Date of Award

Winter 2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biomedical Engineering

First Advisor

Scott Poh

Abstract

Oxidative stress, an excess of endogenous or exogenous reactive oxygen species (ROS) in the body, is closely aligned with inflammatory responses. ROS such as hydrogen peroxide, superoxide, and radical hydroxyl ion serve essential functions in fighting infection, but chronic elevation of these species irreversibly damages cellular components. Given the central role of inflammation in a variety of diseases, including Alzheimer’s Disease, atherosclerosis, and rheumatoid arthritis, a low-cost, extracellular, non-invasive assay of ROS is needed.

This work reports the use of a platinum microelectrode array (Pt MEA)-based ceramic probe to detect time- and concentration-dependent variations in hydrogen peroxide (H2O2) production by activated macrophages. RAW 264.7 cells were placed under oxidative stress by activation with lipopolysaccharides (LPS). Chronoamperometry was then employed to detect the quantity of H2O2 released by cells at various time intervals up to 48 hours. The most stimulatory concentration of LPS was first identified. Further experiments assessed the anti-inflammatory effect of dexamethasone (Dex), a commonly prescribed steroid medication. As expected, the probe detected significantly increased H2O2 production by LPS-doped macrophages. This pro-inflammatory effect was diminished, but not resolved, in LPS-doped cells treated with Dex.

The long-term goal of this research is the development of a non-invasive, robust, multiplexed, point-of-care test of ROS and inflammation. Given the robustness of the materials and the ease of modifying additional microelectrodes within the same probe, these results indicate that the probe is a suitable candidate for further study.

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