Research Symposium

BIO

Raphaela De Faria Aildasani is a junior at Florida State University majoring in Interdisciplinary Medical Sciences and pursuing a career in medicine. She has been conducting research in the Lazenby Lab for the past 10 months, where she works on developing carbon nanoelectrodes and functionalizing them as pH sensors through platinum and iridium deposition.

Fabrication of pH Sensors Modified with Platinum and Iridium Oxide

Abstract

Accurate detection of small pH changes is critical for studying biological systems, particularly in the tumor microenvironment where cancer cells exhibit altered metabolic activity that leads to extracellular acidification. In this study, carbon nanoelectrodes were fabricated through sequential surface modification with platinum followed by iridium and evaluated as high-stability pH sensors. Cyclic voltammetry was performed to confirm the electrochemical activity and stability of the carbon nanoelectrodes. Platinum was then deposited onto the electrode surface, followed by iridium deposition to improve conductivity and signal stability. The modified electrodes were calibrated by measuring the open circuit potential (OCP) across a range of pH solutions, and calibration curves were constructed and compared against the theoretical response predicted by the Nernst equation. The resulting sensors demonstrated durable and reproducible behavior with near-Nernstian sensitivity, enabling detection of small pH variations. Most importantly, the sensors maintained stability over multiple days of testing. These findings suggest that platinum- and iridium-modified carbon nanoelectrodes show promise for monitoring localized pH changes associated with cancer cell metabolism.

Keywords: pH sensing, Carbon nanoelectrode, Deposition