ELECTROCHEMICAL APPROACHES: MODELING AND SCALING FOR BIOMEDICAL CHALLENGES

Dilara Ozdemir

doi:10.7273/000007076

The objective of this dissertation was to develop methods to provide better understanding of electrochemical biocide such as hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) generation and removing biofilms. My Ph.D. focused on development of mathematical models for electrochemical H2O2 and HOCl generation by electrochemical devices and scale up electrochemical HOCl generation for clinical use. H2O2 and HOCl are naturally produced as a component of the body's inflammatory wound response. Generating H2O2 and HOCl electrochemically to prevent and treat biofilm related infections is promising due to their continuous generation and their environmentally friendly nature. The first objective was to investigate the electrochemical devices that were developed previously to characterize the important parameters that would have impact on generation of H2O2 and HOCl. Two mathematical models called Electrochemical Hydrogen Peroxide Production (EHPP) and Electrochemical Hypochlorous Acid Production (EHAP) were developed to simulate H2O2 generating electrochemical bandages (e-bandages) and HOCl generating electrochemical catheters (e-catheters). EHPP model results indicate that the: diffusion limitations due to drying electrolyte, increased electrode spacing due to increased electrolyte volume and increasing temperature due to body temperature, decreases the H2O2 generation and increasing the potential applied to e-bandages increases H2O2 generation. Similarly, EHAP model results show that: when the working electrode is short, HOCl does not equally distribute, and its concentration remains ~0 mM in the parts that connect to the bloodstream after waiting for three days. Although extending polarization times and increasing the potential applied increases the local HOCl generation, its distribution is limited by the diffusion. Increasing the working electrode length and adjusting the available surface area helps to distribute HOCl equally in the e-catheter. Knowing the parameters that affect biocide generation by e-bandages and e-catheters could aid in maintenance and optimizing operating conditions of these devices. The second objective was to scale up HOCl generating e-bandages to target real biofilm/wound sizes. By keeping the biofilm to e-bandage surface area constant both biofilms and e-bandages were scaled up. The results revealed that: increasing the e-bandage size resulted in lower efficacy (viable cell reduction) for L e-bandages but M e-bandages exhibited similar efficacy to S e-bandages for 6 h treatment. Increasing the L e-bandage treatment time to 9 h for Acinetobacter baumannii ATCC BAA-1605 and 12 h for Staphylococcus aureus IDRL-6169 resulted in equivalent efficacy of S and M e-bandages for 6 h. Increasing potential applied to L e-bandages by +0.05 VAg/AgCl for A. baumannii and +0.1 VAg/AgCl for S. aureus, achieved similar results in 6 h. Tuning the operating conditions of e-bandages is promising to target unique biofilm infections.

ELECTROCHEMICAL APPROACHES: MODELING AND SCALING FOR BIOMEDICAL CHALLENGES

Files and links (1)

Abstract

Metrics

Details