the presence of concomitant factors such as gastroesophageal reflux. The plasma-activated liquid has a broad inactivation effect on bacterial and fungal species and is a potential candidate for controlling the respiratory tract microbiota. There is the clinical impossibility of using liquid water in the respiratory tract, which leads to extraction and death by asphyxiation. On the other hand, nebulized PAW delivered via tube and inhaled is a viable possibility and requires investigation for its applications in airway prostheses such as the silicone T-tube. The usual method of administering drugs into the airways. In this scientific initiation project, a plasma jet generated in a "gliding arc" type reactor operated at atmospheric pressure using different types of gases, such as atmospheric air, argon and/or oxygen, will be placed millimeters from the surface of the water in IPAW mode. After treatment, nebulized PAW (NPAW) will be generated along linear and T-type silicone tubes, and its physicochemical characteristics will be measured. Regarding the microbiological assays, biofilm strains of Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 27853) and Candida albicans (SC 5314) will be exposed by NPAW during different times and their antimicrobial activity will be measured.