Development and application of atmospheric pressure cold plasma jet with antimicrobial efficacy against infectious biofilms in diabetic foot ulcers

Abstract

Diabetic Foot Ulcer (DFU) is one of the biggest costs to health systems. Infections in DFU are characterized when the microbial load exceeds the value of 10^5 organisms / gram in the biofilms, where Staphylococcus, Streptococcus, Proteobacteria, Pseudomonas aeruginosa and coliforms are typically found. In addition, bacteria within biofilms are protected from various stresses, including immune responses and antimicrobial agents which compromises the effectiveness of the main current antiseptics, such as chlorhexidine gluconate. The mean treatment time using conventional methods aiming cure of DFU without surgical intervention is 12 weeks. The typical survival rate of up to 5 years after recurrence of DFU ranges from 50-60%, which makes it worse than many cancers. Another study has shown that survival rates in the elderly for 1, 2 and 5 years are 81, 69 and 29%, respectively. The occurrence of DFU is a strong predictor of death within 10 years. In this context, the objective of this work is the development and application of atmospheric pressure cold plasma torch with antimicrobial efficacy against infectious biofilms in diabetic foot ulcers as a new approach for the treatment of DFUs. In this first phase, the antimicrobial efficacy of the cold plasma torch will be demonstrated by means of the evaluation of the colony reduction factor (CRF) when applied separately to biofilms formed by Staphylococcus aureus (representative of Gram-positive bacteria) and Pseudomonas aeruginosa (representative of Gram-negative bacteria). As a result, it is expected that the embodiment of this project will result in an antimicrobially effective cold plasma torch operating at atmospheric pressure and having a temperature of less than or equal to 55°C, i.e. parameters which characterize it as a tissue tolerable plasma or TTP. The most recent consolidation of data from Brazil concerning DM and DFU is from 2014 and indicated a population of 9.2 million people affected with DM, of this population were identified 829.7 thousand patients with complications associated with feet. Considering the base year 2014, the SUS funded Int $ 361 million with general treatments (doctor visits, emergency room, nursing, hospitalization, amputation, etc.) related to the DFU. In this context, the achievement of the aforementioned objective represents a first embodiment in order to present a dedicated solution for the treatment of the DFU in order to provide a more effective therapy to the patient, which represents benefits for the administrations of the public and private health networks. (AU)